Imported Upstream version 60upstream/60

13 files changed, 9592 insertions, 0 deletions

diff --git a/src/cmd/5g/Makefile b/src/cmd/5g/Makefile
new file mode 100644
index 000000000..b47014a4e
--- /dev/null
+++ b/src/cmd/5g/Makefile
@@ -0,0 +1,36 @@
+# Copyright 2009 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../Make.inc
+O:=$(HOST_O)
+
+TARG=5g
+
+HFILES=\
+	../gc/go.h\
+	../5l/5.out.h\
+	gg.h\
+	opt.h\
+
+OFILES=\
+	../5l/enam.$O\
+	cgen.$O\
+	cgen64.$O\
+	cplx.$O\
+	galign.$O\
+	ggen.$O\
+	gobj.$O\
+	gsubr.$O\
+	list.$O\
+	peep.$O\
+	pgen.$O\
+	reg.$O\
+
+LIB=\
+	../gc/gc.a\
+
+include ../../Make.ccmd
+
+%.$O: ../gc/%.c
+	$(HOST_CC) $(HOST_CFLAGS) -c -I. -o $@ ../gc/$*.c
diff --git a/src/cmd/5g/cgen.c b/src/cmd/5g/cgen.c
new file mode 100644
index 000000000..6e2fbe20f
--- /dev/null
+++ b/src/cmd/5g/cgen.c
@@ -0,0 +1,1328 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "gg.h"
+
+/*
+ * generate:
+ *	res = n;
+ * simplifies and calls gmove.
+ */
+void
+cgen(Node *n, Node *res)
+{
+	Node *nl, *nr, *r;
+	Node n1, n2, n3, f0, f1;
+	int a, w;
+	Prog *p1, *p2, *p3;
+	Addr addr;
+
+	if(debug['g']) {
+		dump("\ncgen-n", n);
+		dump("cgen-res", res);
+	}
+	if(n == N || n->type == T)
+		goto ret;
+
+	if(res == N || res->type == T)
+		fatal("cgen: res nil");
+
+	while(n->op == OCONVNOP)
+		n = n->left;
+
+	if(n->ullman >= UINF) {
+		if(n->op == OINDREG)
+			fatal("cgen: this is going to misscompile");
+		if(res->ullman >= UINF) {
+			tempname(&n1, n->type);
+			cgen(n, &n1);
+			cgen(&n1, res);
+			goto ret;
+		}
+	}
+
+	if(isfat(n->type)) {
+		if(n->type->width < 0)
+			fatal("forgot to compute width for %T", n->type);
+		sgen(n, res, n->type->width);
+		goto ret;
+	}
+
+
+	// update addressability for string, slice
+	// can't do in walk because n->left->addable
+	// changes if n->left is an escaping local variable.
+	switch(n->op) {
+	case OLEN:
+		if(isslice(n->left->type) || istype(n->left->type, TSTRING))
+			n->addable = n->left->addable;
+		break;
+	case OCAP:
+		if(isslice(n->left->type))
+			n->addable = n->left->addable;
+		break;
+	}
+
+	// if both are addressable, move
+	if(n->addable && res->addable) {
+		if(is64(n->type) || is64(res->type) ||
+		   n->op == OREGISTER || res->op == OREGISTER ||
+		   iscomplex[n->type->etype] || iscomplex[res->type->etype]) {
+			gmove(n, res);
+		} else {
+			regalloc(&n1, n->type, N);
+			gmove(n, &n1);
+			cgen(&n1, res);
+			regfree(&n1);
+		}
+		goto ret;
+	}
+
+	// if both are not addressable, use a temporary.
+	if(!n->addable && !res->addable) {
+		// could use regalloc here sometimes,
+		// but have to check for ullman >= UINF.
+		tempname(&n1, n->type);
+		cgen(n, &n1);
+		cgen(&n1, res);
+		return;
+	}
+
+	// if result is not addressable directly but n is,
+	// compute its address and then store via the address.
+	if(!res->addable) {
+		igen(res, &n1, N);
+		cgen(n, &n1);
+		regfree(&n1);
+		return;
+	}
+
+	if(complexop(n, res)) {
+		complexgen(n, res);
+		return;
+	}
+
+	// if n is sudoaddable generate addr and move
+	if (!is64(n->type) && !is64(res->type) && !iscomplex[n->type->etype] && !iscomplex[res->type->etype]) {
+		a = optoas(OAS, n->type);
+		if(sudoaddable(a, n, &addr, &w)) {
+			if (res->op != OREGISTER) {
+				regalloc(&n2, res->type, N);
+				p1 = gins(a, N, &n2);
+				p1->from = addr;
+				if(debug['g'])
+					print("%P [ignore previous line]\n", p1);
+				gmove(&n2, res);
+				regfree(&n2);
+			} else {
+				p1 = gins(a, N, res);
+				p1->from = addr;
+				if(debug['g'])
+					print("%P [ignore previous line]\n", p1);
+			}
+			sudoclean();
+			goto ret;
+		}
+	}
+
+	// otherwise, the result is addressable but n is not.
+	// let's do some computation.
+
+	nl = n->left;
+	nr = n->right;
+
+	if(nl != N && nl->ullman >= UINF)
+	if(nr != N && nr->ullman >= UINF) {
+		tempname(&n1, nl->type);
+		cgen(nl, &n1);
+		n2 = *n;
+		n2.left = &n1;
+		cgen(&n2, res);
+		goto ret;
+	}
+
+	// 64-bit ops are hard on 32-bit machine.
+	if(is64(n->type) || is64(res->type) || n->left != N && is64(n->left->type)) {
+		switch(n->op) {
+		// math goes to cgen64.
+		case OMINUS:
+		case OCOM:
+		case OADD:
+		case OSUB:
+		case OMUL:
+		case OLSH:
+		case ORSH:
+		case OAND:
+		case OOR:
+		case OXOR:
+			cgen64(n, res);
+			return;
+		}
+	}
+
+	if(nl != N && isfloat[n->type->etype] && isfloat[nl->type->etype])
+		goto flt;
+	switch(n->op) {
+	default:
+		dump("cgen", n);
+		fatal("cgen: unknown op %N", n);
+		break;
+
+	case OREAL:
+	case OIMAG:
+	case OCOMPLEX:
+		fatal("unexpected complex");
+		break;
+
+	// these call bgen to get a bool value
+	case OOROR:
+	case OANDAND:
+	case OEQ:
+	case ONE:
+	case OLT:
+	case OLE:
+	case OGE:
+	case OGT:
+	case ONOT:
+		p1 = gbranch(AB, T);
+		p2 = pc;
+		gmove(nodbool(1), res);
+		p3 = gbranch(AB, T);
+		patch(p1, pc);
+		bgen(n, 1, p2);
+		gmove(nodbool(0), res);
+		patch(p3, pc);
+		goto ret;
+
+	case OPLUS:
+		cgen(nl, res);
+		goto ret;
+
+	// unary
+	case OCOM:
+		a = optoas(OXOR, nl->type);
+		regalloc(&n1, nl->type, N);
+		cgen(nl, &n1);
+		nodconst(&n2, nl->type, -1);
+		gins(a, &n2, &n1);
+		gmove(&n1, res);
+		regfree(&n1);
+		goto ret;
+
+	case OMINUS:
+		nodconst(&n3, nl->type, 0);
+		regalloc(&n2, nl->type, res);
+		regalloc(&n1, nl->type, N);
+		gmove(&n3, &n2);
+		cgen(nl, &n1);
+		gins(optoas(OSUB, nl->type), &n1, &n2);
+		gmove(&n2, res);
+		regfree(&n1);
+		regfree(&n2);
+		goto ret;
+
+	// symmetric binary
+	case OAND:
+	case OOR:
+	case OXOR:
+	case OADD:
+	case OMUL:
+		a = optoas(n->op, nl->type);
+		goto sbop;
+
+	// asymmetric binary
+	case OSUB:
+		a = optoas(n->op, nl->type);
+		goto abop;
+
+	case OLSH:
+	case ORSH:
+		cgen_shift(n->op, nl, nr, res);
+		break;
+
+	case OCONV:
+		if(eqtype(n->type, nl->type) || noconv(n->type, nl->type)) {
+			cgen(nl, res);
+			break;
+		}
+		if(nl->addable && !is64(nl->type)) {
+			regalloc(&n1, nl->type, res);
+			gmove(nl, &n1);
+		} else {
+			if(n->type->width > widthptr || is64(nl->type) || isfloat[nl->type->etype])
+				tempname(&n1, nl->type);
+			else
+				regalloc(&n1, nl->type, res);
+			cgen(nl, &n1);
+		}
+		if(n->type->width > widthptr || is64(n->type) || isfloat[n->type->etype])
+			tempname(&n2, n->type);
+		else
+			regalloc(&n2, n->type, N);
+		gmove(&n1, &n2);
+		gmove(&n2, res);
+		if(n1.op == OREGISTER)
+			regfree(&n1);
+		if(n2.op == OREGISTER)
+			regfree(&n2);
+		break;
+
+	case ODOT:
+	case ODOTPTR:
+	case OINDEX:
+	case OIND:
+	case ONAME:	// PHEAP or PPARAMREF var
+		igen(n, &n1, res);
+		gmove(&n1, res);
+		regfree(&n1);
+		break;
+
+	case OLEN:
+		if(istype(nl->type, TMAP) || istype(nl->type, TCHAN)) {
+			// map has len in the first 32-bit word.
+			// a zero pointer means zero length
+			regalloc(&n1, types[tptr], res);
+			cgen(nl, &n1);
+
+			nodconst(&n2, types[tptr], 0);
+			regalloc(&n3, n2.type, N);
+			gmove(&n2, &n3);
+			gcmp(optoas(OCMP, types[tptr]), &n1, &n3);
+			regfree(&n3);
+			p1 = gbranch(optoas(OEQ, types[tptr]), T);
+
+			n2 = n1;
+			n2.op = OINDREG;
+			n2.type = types[TINT32];
+			gmove(&n2, &n1);
+
+			patch(p1, pc);
+
+			gmove(&n1, res);
+			regfree(&n1);
+			break;
+		}
+		if(istype(nl->type, TSTRING) || isslice(nl->type)) {
+			// both slice and string have len one pointer into the struct.
+			igen(nl, &n1, res);
+			n1.op = OREGISTER;	// was OINDREG
+			regalloc(&n2, types[TUINT32], &n1);
+			n1.op = OINDREG;
+			n1.type = types[TUINT32];
+			n1.xoffset = Array_nel;
+			gmove(&n1, &n2);
+			gmove(&n2, res);
+			regfree(&n1);
+			regfree(&n2);
+			break;
+		}
+		fatal("cgen: OLEN: unknown type %lT", nl->type);
+		break;
+
+	case OCAP:
+		if(istype(nl->type, TCHAN)) {
+			// chan has cap in the second 32-bit word.
+			// a zero pointer means zero length
+			regalloc(&n1, types[tptr], res);
+			cgen(nl, &n1);
+
+			nodconst(&n2, types[tptr], 0);
+			regalloc(&n3, n2.type, N);
+			gmove(&n2, &n3);
+			gcmp(optoas(OCMP, types[tptr]), &n1, &n3);
+			regfree(&n3);
+			p1 = gbranch(optoas(OEQ, types[tptr]), T);
+
+			n2 = n1;
+			n2.op = OINDREG;
+			n2.xoffset = 4;
+			n2.type = types[TINT32];
+			gmove(&n2, &n1);
+
+			patch(p1, pc);
+
+			gmove(&n1, res);
+			regfree(&n1);
+			break;
+		}
+		if(isslice(nl->type)) {
+			regalloc(&n1, types[tptr], res);
+			agen(nl, &n1);
+			n1.op = OINDREG;
+			n1.type = types[TUINT32];
+			n1.xoffset = Array_cap;
+			gmove(&n1, res);
+			regfree(&n1);
+			break;
+		}
+		fatal("cgen: OCAP: unknown type %lT", nl->type);
+		break;
+
+	case OADDR:
+		agen(nl, res);
+		break;
+
+	case OCALLMETH:
+		cgen_callmeth(n, 0);
+		cgen_callret(n, res);
+		break;
+
+	case OCALLINTER:
+		cgen_callinter(n, res, 0);
+		cgen_callret(n, res);
+		break;
+
+	case OCALLFUNC:
+		cgen_call(n, 0);
+		cgen_callret(n, res);
+		break;
+
+	case OMOD:
+	case ODIV:
+		a = optoas(n->op, nl->type);
+		goto abop;
+	}
+	goto ret;
+
+sbop:	// symmetric binary
+	if(nl->ullman < nr->ullman) {
+		r = nl;
+		nl = nr;
+		nr = r;
+	}
+
+abop:	// asymmetric binary
+	// TODO(kaib): use fewer registers here.
+	if(nl->ullman >= nr->ullman) {
+		regalloc(&n1, nl->type, res);
+		cgen(nl, &n1);
+		regalloc(&n2, nr->type, N);
+		cgen(nr, &n2);
+	} else {
+		regalloc(&n2, nr->type, N);
+		cgen(nr, &n2);
+		regalloc(&n1, nl->type, res);
+		cgen(nl, &n1);
+	}
+	gins(a, &n2, &n1);
+	gmove(&n1, res);
+	regfree(&n1);
+	regfree(&n2);
+	goto ret;
+
+flt:	// floating-point.
+	regalloc(&f0, nl->type, res);
+	if(nr != N)
+		goto flt2;
+
+	if(n->op == OMINUS) {
+		nr = nodintconst(-1);
+		convlit(&nr, n->type);
+		n->op = OMUL;
+		goto flt2;
+	}
+
+	// unary
+	cgen(nl, &f0);
+	if(n->op != OCONV && n->op != OPLUS)
+		gins(optoas(n->op, n->type), &f0, &f0);
+	gmove(&f0, res);
+	regfree(&f0);
+	goto ret;
+
+flt2:	// binary
+	if(nl->ullman >= nr->ullman) {
+		cgen(nl, &f0);
+		regalloc(&f1, n->type, N);
+		gmove(&f0, &f1);
+		cgen(nr, &f0);
+		gins(optoas(n->op, n->type), &f0, &f1);
+	} else {
+		cgen(nr, &f0);
+		regalloc(&f1, n->type, N);
+		cgen(nl, &f1);
+		gins(optoas(n->op, n->type), &f0, &f1);
+	}
+	gmove(&f1, res);
+	regfree(&f0);
+	regfree(&f1);
+	goto ret;
+
+ret:
+	;
+}
+
+/*
+ * generate array index into res.
+ * n might be any size; res is 32-bit.
+ * returns Prog* to patch to panic call.
+ */
+Prog*
+cgenindex(Node *n, Node *res)
+{
+	Node tmp, lo, hi, zero, n1, n2;
+
+	if(!is64(n->type)) {
+		cgen(n, res);
+		return nil;
+	}
+
+	tempname(&tmp, types[TINT64]);
+	cgen(n, &tmp);
+	split64(&tmp, &lo, &hi);
+	gmove(&lo, res);
+	if(debug['B']) {
+		splitclean();
+		return nil;
+	}
+	regalloc(&n1, types[TINT32], N);
+	regalloc(&n2, types[TINT32], N);
+	nodconst(&zero, types[TINT32], 0);
+	gmove(&hi, &n1);
+	gmove(&zero, &n2);
+	gcmp(ACMP, &n1, &n2);
+	regfree(&n2);
+	regfree(&n1);
+	splitclean();
+	return gbranch(ABNE, T);
+}
+
+/*
+ * generate:
+ *	res = &n;
+ */
+void
+agen(Node *n, Node *res)
+{
+	Node *nl, *nr;
+	Node n1, n2, n3, n4, n5, tmp;
+	Prog *p1, *p2;
+	uint32 w;
+	uint64 v;
+	int r;
+
+	if(debug['g']) {
+		dump("\nagen-res", res);
+		dump("agen-r", n);
+	}
+	if(n == N || n->type == T || res == N || res->type == T)
+		fatal("agen");
+
+	while(n->op == OCONVNOP)
+		n = n->left;
+
+	if(n->addable) {
+		memset(&n1, 0, sizeof n1);
+		n1.op = OADDR;
+		n1.left = n;
+		regalloc(&n2, types[tptr], res);
+		gins(AMOVW, &n1, &n2);
+		gmove(&n2, res);
+		regfree(&n2);
+		goto ret;
+	}
+
+	nl = n->left;
+	nr = n->right;
+
+	switch(n->op) {
+	default:
+		fatal("agen: unknown op %N", n);
+		break;
+
+	case OCALLMETH:
+	case OCALLFUNC:
+		// Release res so that it is available for cgen_call.
+		// Pick it up again after the call.
+		r = -1;
+		if(n->ullman >= UINF) {
+			if(res->op == OREGISTER || res->op == OINDREG) {
+				r = res->val.u.reg;
+				reg[r]--;
+			}
+		}
+		if(n->op == OCALLMETH)
+			cgen_callmeth(n, 0);
+		else
+			cgen_call(n, 0);
+		if(r >= 0)
+			reg[r]++;
+		cgen_aret(n, res);
+		break;
+
+	case OCALLINTER:
+		cgen_callinter(n, res, 0);
+		cgen_aret(n, res);
+		break;
+
+	case OINDEX:
+		p2 = nil;  // to be patched to panicindex.
+		w = n->type->width;
+		if(nr->addable) {
+			if(!isconst(nr, CTINT))
+				tempname(&tmp, types[TINT32]);
+			if(!isconst(nl, CTSTR))
+				agenr(nl, &n3, res);
+			if(!isconst(nr, CTINT)) {
+				p2 = cgenindex(nr, &tmp);
+				regalloc(&n1, tmp.type, N);
+				gmove(&tmp, &n1);
+			}
+		} else
+		if(nl->addable) {
+			if(!isconst(nr, CTINT)) {
+				tempname(&tmp, types[TINT32]);
+				p2 = cgenindex(nr, &tmp);
+				regalloc(&n1, tmp.type, N);
+				gmove(&tmp, &n1);
+			}
+			if(!isconst(nl, CTSTR)) {
+				regalloc(&n3, types[tptr], res);
+				agen(nl, &n3);
+			}
+		} else {
+			tempname(&tmp, types[TINT32]);
+			p2 = cgenindex(nr, &tmp);
+			nr = &tmp;
+			if(!isconst(nl, CTSTR))
+				agenr(nl, &n3, res);
+			regalloc(&n1, tmp.type, N);
+			gins(optoas(OAS, tmp.type), &tmp, &n1);
+		}
+
+		// &a is in &n3 (allocated in res)
+		// i is in &n1 (if not constant)
+		// w is width
+
+		// constant index
+		if(isconst(nr, CTINT)) {
+			if(isconst(nl, CTSTR))
+				fatal("constant string constant index");
+			v = mpgetfix(nr->val.u.xval);
+			if(isslice(nl->type) || nl->type->etype == TSTRING) {
+				if(!debug['B'] && !n->etype) {
+					n1 = n3;
+					n1.op = OINDREG;
+					n1.type = types[tptr];
+					n1.xoffset = Array_nel;
+					regalloc(&n4, n1.type, N);
+					cgen(&n1, &n4);
+					nodconst(&n2, types[TUINT32], v);
+					regalloc(&n5, n2.type, N);
+					gmove(&n2, &n5);
+					gcmp(optoas(OCMP, types[TUINT32]), &n4, &n5);
+					regfree(&n4);
+					regfree(&n5);
+					p1 = gbranch(optoas(OGT, types[TUINT32]), T);
+					ginscall(panicindex, 0);
+					patch(p1, pc);
+				}
+
+				n1 = n3;
+				n1.op = OINDREG;
+				n1.type = types[tptr];
+				n1.xoffset = Array_array;
+				gmove(&n1, &n3);
+			}
+
+			nodconst(&n2, types[tptr], v*w);
+			regalloc(&n4, n2.type, N);
+			gmove(&n2, &n4);
+			gins(optoas(OADD, types[tptr]), &n4, &n3);
+			regfree(&n4);
+
+			gmove(&n3, res);
+			regfree(&n3);
+			break;
+		}
+
+		regalloc(&n2, types[TINT32], &n1);			// i
+		gmove(&n1, &n2);
+		regfree(&n1);
+
+		if(!debug['B'] && !n->etype) {
+			// check bounds
+			regalloc(&n4, types[TUINT32], N);
+			if(isconst(nl, CTSTR)) {
+				nodconst(&n1, types[TUINT32], nl->val.u.sval->len);
+				gmove(&n1, &n4);
+			} else if(isslice(nl->type) || nl->type->etype == TSTRING) {
+				n1 = n3;
+				n1.op = OINDREG;
+				n1.type = types[tptr];
+				n1.xoffset = Array_nel;
+				cgen(&n1, &n4);
+			} else {
+				nodconst(&n1, types[TUINT32], nl->type->bound);
+				gmove(&n1, &n4);
+			}
+			gcmp(optoas(OCMP, types[TUINT32]), &n2, &n4);
+			regfree(&n4);
+			p1 = gbranch(optoas(OLT, types[TUINT32]), T);
+			if(p2)
+				patch(p2, pc);
+			ginscall(panicindex, 0);
+			patch(p1, pc);
+		}
+		
+		if(isconst(nl, CTSTR)) {
+			regalloc(&n3, types[tptr], res);
+			p1 = gins(AMOVW, N, &n3);
+			datastring(nl->val.u.sval->s, nl->val.u.sval->len, &p1->from);
+			p1->from.type = D_CONST;
+		} else
+		if(isslice(nl->type) || nl->type->etype == TSTRING) {
+			n1 = n3;
+			n1.op = OINDREG;
+			n1.type = types[tptr];
+			n1.xoffset = Array_array;
+			gmove(&n1, &n3);
+		}
+
+		if(w == 0) {
+			// nothing to do
+		} else if(w == 1 || w == 2 || w == 4 || w == 8) {
+			memset(&n4, 0, sizeof n4);
+			n4.op = OADDR;
+			n4.left = &n2;
+			cgen(&n4, &n3);
+			if (w == 1)
+				gins(AADD, &n2, &n3);
+			else if(w == 2)
+				gshift(AADD, &n2, SHIFT_LL, 1, &n3);
+			else if(w == 4)
+				gshift(AADD, &n2, SHIFT_LL, 2, &n3);
+			else if(w == 8)
+				gshift(AADD, &n2, SHIFT_LL, 3, &n3);	
+		} else {
+			regalloc(&n4, types[TUINT32], N);
+			nodconst(&n1, types[TUINT32], w);
+			gmove(&n1, &n4);
+			gins(optoas(OMUL, types[TUINT32]), &n4, &n2);
+			gins(optoas(OADD, types[tptr]), &n2, &n3);
+			regfree(&n4);
+			gmove(&n3, res);
+		}
+
+		gmove(&n3, res);
+		regfree(&n2);
+		regfree(&n3);
+		break;
+
+	case ONAME:
+		// should only get here with names in this func.
+		if(n->funcdepth > 0 && n->funcdepth != funcdepth) {
+			dump("bad agen", n);
+			fatal("agen: bad ONAME funcdepth %d != %d",
+				n->funcdepth, funcdepth);
+		}
+
+		// should only get here for heap vars or paramref
+		if(!(n->class & PHEAP) && n->class != PPARAMREF) {
+			dump("bad agen", n);
+			fatal("agen: bad ONAME class %#x", n->class);
+		}
+		cgen(n->heapaddr, res);
+		if(n->xoffset != 0) {
+			nodconst(&n1, types[TINT32], n->xoffset);
+			regalloc(&n2, n1.type, N);
+			regalloc(&n3, types[TINT32], N);
+			gmove(&n1, &n2);
+			gmove(res, &n3);
+			gins(optoas(OADD, types[tptr]), &n2, &n3);
+			gmove(&n3, res);
+			regfree(&n2);
+			regfree(&n3);
+		}
+		break;
+
+	case OIND:
+		cgen(nl, res);
+		break;
+
+	case ODOT:
+		agen(nl, res);
+		if(n->xoffset != 0) {
+			nodconst(&n1, types[TINT32], n->xoffset);
+			regalloc(&n2, n1.type, N);
+			regalloc(&n3, types[TINT32], N);
+			gmove(&n1, &n2);
+			gmove(res, &n3);
+			gins(optoas(OADD, types[tptr]), &n2, &n3);
+			gmove(&n3, res);
+			regfree(&n2);
+			regfree(&n3);
+		}
+		break;
+
+	case ODOTPTR:
+		cgen(nl, res);
+		if(n->xoffset != 0) {
+			// explicit check for nil if struct is large enough
+			// that we might derive too big a pointer.
+			if(nl->type->type->width >= unmappedzero) {
+				regalloc(&n1, types[tptr], N);
+				gmove(res, &n1);
+				p1 = gins(AMOVW, &n1, &n1);
+				p1->from.type = D_OREG;
+				p1->from.offset = 0;
+				regfree(&n1);
+			}
+			nodconst(&n1, types[TINT32], n->xoffset);
+			regalloc(&n2, n1.type, N);
+			regalloc(&n3, types[tptr], N);
+			gmove(&n1, &n2);
+			gmove(res, &n3);
+			gins(optoas(OADD, types[tptr]), &n2, &n3);
+			gmove(&n3, res);
+			regfree(&n2);
+			regfree(&n3);
+		}
+		break;
+	}
+
+ret:
+	;
+}
+
+/*
+ * generate:
+ *	newreg = &n;
+ *	res = newreg
+ *
+ * on exit, a has been changed to be *newreg.
+ * caller must regfree(a).
+ */
+void
+igen(Node *n, Node *a, Node *res)
+{
+	regalloc(a, types[tptr], res);
+	agen(n, a);
+	a->op = OINDREG;
+	a->type = n->type;
+}
+
+/*
+ * generate:
+ *	newreg = &n;
+ *
+ * caller must regfree(a).
+ */
+void
+agenr(Node *n, Node *a, Node *res)
+{
+	regalloc(a, types[tptr], res);
+	agen(n, a);
+}
+
+void
+gencmp0(Node *n, Type *t, int o, Prog *to)
+{
+	Node n1, n2, n3;
+	int a;
+
+	regalloc(&n1, t, N);
+	cgen(n, &n1);
+	a = optoas(OCMP, t);
+	if(a != ACMP) {
+		nodconst(&n2, t, 0);
+		regalloc(&n3, t, N);
+		gmove(&n2, &n3);
+		gcmp(a, &n1, &n3);
+		regfree(&n3);
+	} else
+		gins(ATST, &n1, N);
+	a = optoas(o, t);
+	patch(gbranch(a, t), to);
+	regfree(&n1);
+}
+
+/*
+ * generate:
+ *	if(n == true) goto to;
+ */
+void
+bgen(Node *n, int true, Prog *to)
+{
+	int et, a;
+	Node *nl, *nr, *r;
+	Node n1, n2, n3, n4, tmp;
+	Prog *p1, *p2;
+
+	if(debug['g']) {
+		dump("\nbgen", n);
+	}
+
+	if(n == N)
+		n = nodbool(1);
+
+	if(n->ninit != nil)
+		genlist(n->ninit);
+
+	nl = n->left;
+	nr = n->right;
+
+	if(n->type == T) {
+		convlit(&n, types[TBOOL]);
+		if(n->type == T)
+			goto ret;
+	}
+
+	et = n->type->etype;
+	if(et != TBOOL) {
+		yyerror("cgen: bad type %T for %O", n->type, n->op);
+		patch(gins(AEND, N, N), to);
+		goto ret;
+	}
+	nl = N;
+	nr = N;
+
+	switch(n->op) {
+	default:
+		a = ONE;
+		if(!true)
+			a = OEQ;
+		gencmp0(n, n->type, a, to);
+		goto ret;
+
+	case OLITERAL:
+		// need to ask if it is bool?
+		if(!true == !n->val.u.bval)
+			patch(gbranch(AB, T), to);
+		goto ret;
+
+	case OANDAND:
+		if(!true)
+			goto caseor;
+
+	caseand:
+		p1 = gbranch(AB, T);
+		p2 = gbranch(AB, T);
+		patch(p1, pc);
+		bgen(n->left, !true, p2);
+		bgen(n->right, !true, p2);
+		p1 = gbranch(AB, T);
+		patch(p1, to);
+		patch(p2, pc);
+		goto ret;
+
+	case OOROR:
+		if(!true)
+			goto caseand;
+
+	caseor:
+		bgen(n->left, true, to);
+		bgen(n->right, true, to);
+		goto ret;
+
+	case OEQ:
+	case ONE:
+	case OLT:
+	case OGT:
+	case OLE:
+	case OGE:
+		nr = n->right;
+		if(nr == N || nr->type == T)
+			goto ret;
+
+	case ONOT:	// unary
+		nl = n->left;
+		if(nl == N || nl->type == T)
+			goto ret;
+	}
+
+	switch(n->op) {
+
+	case ONOT:
+		bgen(nl, !true, to);
+		goto ret;
+
+	case OEQ:
+	case ONE:
+	case OLT:
+	case OGT:
+	case OLE:
+	case OGE:
+		a = n->op;
+		if(!true) {
+			if(isfloat[nl->type->etype]) {
+				// brcom is not valid on floats when NaN is involved.
+				p1 = gbranch(AB, T);
+				p2 = gbranch(AB, T);
+				patch(p1, pc);
+				bgen(n, 1, p2);
+				patch(gbranch(AB, T), to);
+				patch(p2, pc);
+				goto ret;
+			}				
+			a = brcom(a);
+			true = !true;
+		}
+
+		// make simplest on right
+		if(nl->op == OLITERAL || (nl->ullman < UINF && nl->ullman < nr->ullman)) {
+			a = brrev(a);
+			r = nl;
+			nl = nr;
+			nr = r;
+		}
+
+		if(isslice(nl->type)) {
+			// only valid to cmp darray to literal nil
+			if((a != OEQ && a != ONE) || nr->op != OLITERAL) {
+				yyerror("illegal array comparison");
+				break;
+			}
+
+			regalloc(&n1, types[tptr], N);
+			agen(nl, &n1);
+			n2 = n1;
+			n2.op = OINDREG;
+			n2.xoffset = Array_array;
+			gencmp0(&n2, types[tptr], a, to);
+			regfree(&n1);
+			break;
+
+			a = optoas(a, types[tptr]);
+			regalloc(&n1, types[tptr], N);
+			regalloc(&n3, types[tptr], N);
+			regalloc(&n4, types[tptr], N);
+			agen(nl, &n1);
+			n2 = n1;
+			n2.op = OINDREG;
+			n2.xoffset = Array_array;
+			gmove(&n2, &n4);
+			nodconst(&tmp, types[tptr], 0);
+			gmove(&tmp, &n3);
+			gcmp(optoas(OCMP, types[tptr]), &n4, &n3);
+			patch(gbranch(a, types[tptr]), to);
+			regfree(&n4);
+			regfree(&n3);
+			regfree(&n1);
+			break;
+		}
+
+		if(isinter(nl->type)) {
+			// front end shold only leave cmp to literal nil
+			if((a != OEQ && a != ONE) || nr->op != OLITERAL) {
+				yyerror("illegal interface comparison");
+				break;
+			}
+
+			regalloc(&n1, types[tptr], N);
+			agen(nl, &n1);
+			n2 = n1;
+			n2.op = OINDREG;
+			n2.xoffset = 0;
+			gencmp0(&n2, types[tptr], a, to);
+			regfree(&n1);
+			break;
+
+			a = optoas(a, types[tptr]);
+			regalloc(&n1, types[tptr], N);
+			regalloc(&n3, types[tptr], N);
+			regalloc(&n4, types[tptr], N);
+			agen(nl, &n1);
+			n2 = n1;
+			n2.op = OINDREG;
+			n2.xoffset = 0;
+			gmove(&n2, &n4);
+			nodconst(&tmp, types[tptr], 0);
+			gmove(&tmp, &n3);
+			gcmp(optoas(OCMP, types[tptr]), &n4, &n3);
+			patch(gbranch(a, types[tptr]), to);
+			regfree(&n1);
+			regfree(&n3);
+			regfree(&n4);
+			break;
+		}
+
+		if(iscomplex[nl->type->etype]) {
+			complexbool(a, nl, nr, true, to);
+			break;
+		}
+
+		if(is64(nr->type)) {
+			if(!nl->addable) {
+				tempname(&n1, nl->type);
+				cgen(nl, &n1);
+				nl = &n1;
+			}
+			if(!nr->addable) {
+				tempname(&n2, nr->type);
+				cgen(nr, &n2);
+				nr = &n2;
+			}
+			cmp64(nl, nr, a, to);
+			break;
+		}
+
+		if(nr->op == OLITERAL) {
+			if(nr->val.ctype == CTINT &&  mpgetfix(nr->val.u.xval) == 0) {
+				gencmp0(nl, nl->type, a, to);
+				break;
+			}
+			if(nr->val.ctype == CTNIL) {
+				gencmp0(nl, nl->type, a, to);
+				break;
+			}
+		}
+
+		a = optoas(a, nr->type);
+
+		if(nr->ullman >= UINF) {
+			regalloc(&n1, nl->type, N);
+			cgen(nl, &n1);
+
+			tempname(&tmp, nl->type);
+			gmove(&n1, &tmp);
+			regfree(&n1);
+
+			regalloc(&n2, nr->type, N);
+			cgen(nr, &n2);
+
+			regalloc(&n1, nl->type, N);
+			cgen(&tmp, &n1);
+
+			gcmp(optoas(OCMP, nr->type), &n1, &n2);
+			patch(gbranch(a, nr->type), to);
+
+			regfree(&n1);
+			regfree(&n2);
+			break;
+		}
+
+		tempname(&n3, nl->type);
+		cgen(nl, &n3);
+
+		tempname(&tmp, nr->type);
+		cgen(nr, &tmp);
+
+		regalloc(&n1, nl->type, N);
+		gmove(&n3, &n1);
+
+		regalloc(&n2, nr->type, N);
+		gmove(&tmp, &n2);
+
+		gcmp(optoas(OCMP, nr->type), &n1, &n2);
+		if(isfloat[nl->type->etype]) {
+			p1 = gbranch(ABVS, nr->type);
+			patch(gbranch(a, nr->type), to);
+			if(n->op == ONE)
+				patch(p1, to);
+			else
+				patch(p1, pc);
+		} else {
+			patch(gbranch(a, nr->type), to);
+		}
+		regfree(&n1);
+		regfree(&n2);
+		break;
+	}
+	goto ret;
+
+ret:
+	;
+}
+
+/*
+ * n is on stack, either local variable
+ * or return value from function call.
+ * return n's offset from SP.
+ */
+int32
+stkof(Node *n)
+{
+	Type *t;
+	Iter flist;
+	int32 off;
+
+	switch(n->op) {
+	case OINDREG:
+		return n->xoffset;
+
+	case ODOT:
+		t = n->left->type;
+		if(isptr[t->etype])
+			break;
+		off = stkof(n->left);
+		if(off == -1000 || off == 1000)
+			return off;
+		return off + n->xoffset;
+
+	case OINDEX:
+		t = n->left->type;
+		if(!isfixedarray(t))
+			break;
+		off = stkof(n->left);
+		if(off == -1000 || off == 1000)
+			return off;
+		if(isconst(n->right, CTINT))
+			return off + t->type->width * mpgetfix(n->right->val.u.xval);
+		return 1000;
+		
+	case OCALLMETH:
+	case OCALLINTER:
+	case OCALLFUNC:
+		t = n->left->type;
+		if(isptr[t->etype])
+			t = t->type;
+
+		t = structfirst(&flist, getoutarg(t));
+		if(t != T)
+			return t->width + 4;	// correct for LR
+		break;
+	}
+
+	// botch - probably failing to recognize address
+	// arithmetic on the above. eg INDEX and DOT
+	return -1000;
+}
+
+/*
+ * block copy:
+ *	memmove(&res, &n, w);
+ * NB: character copy assumed little endian architecture
+ */
+void
+sgen(Node *n, Node *res, int32 w)
+{
+	Node dst, src, tmp, nend;
+	int32 c, odst, osrc;
+	int dir, align, op;
+	Prog *p, *ploop;
+
+	if(debug['g']) {
+		print("\nsgen w=%d\n", w);
+		dump("r", n);
+		dump("res", res);
+	}
+	if(w == 0)
+		return;
+	if(w < 0)
+		fatal("sgen copy %d", w);
+	if(n->ullman >= UINF && res->ullman >= UINF)
+		fatal("sgen UINF");
+	if(n->type == T)
+		fatal("sgen: missing type");
+
+	// determine alignment.
+	// want to avoid unaligned access, so have to use
+	// smaller operations for less aligned types.
+	// for example moving [4]byte must use 4 MOVB not 1 MOVW.
+	align = n->type->align;
+	op = 0;
+	switch(align) {
+	default:
+		fatal("sgen: invalid alignment %d for %T", align, n->type);
+	case 1:
+		op = AMOVB;
+		break;
+	case 2:
+		op = AMOVH;
+		break;
+	case 4:
+		op = AMOVW;
+		break;
+	}
+	if(w%align)
+		fatal("sgen: unaligned size %d (align=%d) for %T", w, align, n->type);
+	c = w / align;
+
+	// offset on the stack
+	osrc = stkof(n);
+	odst = stkof(res);
+	if(osrc != -1000 && odst != -1000 && (osrc == 1000 || odst == 1000)) {
+		// osrc and odst both on stack, and at least one is in
+		// an unknown position.  Could generate code to test
+		// for forward/backward copy, but instead just copy
+		// to a temporary location first.
+		tempname(&tmp, n->type);
+		sgen(n, &tmp, w);
+		sgen(&tmp, res, w);
+		return;
+	}
+	if(osrc%align != 0 || odst%align != 0)
+		fatal("sgen: unaligned offset src %d or dst %d (align %d)", osrc, odst, align);
+	// if we are copying forward on the stack and
+	// the src and dst overlap, then reverse direction
+	dir = align;
+	if(osrc < odst && odst < osrc+w)
+		dir = -dir;
+
+	regalloc(&dst, types[tptr], res);
+	if(n->ullman >= res->ullman) {
+		agen(n, &dst);	// temporarily use dst
+		regalloc(&src, types[tptr], N);
+		gins(AMOVW, &dst, &src);
+		agen(res, &dst);
+	} else {
+		agen(res, &dst);
+		regalloc(&src, types[tptr], N);
+		agen(n, &src);
+	}
+
+	regalloc(&tmp, types[TUINT32], N);
+
+	// set up end marker
+	memset(&nend, 0, sizeof nend);
+	if(c >= 4) {
+		regalloc(&nend, types[TUINT32], N);
+
+		p = gins(AMOVW, &src, &nend);
+		p->from.type = D_CONST;
+		if(dir < 0)
+			p->from.offset = dir;
+		else
+			p->from.offset = w;
+	}
+
+	// move src and dest to the end of block if necessary
+	if(dir < 0) {
+		p = gins(AMOVW, &src, &src);
+		p->from.type = D_CONST;
+		p->from.offset = w + dir;
+
+		p = gins(AMOVW, &dst, &dst);
+		p->from.type = D_CONST;
+		p->from.offset = w + dir;
+	}
+	
+	// move
+	if(c >= 4) {
+		p = gins(op, &src, &tmp);
+		p->from.type = D_OREG;
+		p->from.offset = dir;
+		p->scond |= C_PBIT;
+		ploop = p;
+
+		p = gins(op, &tmp, &dst);
+		p->to.type = D_OREG;
+		p->to.offset = dir;
+		p->scond |= C_PBIT;
+
+		p = gins(ACMP, &src, N);
+		raddr(&nend, p);
+
+		patch(gbranch(ABNE, T), ploop);
+ 		regfree(&nend);
+	} else {
+		while(c-- > 0) {
+			p = gins(op, &src, &tmp);
+			p->from.type = D_OREG;
+			p->from.offset = dir;
+			p->scond |= C_PBIT;
+			ploop = p;
+	
+			p = gins(op, &tmp, &dst);
+			p->to.type = D_OREG;
+			p->to.offset = dir;
+			p->scond |= C_PBIT;
+		}
+	}
+
+	regfree(&dst);
+	regfree(&src);
+	regfree(&tmp);
+}
diff --git a/src/cmd/5g/cgen64.c b/src/cmd/5g/cgen64.c
new file mode 100644
index 000000000..b56df765b
--- /dev/null
+++ b/src/cmd/5g/cgen64.c
@@ -0,0 +1,716 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "gg.h"
+
+/*
+ * attempt to generate 64-bit
+ *	res = n
+ * return 1 on success, 0 if op not handled.
+ */
+void
+cgen64(Node *n, Node *res)
+{
+	Node t1, t2, *l, *r;
+	Node lo1, lo2, hi1, hi2;
+	Node al, ah, bl, bh, cl, ch, s, n1, creg;
+	Prog *p1, *p2, *p3, *p4, *p5, *p6;
+
+	uint64 v;
+
+	if(res->op != OINDREG && res->op != ONAME) {
+		dump("n", n);
+		dump("res", res);
+		fatal("cgen64 %O of %O", n->op, res->op);
+	}
+
+	l = n->left;
+	if(!l->addable) {
+		tempname(&t1, l->type);
+		cgen(l, &t1);
+		l = &t1;
+	}
+
+	split64(l, &lo1, &hi1);
+	switch(n->op) {
+	default:
+		fatal("cgen64 %O", n->op);
+
+	case OMINUS:
+		split64(res, &lo2, &hi2);
+
+		regalloc(&t1, lo1.type, N);
+		regalloc(&al, lo1.type, N);
+		regalloc(&ah, hi1.type, N);
+
+		gins(AMOVW, &lo1, &al);
+		gins(AMOVW, &hi1, &ah);
+
+		gmove(ncon(0), &t1);
+		p1 = gins(ASUB, &al, &t1);
+		p1->scond |= C_SBIT;
+		gins(AMOVW, &t1, &lo2);
+
+		gmove(ncon(0), &t1);
+		gins(ASBC, &ah, &t1);
+		gins(AMOVW, &t1, &hi2);
+
+		regfree(&t1);
+		regfree(&al);
+		regfree(&ah);
+		splitclean();
+		splitclean();
+		return;
+
+	case OCOM:
+		regalloc(&t1, lo1.type, N);
+		gmove(ncon(-1), &t1);
+
+		split64(res, &lo2, &hi2);
+		regalloc(&n1, lo1.type, N);
+
+		gins(AMOVW, &lo1, &n1);
+		gins(AEOR, &t1, &n1);
+		gins(AMOVW, &n1, &lo2);
+
+		gins(AMOVW, &hi1, &n1);
+		gins(AEOR, &t1, &n1);
+		gins(AMOVW, &n1, &hi2);
+
+		regfree(&t1);
+		regfree(&n1);
+		splitclean();
+		splitclean();
+		return;
+
+	case OADD:
+	case OSUB:
+	case OMUL:
+	case OLSH:
+	case ORSH:
+	case OAND:
+	case OOR:
+	case OXOR:
+		// binary operators.
+		// common setup below.
+		break;
+	}
+
+	// setup for binary operators
+	r = n->right;
+	if(r != N && !r->addable) {
+		tempname(&t2, r->type);
+		cgen(r, &t2);
+		r = &t2;
+	}
+	if(is64(r->type))
+		split64(r, &lo2, &hi2);
+
+	regalloc(&al, lo1.type, N);
+	regalloc(&ah, hi1.type, N);
+
+	// Do op.  Leave result in ah:al.
+	switch(n->op) {
+	default:
+		fatal("cgen64: not implemented: %N\n", n);
+
+	case OADD:
+		// TODO: Constants
+		regalloc(&bl, types[TPTR32], N);
+		regalloc(&bh, types[TPTR32], N);
+		gins(AMOVW, &hi1, &ah);
+		gins(AMOVW, &lo1, &al);
+		gins(AMOVW, &hi2, &bh);
+		gins(AMOVW, &lo2, &bl);
+		p1 = gins(AADD, &bl, &al);
+		p1->scond |= C_SBIT;
+		gins(AADC, &bh, &ah);
+		regfree(&bl);
+		regfree(&bh);
+		break;
+
+	case OSUB:
+		// TODO: Constants.
+		regalloc(&bl, types[TPTR32], N);
+		regalloc(&bh, types[TPTR32], N);
+		gins(AMOVW, &lo1, &al);
+		gins(AMOVW, &hi1, &ah);
+		gins(AMOVW, &lo2, &bl);
+		gins(AMOVW, &hi2, &bh);
+		p1 = gins(ASUB, &bl, &al);
+		p1->scond |= C_SBIT;
+		gins(ASBC, &bh, &ah);
+		regfree(&bl);
+		regfree(&bh);
+		break;
+
+	case OMUL:
+		// TODO(kaib): this can be done with 4 regs and does not need 6
+		regalloc(&bl, types[TPTR32], N);
+		regalloc(&bh, types[TPTR32], N);
+		regalloc(&cl, types[TPTR32], N);
+		regalloc(&ch, types[TPTR32], N);
+
+		// load args into bh:bl and bh:bl.
+		gins(AMOVW, &hi1, &bh);
+		gins(AMOVW, &lo1, &bl);
+		gins(AMOVW, &hi2, &ch);
+		gins(AMOVW, &lo2, &cl);
+
+		// bl * cl -> ah al
+		p1 = gins(AMULLU, N, N);
+		p1->from.type = D_REG;
+		p1->from.reg = bl.val.u.reg;
+		p1->reg = cl.val.u.reg;
+		p1->to.type = D_REGREG;
+		p1->to.reg = ah.val.u.reg;
+		p1->to.offset = al.val.u.reg;
+//print("%P\n", p1);
+
+		// bl * ch + ah -> ah
+		p1 = gins(AMULA, N, N);
+		p1->from.type = D_REG;
+		p1->from.reg = bl.val.u.reg;
+		p1->reg = ch.val.u.reg;
+		p1->to.type = D_REGREG;
+		p1->to.reg = ah.val.u.reg;
+		p1->to.offset = ah.val.u.reg;
+//print("%P\n", p1);
+
+		// bh * cl + ah -> ah
+		p1 = gins(AMULA, N, N);
+		p1->from.type = D_REG;
+		p1->from.reg = bh.val.u.reg;
+		p1->reg = cl.val.u.reg;
+		p1->to.type = D_REGREG;
+		p1->to.reg = ah.val.u.reg;
+		p1->to.offset = ah.val.u.reg;
+//print("%P\n", p1);
+
+		regfree(&bh);
+		regfree(&bl);
+		regfree(&ch);
+		regfree(&cl);
+
+		break;
+
+	case OLSH:
+		regalloc(&bl, lo1.type, N);
+		regalloc(&bh, hi1.type, N);
+		gins(AMOVW, &hi1, &bh);
+		gins(AMOVW, &lo1, &bl);
+
+		if(r->op == OLITERAL) {
+			v = mpgetfix(r->val.u.xval);
+			if(v >= 64) {
+				// TODO(kaib): replace with gins(AMOVW, nodintconst(0), &al)
+				// here and below (verify it optimizes to EOR)
+				gins(AEOR, &al, &al);
+				gins(AEOR, &ah, &ah);
+			} else
+			if(v > 32) {
+				gins(AEOR, &al, &al);
+				//	MOVW	bl<<(v-32), ah
+				gshift(AMOVW, &bl, SHIFT_LL, (v-32), &ah);
+			} else
+			if(v == 32) {
+				gins(AEOR, &al, &al);
+				gins(AMOVW, &bl, &ah);
+			} else
+			if(v > 0) {
+				//	MOVW	bl<<v, al
+				gshift(AMOVW, &bl, SHIFT_LL, v, &al);
+
+				//	MOVW	bh<<v, ah
+				gshift(AMOVW, &bh, SHIFT_LL, v, &ah);
+
+				//	OR		bl>>(32-v), ah
+				gshift(AORR, &bl, SHIFT_LR, 32-v, &ah);
+			} else {
+				gins(AMOVW, &bl, &al);
+				gins(AMOVW, &bh, &ah);
+			}
+			goto olsh_break;
+		}
+
+		regalloc(&s, types[TUINT32], N);
+		regalloc(&creg, types[TUINT32], N);
+		if (is64(r->type)) {
+			// shift is >= 1<<32
+			split64(r, &cl, &ch);
+			gmove(&ch, &s);
+			p1 = gins(ATST, &s, N);
+			p6 = gbranch(ABNE, T);
+			gmove(&cl, &s);
+			splitclean();
+		} else {
+			gmove(r, &s);
+			p6 = P;
+		}
+		p1 = gins(ATST, &s, N);
+
+		// shift == 0
+		p1 = gins(AMOVW, &bl, &al);
+		p1->scond = C_SCOND_EQ;
+		p1 = gins(AMOVW, &bh, &ah);
+		p1->scond = C_SCOND_EQ;
+		p2 = gbranch(ABEQ, T);
+
+		// shift is < 32
+		nodconst(&n1, types[TUINT32], 32);
+		gmove(&n1, &creg);
+		gcmp(ACMP, &s, &creg);
+
+		//	MOVW.LO		bl<<s, al
+		p1 = gregshift(AMOVW, &bl, SHIFT_LL, &s, &al);
+		p1->scond = C_SCOND_LO;
+
+		//	MOVW.LO		bh<<s, ah
+		p1 = gregshift(AMOVW, &bh, SHIFT_LL, &s, &ah);
+		p1->scond = C_SCOND_LO;
+
+		//	SUB.LO		s, creg
+		p1 = gins(ASUB, &s, &creg);
+		p1->scond = C_SCOND_LO;
+
+		//	OR.LO		bl>>creg, ah
+		p1 = gregshift(AORR, &bl, SHIFT_LR, &creg, &ah);
+		p1->scond = C_SCOND_LO;
+
+		//	BLO	end
+		p3 = gbranch(ABLO, T);
+
+		// shift == 32
+		p1 = gins(AEOR, &al, &al);
+		p1->scond = C_SCOND_EQ;
+		p1 = gins(AMOVW, &bl, &ah);
+		p1->scond = C_SCOND_EQ;
+		p4 = gbranch(ABEQ, T);
+
+		// shift is < 64
+		nodconst(&n1, types[TUINT32], 64);
+		gmove(&n1, &creg);
+		gcmp(ACMP, &s, &creg);
+
+		//	EOR.LO	al, al
+		p1 = gins(AEOR, &al, &al);
+		p1->scond = C_SCOND_LO;
+
+		//	MOVW.LO		creg>>1, creg
+		p1 = gshift(AMOVW, &creg, SHIFT_LR, 1, &creg);
+		p1->scond = C_SCOND_LO;
+
+		//	SUB.LO		creg, s
+		p1 = gins(ASUB, &creg, &s);
+		p1->scond = C_SCOND_LO;
+
+		//	MOVW	bl<<s, ah
+		p1 = gregshift(AMOVW, &bl, SHIFT_LL, &s, &ah);
+		p1->scond = C_SCOND_LO;
+
+		p5 = gbranch(ABLO, T);
+
+		// shift >= 64
+		if (p6 != P) patch(p6, pc);
+		gins(AEOR, &al, &al);
+		gins(AEOR, &ah, &ah);
+
+		patch(p2, pc);
+		patch(p3, pc);
+		patch(p4, pc);
+		patch(p5, pc);
+		regfree(&s);
+		regfree(&creg);
+
+olsh_break:
+		regfree(&bl);
+		regfree(&bh);
+		break;
+
+
+	case ORSH:
+		regalloc(&bl, lo1.type, N);
+		regalloc(&bh, hi1.type, N);
+		gins(AMOVW, &hi1, &bh);
+		gins(AMOVW, &lo1, &bl);
+
+		if(r->op == OLITERAL) {
+			v = mpgetfix(r->val.u.xval);
+			if(v >= 64) {
+				if(bh.type->etype == TINT32) {
+					//	MOVW	bh->31, al
+					gshift(AMOVW, &bh, SHIFT_AR, 31, &al);
+
+					//	MOVW	bh->31, ah
+					gshift(AMOVW, &bh, SHIFT_AR, 31, &ah);
+				} else {
+					gins(AEOR, &al, &al);
+					gins(AEOR, &ah, &ah);
+				}
+			} else
+			if(v > 32) {
+				if(bh.type->etype == TINT32) {
+					//	MOVW	bh->(v-32), al
+					gshift(AMOVW, &bh, SHIFT_AR, v-32, &al);
+
+					//	MOVW	bh->31, ah
+					gshift(AMOVW, &bh, SHIFT_AR, 31, &ah);
+				} else {
+					//	MOVW	bh>>(v-32), al
+					gshift(AMOVW, &bh, SHIFT_LR, v-32, &al);
+					gins(AEOR, &ah, &ah);
+				}
+			} else
+			if(v == 32) {
+				gins(AMOVW, &bh, &al);
+				if(bh.type->etype == TINT32) {
+					//	MOVW	bh->31, ah
+					gshift(AMOVW, &bh, SHIFT_AR, 31, &ah);
+				} else {
+					gins(AEOR, &ah, &ah);
+				}
+			} else
+			if( v > 0) {
+				//	MOVW	bl>>v, al
+				gshift(AMOVW, &bl, SHIFT_LR, v, &al);
+	
+				//	OR		bh<<(32-v), al
+				gshift(AORR, &bh, SHIFT_LL, 32-v, &al);
+
+				if(bh.type->etype == TINT32) {
+					//	MOVW	bh->v, ah
+					gshift(AMOVW, &bh, SHIFT_AR, v, &ah);
+				} else {
+					//	MOVW	bh>>v, ah
+					gshift(AMOVW, &bh, SHIFT_LR, v, &ah);
+				}
+			} else {
+				gins(AMOVW, &bl, &al);
+				gins(AMOVW, &bh, &ah);
+			}
+			goto orsh_break;
+		}
+
+		regalloc(&s, types[TUINT32], N);
+		regalloc(&creg, types[TUINT32], N);
+		if(is64(r->type)) {
+			// shift is >= 1<<32
+			split64(r, &cl, &ch);
+			gmove(&ch, &s);
+			gins(ATST, &s, N);
+			if(bh.type->etype == TINT32)
+				p1 = gshift(AMOVW, &bh, SHIFT_AR, 31, &ah);
+			else
+				p1 = gins(AEOR, &ah, &ah);
+			p1->scond = C_SCOND_NE;
+			p6 = gbranch(ABNE, T);
+			gmove(&cl, &s);
+			splitclean();
+		} else {
+			gmove(r, &s);
+			p6 = P;
+		}
+		p1 = gins(ATST, &s, N);
+
+		// shift == 0
+		p1 = gins(AMOVW, &bl, &al);
+		p1->scond = C_SCOND_EQ;
+		p1 = gins(AMOVW, &bh, &ah);
+		p1->scond = C_SCOND_EQ;
+		p2 = gbranch(ABEQ, T);
+
+		// check if shift is < 32
+		nodconst(&n1, types[TUINT32], 32);
+		gmove(&n1, &creg);
+		gcmp(ACMP, &s, &creg);
+
+		//	MOVW.LO		bl>>s, al
+		p1 = gregshift(AMOVW, &bl, SHIFT_LR, &s, &al);
+		p1->scond = C_SCOND_LO;
+
+		//	SUB.LO		s,creg
+		p1 = gins(ASUB, &s, &creg);
+		p1->scond = C_SCOND_LO;
+
+		//	OR.LO		bh<<(32-s), al
+		p1 = gregshift(AORR, &bh, SHIFT_LL, &creg, &al);
+		p1->scond = C_SCOND_LO;
+
+		if(bh.type->etype == TINT32) {
+			//	MOVW	bh->s, ah
+			p1 = gregshift(AMOVW, &bh, SHIFT_AR, &s, &ah);
+		} else {
+			//	MOVW	bh>>s, ah
+			p1 = gregshift(AMOVW, &bh, SHIFT_LR, &s, &ah);
+		}
+		p1->scond = C_SCOND_LO;
+
+		//	BLO	end
+		p3 = gbranch(ABLO, T);
+
+		// shift == 32
+		p1 = gins(AMOVW, &bh, &al);
+		p1->scond = C_SCOND_EQ;
+		if(bh.type->etype == TINT32)
+			p1 = gshift(AMOVW, &bh, SHIFT_AR, 31, &ah);
+		else
+			p1 = gins(AEOR, &ah, &ah);
+		p4 = gbranch(ABEQ, T);
+
+		// check if shift is < 64
+		nodconst(&n1, types[TUINT32], 64);
+		gmove(&n1, &creg);
+		gcmp(ACMP, &s, &creg);
+
+		//	MOVW.LO		creg>>1, creg
+		p1 = gshift(AMOVW, &creg, SHIFT_LR, 1, &creg);
+		p1->scond = C_SCOND_LO;
+
+		//	SUB.LO		creg, s
+		p1 = gins(ASUB, &creg, &s);
+		p1->scond = C_SCOND_LO;
+
+		if(bh.type->etype == TINT32) {
+			//	MOVW	bh->(s-32), al
+			p1 = gregshift(AMOVW, &bh, SHIFT_AR, &s, &al);
+			p1->scond = C_SCOND_LO;
+		} else {
+			//	MOVW	bh>>(v-32), al
+			p1 = gregshift(AMOVW, &bh, SHIFT_LR, &s, &al);
+			p1->scond = C_SCOND_LO;
+		}
+
+		//	BLO	end
+		p5 = gbranch(ABLO, T);
+
+		// s >= 64
+		if(p6 != P)
+			patch(p6, pc);
+		if(bh.type->etype == TINT32) {
+			//	MOVW	bh->31, al
+			gshift(AMOVW, &bh, SHIFT_AR, 31, &al);
+		} else {
+			gins(AEOR, &al, &al);
+		}
+
+		patch(p2, pc);
+		patch(p3, pc);
+		patch(p4, pc);
+		patch(p5, pc);
+		regfree(&s);
+		regfree(&creg);
+
+
+orsh_break:
+		regfree(&bl);
+		regfree(&bh);
+		break;
+
+	case OXOR:
+	case OAND:
+	case OOR:
+		// TODO(kaib): literal optimizations
+		// make constant the right side (it usually is anyway).
+//		if(lo1.op == OLITERAL) {
+//			nswap(&lo1, &lo2);
+//			nswap(&hi1, &hi2);
+//		}
+//		if(lo2.op == OLITERAL) {
+//			// special cases for constants.
+//			lv = mpgetfix(lo2.val.u.xval);
+//			hv = mpgetfix(hi2.val.u.xval);
+//			splitclean();	// right side
+//			split64(res, &lo2, &hi2);
+//			switch(n->op) {
+//			case OXOR:
+//				gmove(&lo1, &lo2);
+//				gmove(&hi1, &hi2);
+//				switch(lv) {
+//				case 0:
+//					break;
+//				case 0xffffffffu:
+//					gins(ANOTL, N, &lo2);
+//					break;
+//				default:
+//					gins(AXORL, ncon(lv), &lo2);
+//					break;
+//				}
+//				switch(hv) {
+//				case 0:
+//					break;
+//				case 0xffffffffu:
+//					gins(ANOTL, N, &hi2);
+//					break;
+//				default:
+//					gins(AXORL, ncon(hv), &hi2);
+//					break;
+//				}
+//				break;
+
+//			case OAND:
+//				switch(lv) {
+//				case 0:
+//					gins(AMOVL, ncon(0), &lo2);
+//					break;
+//				default:
+//					gmove(&lo1, &lo2);
+//					if(lv != 0xffffffffu)
+//						gins(AANDL, ncon(lv), &lo2);
+//					break;
+//				}
+//				switch(hv) {
+//				case 0:
+//					gins(AMOVL, ncon(0), &hi2);
+//					break;
+//				default:
+//					gmove(&hi1, &hi2);
+//					if(hv != 0xffffffffu)
+//						gins(AANDL, ncon(hv), &hi2);
+//					break;
+//				}
+//				break;
+
+//			case OOR:
+//				switch(lv) {
+//				case 0:
+//					gmove(&lo1, &lo2);
+//					break;
+//				case 0xffffffffu:
+//					gins(AMOVL, ncon(0xffffffffu), &lo2);
+//					break;
+//				default:
+//					gmove(&lo1, &lo2);
+//					gins(AORL, ncon(lv), &lo2);
+//					break;
+//				}
+//				switch(hv) {
+//				case 0:
+//					gmove(&hi1, &hi2);
+//					break;
+//				case 0xffffffffu:
+//					gins(AMOVL, ncon(0xffffffffu), &hi2);
+//					break;
+//				default:
+//					gmove(&hi1, &hi2);
+//					gins(AORL, ncon(hv), &hi2);
+//					break;
+//				}
+//				break;
+//			}
+//			splitclean();
+//			splitclean();
+//			goto out;
+//		}
+		regalloc(&n1, lo1.type, N);
+		gins(AMOVW, &lo1, &al);
+		gins(AMOVW, &hi1, &ah);
+		gins(AMOVW, &lo2, &n1);
+		gins(optoas(n->op, lo1.type), &n1, &al);
+		gins(AMOVW, &hi2, &n1);
+		gins(optoas(n->op, lo1.type), &n1, &ah);
+		regfree(&n1);
+		break;
+	}
+	if(is64(r->type))
+		splitclean();
+	splitclean();
+
+	split64(res, &lo1, &hi1);
+	gins(AMOVW, &al, &lo1);
+	gins(AMOVW, &ah, &hi1);
+	splitclean();
+
+//out:
+	regfree(&al);
+	regfree(&ah);
+}
+
+/*
+ * generate comparison of nl, nr, both 64-bit.
+ * nl is memory; nr is constant or memory.
+ */
+void
+cmp64(Node *nl, Node *nr, int op, Prog *to)
+{
+	Node lo1, hi1, lo2, hi2, r1, r2;
+	Prog *br;
+	Type *t;
+
+	split64(nl, &lo1, &hi1);
+	split64(nr, &lo2, &hi2);
+
+	// compare most significant word;
+	// if they differ, we're done.
+	t = hi1.type;
+	regalloc(&r1, types[TINT32], N);
+	regalloc(&r2, types[TINT32], N);
+	gins(AMOVW, &hi1, &r1);
+	gins(AMOVW, &hi2, &r2);
+	gcmp(ACMP, &r1, &r2);
+	regfree(&r1);
+	regfree(&r2);
+
+	br = P;
+	switch(op) {
+	default:
+		fatal("cmp64 %O %T", op, t);
+	case OEQ:
+		// cmp hi
+		// bne L
+		// cmp lo
+		// beq to
+		// L:
+		br = gbranch(ABNE, T);
+		break;
+	case ONE:
+		// cmp hi
+		// bne to
+		// cmp lo
+		// bne to
+		patch(gbranch(ABNE, T), to);
+		break;
+	case OGE:
+	case OGT:
+		// cmp hi
+		// bgt to
+		// blt L
+		// cmp lo
+		// bge to (or bgt to)
+		// L:
+		patch(gbranch(optoas(OGT, t), T), to);
+		br = gbranch(optoas(OLT, t), T);
+		break;
+	case OLE:
+	case OLT:
+		// cmp hi
+		// blt to
+		// bgt L
+		// cmp lo
+		// ble to (or jlt to)
+		// L:
+		patch(gbranch(optoas(OLT, t), T), to);
+		br = gbranch(optoas(OGT, t), T);
+		break;
+	}
+
+	// compare least significant word
+	t = lo1.type;
+	regalloc(&r1, types[TINT32], N);
+	regalloc(&r2, types[TINT32], N);
+	gins(AMOVW, &lo1, &r1);
+	gins(AMOVW, &lo2, &r2);
+	gcmp(ACMP, &r1, &r2);
+	regfree(&r1);
+	regfree(&r2);
+
+	// jump again
+	patch(gbranch(optoas(op, t), T), to);
+
+	// point first branch down here if appropriate
+	if(br != P)
+		patch(br, pc);
+
+	splitclean();
+	splitclean();
+}
diff --git a/src/cmd/5g/doc.go b/src/cmd/5g/doc.go
new file mode 100644
index 000000000..e86013bdd
--- /dev/null
+++ b/src/cmd/5g/doc.go
@@ -0,0 +1,15 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+
+5g is the version of the gc compiler for the ARM.
+The $GOARCH for these tools is arm.
+
+It reads .go files and outputs .5 files. The flags are documented in ../gc/doc.go.
+
+There is no instruction optimizer, so the -N flag is a no-op.
+
+*/
+package documentation
diff --git a/src/cmd/5g/galign.c b/src/cmd/5g/galign.c
new file mode 100644
index 000000000..12766102f
--- /dev/null
+++ b/src/cmd/5g/galign.c
@@ -0,0 +1,39 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "gg.h"
+
+int	thechar	= '5';
+char*	thestring	= "arm";
+
+vlong MAXWIDTH = (1LL<<32) - 1;
+
+/*
+ * go declares several platform-specific type aliases:
+ * int, uint, float, and uintptr
+ */
+Typedef	typedefs[] =
+{
+	"int",		TINT,		TINT32,
+	"uint",		TUINT,		TUINT32,
+	"uintptr",	TUINTPTR,	TUINT32,
+	0
+};
+
+void
+betypeinit(void)
+{
+	widthptr = 4;
+
+	zprog.link = P;
+	zprog.as = AGOK;
+	zprog.scond = C_SCOND_NONE;
+	zprog.reg = NREG;
+	zprog.from.type = D_NONE;
+	zprog.from.name = D_NONE;
+	zprog.from.reg = NREG;
+	zprog.to = zprog.from;
+
+	listinit();
+}
diff --git a/src/cmd/5g/gg.h b/src/cmd/5g/gg.h
new file mode 100644
index 000000000..ce4558e21
--- /dev/null
+++ b/src/cmd/5g/gg.h
@@ -0,0 +1,171 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include <u.h>
+#include <libc.h>
+
+#include "../gc/go.h"
+#include "../5l/5.out.h"
+
+#ifndef	EXTERN
+#define EXTERN	extern
+#endif
+
+typedef	struct	Addr	Addr;
+
+struct	Addr
+{
+	int32	offset;
+	int32	offset2;
+	double	dval;
+	Prog*	branch;
+	char	sval[NSNAME];
+
+	Sym*	sym;
+	Node*	node;
+	int	width;
+	uchar	type;
+	char	name;
+	uchar	reg;
+	char pun;
+	uchar	etype;
+};
+#define	A	((Addr*)0)
+
+struct	Prog
+{
+	short	as;		// opcode
+	uint32	loc;		// pc offset in this func
+	uint32	lineno;		// source line that generated this
+	Addr	from;		// src address
+	Addr	to;		// dst address
+	Prog*	link;		// next instruction in this func
+	void*	regp;		// points to enclosing Reg struct
+	uchar	reg;		// doubles as width in DATA op
+	uchar	scond;
+};
+
+#define REGALLOC_R0 0
+#define REGALLOC_RMAX REGEXT
+#define REGALLOC_F0 (REGALLOC_RMAX+1)
+#define REGALLOC_FMAX (REGALLOC_F0 + FREGEXT)
+
+EXTERN	Biobuf*	bout;
+EXTERN	int32	dynloc;
+EXTERN	uchar	reg[REGALLOC_FMAX+1];
+EXTERN	int32	pcloc;		// instruction counter
+EXTERN	Strlit	emptystring;
+extern	char*	anames[];
+EXTERN	Hist*	hist;
+EXTERN	Prog	zprog;
+EXTERN	Node*	curfn;
+EXTERN	Node*	newproc;
+EXTERN	Node*	deferproc;
+EXTERN	Node*	deferreturn;
+EXTERN	Node*	panicindex;
+EXTERN	Node*	panicslice;
+EXTERN	Node*	throwreturn;
+EXTERN	long	unmappedzero;
+EXTERN	int	maxstksize;
+
+/*
+ * gen.c
+ */
+void	compile(Node*);
+void	proglist(void);
+void	gen(Node*);
+Node*	lookdot(Node*, Node*, int);
+void	cgen_as(Node*, Node*);
+void	cgen_callmeth(Node*, int);
+void	cgen_callinter(Node*, Node*, int);
+void	cgen_proc(Node*, int);
+void	cgen_callret(Node*, Node*);
+void	cgen_dcl(Node*);
+int	cgen_inline(Node*, Node*);
+int	needconvert(Type*, Type*);
+void	genconv(Type*, Type*);
+void	allocparams(void);
+void	checklabels();
+void	ginscall(Node*, int);
+
+/*
+ * cgen
+ */
+void	agen(Node*, Node*);
+Prog* cgenindex(Node *, Node *);
+void	igen(Node*, Node*, Node*);
+void agenr(Node *n, Node *a, Node *res);
+vlong	fieldoffset(Type*, Node*);
+void	bgen(Node*, int, Prog*);
+void	sgen(Node*, Node*, int32);
+void	gmove(Node*, Node*);
+Prog*	gins(int, Node*, Node*);
+int	samaddr(Node*, Node*);
+void	raddr(Node *n, Prog *p);
+Prog*	gcmp(int, Node*, Node*);
+Prog*	gshift(int as, Node *lhs, int32 stype, int32 sval, Node *rhs);
+Prog *	gregshift(int as, Node *lhs, int32 stype, Node *reg, Node *rhs);
+void	naddr(Node*, Addr*, int);
+void	cgen_aret(Node*, Node*);
+void	cgen_shift(int, Node*, Node*, Node*);
+
+/*
+ * cgen64.c
+ */
+void	cmp64(Node*, Node*, int, Prog*);
+void	cgen64(Node*, Node*);
+
+/*
+ * gsubr.c
+ */
+void	clearp(Prog*);
+void	proglist(void);
+Prog*	gbranch(int, Type*);
+Prog*	prog(int);
+void	gaddoffset(Node*);
+void	gconv(int, int);
+int	conv2pt(Type*);
+vlong	convvtox(vlong, int);
+void	fnparam(Type*, int, int);
+Prog*	gop(int, Node*, Node*, Node*);
+void	setconst(Addr*, vlong);
+void	setaddr(Addr*, Node*);
+int	optoas(int, Type*);
+void	ginit(void);
+void	gclean(void);
+void	regalloc(Node*, Type*, Node*);
+void	regfree(Node*);
+Node*	nodarg(Type*, int);
+void	nodreg(Node*, Type*, int);
+void	nodindreg(Node*, Type*, int);
+void	buildtxt(void);
+Plist*	newplist(void);
+int	isfat(Type*);
+int	dotaddable(Node*, Node*);
+void	sudoclean(void);
+int	sudoaddable(int, Node*, Addr*, int*);
+void	afunclit(Addr*);
+void	datagostring(Strlit*, Addr*);
+void	split64(Node*, Node*, Node*);
+void	splitclean(void);
+Node*	ncon(uint32 i);
+
+/*
+ * obj.c
+ */
+void	datastring(char*, int, Addr*);
+
+/*
+ * list.c
+ */
+int	Aconv(Fmt*);
+int	Cconv(Fmt*);
+int	Dconv(Fmt*);
+int	Mconv(Fmt*);
+int	Pconv(Fmt*);
+int	Rconv(Fmt*);
+int	Yconv(Fmt*);
+void	listinit(void);
+
+void	zaddr(Biobuf*, Addr*, int);
diff --git a/src/cmd/5g/ggen.c b/src/cmd/5g/ggen.c
new file mode 100644
index 000000000..3f5f47e7b
--- /dev/null
+++ b/src/cmd/5g/ggen.c
@@ -0,0 +1,1030 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#undef	EXTERN
+#define	EXTERN
+#include "gg.h"
+#include "opt.h"
+
+void
+defframe(Prog *ptxt)
+{
+	// fill in argument size
+	ptxt->to.type = D_CONST2;
+	ptxt->reg = 0; // flags
+	ptxt->to.offset2 = rnd(curfn->type->argwid, widthptr);
+
+	// fill in final stack size
+	if(stksize > maxstksize)
+		maxstksize = stksize;
+	ptxt->to.offset = rnd(maxstksize+maxarg, widthptr);
+	maxstksize = 0;
+}
+
+// Sweep the prog list to mark any used nodes.
+void
+markautoused(Prog* p)
+{
+	for (; p; p = p->link) {
+		if (p->from.name == D_AUTO && p->from.node)
+			p->from.node->used++;
+
+		if (p->to.name == D_AUTO && p->to.node)
+			p->to.node->used++;
+	}
+}
+
+// Fixup instructions after compactframe has moved all autos around.
+void
+fixautoused(Prog* p)
+{
+	for (; p; p = p->link) {
+		if (p->from.name == D_AUTO && p->from.node)
+			p->from.offset += p->from.node->stkdelta;
+
+		if (p->to.name == D_AUTO && p->to.node)
+			p->to.offset += p->to.node->stkdelta;
+	}
+}
+
+/*
+ * generate:
+ *	call f
+ *	proc=0	normal call
+ *	proc=1	goroutine run in new proc
+ *	proc=2	defer call save away stack
+ */
+void
+ginscall(Node *f, int proc)
+{
+	Prog *p;
+	Node n1, r, con;
+
+	switch(proc) {
+	default:
+		fatal("ginscall: bad proc %d", proc);
+		break;
+
+	case 0:	// normal call
+		p = gins(ABL, N, f);
+		afunclit(&p->to);
+		break;
+
+	case 1:	// call in new proc (go)
+	case 2:	// deferred call (defer)
+		regalloc(&r, types[tptr], N);
+		p = gins(AMOVW, N, &r);
+		p->from.type = D_OREG;
+		p->from.reg = REGSP;
+		
+		p = gins(AMOVW, &r, N);
+		p->to.type = D_OREG;
+		p->to.reg = REGSP;
+		p->to.offset = -12;
+		p->scond |= C_WBIT;
+
+		memset(&n1, 0, sizeof n1);
+		n1.op = OADDR;
+		n1.left = f;
+		gins(AMOVW, &n1, &r);
+
+		p = gins(AMOVW, &r, N);
+		p->to.type = D_OREG;
+		p->to.reg = REGSP;
+		p->to.offset = 8;
+
+		nodconst(&con, types[TINT32], argsize(f->type));
+		gins(AMOVW, &con, &r);
+		p = gins(AMOVW, &r, N);
+		p->to.type = D_OREG;
+		p->to.reg = REGSP;
+		p->to.offset = 4;
+		regfree(&r);
+
+		if(proc == 1)
+			ginscall(newproc, 0);
+		else
+			ginscall(deferproc, 0);
+
+		nodreg(&r, types[tptr], 1);
+		p = gins(AMOVW, N, N);
+		p->from.type = D_CONST;
+		p->from.reg = REGSP;
+		p->from.offset = 12;
+		p->to.reg = REGSP;
+		p->to.type = D_REG;
+
+		if(proc == 2) {
+			nodconst(&con, types[TINT32], 0);
+			p = gins(ACMP, &con, N);
+			p->reg = 0;
+			patch(gbranch(ABNE, T), retpc);
+		}
+		break;
+	}
+}
+
+/*
+ * n is call to interface method.
+ * generate res = n.
+ */
+void
+cgen_callinter(Node *n, Node *res, int proc)
+{
+	int r;
+	Node *i, *f;
+	Node tmpi, nodo, nodr, nodsp;
+
+	i = n->left;
+	if(i->op != ODOTINTER)
+		fatal("cgen_callinter: not ODOTINTER %O", i->op);
+
+	f = i->right;		// field
+	if(f->op != ONAME)
+		fatal("cgen_callinter: not ONAME %O", f->op);
+
+	i = i->left;		// interface
+
+	// Release res register during genlist and cgen,
+	// which might have their own function calls.
+	r = -1;
+	if(res != N && (res->op == OREGISTER || res->op == OINDREG)) {
+		r = res->val.u.reg;
+		reg[r]--;
+	}
+
+	if(!i->addable) {
+		tempname(&tmpi, i->type);
+		cgen(i, &tmpi);
+		i = &tmpi;
+	}
+
+	genlist(n->list);			// args
+	if(r >= 0)
+		reg[r]++;
+
+	regalloc(&nodr, types[tptr], res);
+	regalloc(&nodo, types[tptr], &nodr);
+	nodo.op = OINDREG;
+
+	agen(i, &nodr);		// REG = &inter
+
+	nodindreg(&nodsp, types[tptr], REGSP);
+	nodsp.xoffset = 4;
+	nodo.xoffset += widthptr;
+	cgen(&nodo, &nodsp);	// 4(SP) = 4(REG) -- i.data
+
+	nodo.xoffset -= widthptr;
+	cgen(&nodo, &nodr);	// REG = 0(REG) -- i.tab
+
+	nodo.xoffset = n->left->xoffset + 3*widthptr + 8;
+	cgen(&nodo, &nodr);	// REG = 20+offset(REG) -- i.tab->fun[f]
+
+	// BOTCH nodr.type = fntype;
+	nodr.type = n->left->type;
+	ginscall(&nodr, proc);
+
+	regfree(&nodr);
+	regfree(&nodo);
+
+	setmaxarg(n->left->type);
+}
+
+/*
+ * generate function call;
+ *	proc=0	normal call
+ *	proc=1	goroutine run in new proc
+ *	proc=2	defer call save away stack
+ */
+void
+cgen_call(Node *n, int proc)
+{
+	Type *t;
+	Node nod, afun;
+
+	if(n == N)
+		return;
+
+	if(n->left->ullman >= UINF) {
+		// if name involves a fn call
+		// precompute the address of the fn
+		tempname(&afun, types[tptr]);
+		cgen(n->left, &afun);
+	}
+
+	genlist(n->list);		// assign the args
+	t = n->left->type;
+
+	setmaxarg(t);
+
+	// call tempname pointer
+	if(n->left->ullman >= UINF) {
+		regalloc(&nod, types[tptr], N);
+		cgen_as(&nod, &afun);
+		nod.type = t;
+		ginscall(&nod, proc);
+		regfree(&nod);
+		goto ret;
+	}
+
+	// call pointer
+	if(n->left->op != ONAME || n->left->class != PFUNC) {
+		regalloc(&nod, types[tptr], N);
+		cgen_as(&nod, n->left);
+		nod.type = t;
+		ginscall(&nod, proc);
+		regfree(&nod);
+		goto ret;
+	}
+
+	// call direct
+	n->left->method = 1;
+	ginscall(n->left, proc);
+
+
+ret:
+	;
+}
+
+/*
+ * call to n has already been generated.
+ * generate:
+ *	res = return value from call.
+ */
+void
+cgen_callret(Node *n, Node *res)
+{
+	Node nod;
+	Type *fp, *t;
+	Iter flist;
+
+	t = n->left->type;
+	if(t->etype == TPTR32 || t->etype == TPTR64)
+		t = t->type;
+
+	fp = structfirst(&flist, getoutarg(t));
+	if(fp == T)
+		fatal("cgen_callret: nil");
+
+	memset(&nod, 0, sizeof(nod));
+	nod.op = OINDREG;
+	nod.val.u.reg = REGSP;
+	nod.addable = 1;
+
+	nod.xoffset = fp->width + 4; // +4: saved lr at 0(SP)
+	nod.type = fp->type;
+	cgen_as(res, &nod);
+}
+
+/*
+ * call to n has already been generated.
+ * generate:
+ *	res = &return value from call.
+ */
+void
+cgen_aret(Node *n, Node *res)
+{
+	Node nod1, nod2;
+	Type *fp, *t;
+	Iter flist;
+
+	t = n->left->type;
+	if(isptr[t->etype])
+		t = t->type;
+
+	fp = structfirst(&flist, getoutarg(t));
+	if(fp == T)
+		fatal("cgen_aret: nil");
+
+	memset(&nod1, 0, sizeof(nod1));
+	nod1.op = OINDREG;
+	nod1.val.u.reg = REGSP;
+	nod1.addable = 1;
+
+	nod1.xoffset = fp->width + 4; // +4: saved lr at 0(SP)
+	nod1.type = fp->type;
+
+	if(res->op != OREGISTER) {
+		regalloc(&nod2, types[tptr], res);
+		agen(&nod1, &nod2);
+		gins(AMOVW, &nod2, res);
+		regfree(&nod2);
+	} else
+		agen(&nod1, res);
+}
+
+/*
+ * generate return.
+ * n->left is assignments to return values.
+ */
+void
+cgen_ret(Node *n)
+{
+	genlist(n->list);		// copy out args
+	if(hasdefer || curfn->exit)
+		gjmp(retpc);
+	else
+		gins(ARET, N, N);
+}
+
+/*
+ * generate += *= etc.
+ */
+void
+cgen_asop(Node *n)
+{
+	Node n1, n2, n3, n4;
+	Node *nl, *nr;
+	Prog *p1;
+	Addr addr;
+	int a, w;
+
+	nl = n->left;
+	nr = n->right;
+
+	if(nr->ullman >= UINF && nl->ullman >= UINF) {
+		tempname(&n1, nr->type);
+		cgen(nr, &n1);
+		n2 = *n;
+		n2.right = &n1;
+		cgen_asop(&n2);
+		goto ret;
+	}
+
+	if(!isint[nl->type->etype])
+		goto hard;
+	if(!isint[nr->type->etype])
+		goto hard;
+	if(is64(nl->type) || is64(nr->type))
+		goto hard64;
+
+	switch(n->etype) {
+	case OADD:
+	case OSUB:
+	case OXOR:
+	case OAND:
+	case OOR:
+		a = optoas(n->etype, nl->type);
+		if(nl->addable) {
+			regalloc(&n3, nr->type, N);
+			cgen(nr, &n3);
+			regalloc(&n2, nl->type, N);
+			cgen(nl, &n2);
+			gins(a, &n3, &n2);
+			cgen(&n2, nl);
+			regfree(&n2);
+			regfree(&n3);
+			goto ret;
+		}
+		if(nr->ullman < UINF)
+		if(sudoaddable(a, nl, &addr, &w)) {
+			w = optoas(OAS, nl->type);
+			regalloc(&n2, nl->type, N);
+			p1 = gins(w, N, &n2);
+			p1->from = addr;
+			regalloc(&n3, nr->type, N);
+			cgen(nr, &n3);
+			gins(a, &n3, &n2);
+			p1 = gins(w, &n2, N);
+			p1->to = addr;
+			regfree(&n2);
+			regfree(&n3);
+			sudoclean();
+			goto ret;
+		}
+	}
+
+hard:
+	n2.op = 0;
+	n1.op = 0;
+	if(nr->ullman >= nl->ullman || nl->addable) {
+		regalloc(&n2, nr->type, N);
+		cgen(nr, &n2);
+		nr = &n2;
+	} else {
+		tempname(&n2, nr->type);
+		cgen(nr, &n2);
+		nr = &n2;
+	}
+	if(!nl->addable) {
+		igen(nl, &n1, N);
+		nl = &n1;
+	}
+
+	n3 = *n;
+	n3.left = nl;
+	n3.right = nr;
+	n3.op = n->etype;
+
+	regalloc(&n4, nl->type, N);
+	cgen(&n3, &n4);
+	gmove(&n4, nl);
+
+	if(n1.op)
+		regfree(&n1);
+	if(n2.op == OREGISTER)
+		regfree(&n2);
+	regfree(&n4);
+	goto ret;
+
+hard64:
+	if(nr->ullman > nl->ullman) {
+		tempname(&n2, nr->type);
+		cgen(nr, &n2);
+		igen(nl, &n1, N);
+	} else {
+		igen(nl, &n1, N);
+		tempname(&n2, nr->type);
+		cgen(nr, &n2);
+	}
+
+	n3 = *n;
+	n3.left = &n1;
+	n3.right = &n2;
+	n3.op = n->etype;
+
+	cgen(&n3, &n1);
+
+ret:
+	;
+}
+
+int
+samereg(Node *a, Node *b)
+{
+	if(a->op != OREGISTER)
+		return 0;
+	if(b->op != OREGISTER)
+		return 0;
+	if(a->val.u.reg != b->val.u.reg)
+		return 0;
+	return 1;
+}
+
+/*
+ * generate shift according to op, one of:
+ *	res = nl << nr
+ *	res = nl >> nr
+ */
+void
+cgen_shift(int op, Node *nl, Node *nr, Node *res)
+{
+	Node n1, n2, n3, nt, t, lo, hi;
+	int w;
+	Prog *p1, *p2, *p3;
+	Type *tr;
+	uvlong sc;
+
+	if(nl->type->width > 4)
+		fatal("cgen_shift %T", nl->type);
+
+	w = nl->type->width * 8;
+
+	if(nr->op == OLITERAL) {
+		regalloc(&n1, nl->type, res);
+		cgen(nl, &n1);
+		sc = mpgetfix(nr->val.u.xval);
+		if(sc == 0) {
+			// nothing to do
+		} else if(sc >= nl->type->width*8) {
+			if(op == ORSH && issigned[nl->type->etype])
+				gshift(AMOVW, &n1, SHIFT_AR, w, &n1);
+			else
+				gins(AEOR, &n1, &n1);
+		} else {
+			if(op == ORSH && issigned[nl->type->etype])
+				gshift(AMOVW, &n1, SHIFT_AR, sc, &n1);
+			else if(op == ORSH)
+				gshift(AMOVW, &n1, SHIFT_LR, sc, &n1);
+			else // OLSH
+				gshift(AMOVW, &n1, SHIFT_LL, sc, &n1);
+		}
+		gmove(&n1, res);
+		regfree(&n1);
+		return;
+	}
+
+	tr = nr->type;
+	if(tr->width > 4) {
+		tempname(&nt, nr->type);
+		if(nl->ullman >= nr->ullman) {
+			regalloc(&n2, nl->type, res);
+			cgen(nl, &n2);
+			cgen(nr, &nt);
+			n1 = nt;
+		} else {
+			cgen(nr, &nt);
+			regalloc(&n2, nl->type, res);
+			cgen(nl, &n2);
+		}
+		split64(&nt, &lo, &hi);
+		regalloc(&n1, types[TUINT32], N);
+		regalloc(&n3, types[TUINT32], N);
+		gmove(&lo, &n1);
+		gmove(&hi, &n3);
+		gins(ATST, &n3, N);
+		nodconst(&t, types[TUINT32], w);
+		p1 = gins(AMOVW, &t, &n1);
+		p1->scond = C_SCOND_NE;
+		tr = types[TUINT32];
+		regfree(&n3);
+	} else {
+		if(nl->ullman >= nr->ullman) {
+			regalloc(&n2, nl->type, res);
+			cgen(nl, &n2);
+			regalloc(&n1, nr->type, N);
+			cgen(nr, &n1);
+		} else {
+			regalloc(&n1, nr->type, N);
+			cgen(nr, &n1);
+			regalloc(&n2, nl->type, res);
+			cgen(nl, &n2);
+		}
+	}
+
+	// test for shift being 0
+	p1 = gins(ATST, &n1, N);
+	p3 = gbranch(ABEQ, T);
+
+	// test and fix up large shifts
+	regalloc(&n3, tr, N);
+	nodconst(&t, types[TUINT32], w);
+	gmove(&t, &n3);
+	gcmp(ACMP, &n1, &n3);
+	if(op == ORSH) {
+		if(issigned[nl->type->etype]) {
+			p1 = gshift(AMOVW, &n2, SHIFT_AR, w-1, &n2);
+			p2 = gregshift(AMOVW, &n2, SHIFT_AR, &n1, &n2);
+		} else {
+			p1 = gins(AEOR, &n2, &n2);
+			p2 = gregshift(AMOVW, &n2, SHIFT_LR, &n1, &n2);
+		}
+		p1->scond = C_SCOND_HS;
+		p2->scond = C_SCOND_LO;
+	} else {
+		p1 = gins(AEOR, &n2, &n2);
+		p2 = gregshift(AMOVW, &n2, SHIFT_LL, &n1, &n2);
+		p1->scond = C_SCOND_HS;
+		p2->scond = C_SCOND_LO;
+	}
+	regfree(&n3);
+
+	patch(p3, pc);
+	gmove(&n2, res);
+
+	regfree(&n1);
+	regfree(&n2);
+}
+
+void
+clearfat(Node *nl)
+{
+	uint32 w, c, q;
+	Node dst, nc, nz, end;
+	Prog *p, *pl;
+
+	/* clear a fat object */
+	if(debug['g'])
+		dump("\nclearfat", nl);
+
+	w = nl->type->width;
+	c = w % 4;	// bytes
+	q = w / 4;	// quads
+
+	regalloc(&dst, types[tptr], N);
+	agen(nl, &dst);
+	nodconst(&nc, types[TUINT32], 0);
+	regalloc(&nz, types[TUINT32], 0);
+	cgen(&nc, &nz);
+
+	if(q >= 4) {
+		regalloc(&end, types[tptr], N);
+		p = gins(AMOVW, &dst, &end);
+		p->from.type = D_CONST;
+		p->from.offset = q*4;
+
+		p = gins(AMOVW, &nz, &dst);
+		p->to.type = D_OREG;
+		p->to.offset = 4;
+		p->scond |= C_PBIT;
+		pl = p;
+
+		p = gins(ACMP, &dst, N);
+		raddr(&end, p);
+		patch(gbranch(ABNE, T), pl);
+
+		regfree(&end);
+	} else
+	while(q > 0) {
+		p = gins(AMOVW, &nz, &dst);
+		p->to.type = D_OREG;
+		p->to.offset = 4;
+ 		p->scond |= C_PBIT;
+//print("1. %P\n", p);
+		q--;
+	}
+
+	while(c > 0) {
+		p = gins(AMOVBU, &nz, &dst);
+		p->to.type = D_OREG;
+		p->to.offset = 1;
+ 		p->scond |= C_PBIT;
+//print("2. %P\n", p);
+		c--;
+	}
+	regfree(&dst);
+	regfree(&nz);
+}
+
+static int
+regcmp(const void *va, const void *vb)
+{
+	Node *ra, *rb;
+
+	ra = (Node*)va;
+	rb = (Node*)vb;
+	return ra->local - rb->local;
+}
+
+static	Prog*	throwpc;
+
+// We're only going to bother inlining if we can
+// convert all the arguments to 32 bits safely.  Can we?
+static int
+fix64(NodeList *nn, int n)
+{
+	NodeList *l;
+	Node *r;
+	int i;
+	
+	l = nn;
+	for(i=0; i<n; i++) {
+		r = l->n->right;
+		if(is64(r->type) && !smallintconst(r)) {
+			if(r->op == OCONV)
+				r = r->left;
+			if(is64(r->type))
+				return 0;
+		}
+		l = l->next;
+	}
+	return 1;
+}
+
+void
+getargs(NodeList *nn, Node *reg, int n)
+{
+	NodeList *l;
+	int i;
+
+	throwpc = nil;
+
+	l = nn;
+	for(i=0; i<n; i++) {
+		if(!smallintconst(l->n->right) && !isslice(l->n->right->type)) {
+			regalloc(reg+i, l->n->right->type, N);
+			cgen(l->n->right, reg+i);
+		} else
+			reg[i] = *l->n->right;
+		if(reg[i].local != 0)
+			yyerror("local used");
+		reg[i].local = l->n->left->xoffset;
+		l = l->next;
+	}
+	qsort((void*)reg, n, sizeof(*reg), regcmp);
+	for(i=0; i<n; i++)
+		reg[i].local = 0;
+}
+
+void
+cmpandthrow(Node *nl, Node *nr)
+{
+	vlong cl;
+	Prog *p1;
+	int op;
+	Node *c, n1, n2;
+
+	op = OLE;
+	if(smallintconst(nl)) {
+		cl = mpgetfix(nl->val.u.xval);
+		if(cl == 0)
+			return;
+		if(smallintconst(nr))
+			return;
+
+		// put the constant on the right
+		op = brrev(op);
+		c = nl;
+		nl = nr;
+		nr = c;
+	}
+
+	n1.op = OXXX;
+	if(nr->op != OREGISTER) {
+		regalloc(&n1, types[TUINT32], N);
+		gmove(nr, &n1);
+		nr = &n1;
+	}
+	n2.op = OXXX;
+	if(nl->op != OREGISTER) {
+		regalloc(&n2, types[TUINT32], N);
+		gmove(nl, &n2);
+		nl = &n2;
+	}
+	gcmp(optoas(OCMP, types[TUINT32]), nl, nr);
+	if(nr == &n1)
+		regfree(&n1);
+	if(nl == &n2)
+		regfree(&n2);
+	if(throwpc == nil) {
+		p1 = gbranch(optoas(op, types[TUINT32]), T);
+		throwpc = pc;
+		ginscall(panicslice, 0);
+		patch(p1, pc);
+	} else {
+		op = brcom(op);
+		p1 = gbranch(optoas(op, types[TUINT32]), T);
+		patch(p1, throwpc);
+	}
+}
+
+int
+sleasy(Node *n)
+{
+	if(n->op != ONAME)
+		return 0;
+	if(!n->addable)
+		return 0;
+	return 1;
+}
+
+// generate inline code for
+//	slicearray
+//	sliceslice
+//	arraytoslice
+int
+cgen_inline(Node *n, Node *res)
+{
+	Node nodes[5];
+	Node n1, n2, n3, nres, ntemp;
+	vlong v;
+	int i, narg;
+
+	if(n->op != OCALLFUNC)
+		goto no;
+	if(!n->left->addable)
+		goto no;
+	if(n->left->sym == S)
+		goto no;
+	if(n->left->sym->pkg != runtimepkg)
+		goto no;
+	if(strcmp(n->left->sym->name, "slicearray") == 0)
+		goto slicearray;
+	if(strcmp(n->left->sym->name, "sliceslice") == 0) {
+		narg = 4;
+		goto sliceslice;
+	}
+	if(strcmp(n->left->sym->name, "sliceslice1") == 0) {
+		narg = 3;
+		goto sliceslice;
+	}
+	goto no;
+
+slicearray:
+	if(!sleasy(res))
+		goto no;
+	if(!fix64(n->list, 5))
+		goto no;
+	getargs(n->list, nodes, 5);
+
+	// if(hb[3] > nel[1]) goto throw
+	cmpandthrow(&nodes[3], &nodes[1]);
+
+	// if(lb[2] > hb[3]) goto throw
+	cmpandthrow(&nodes[2], &nodes[3]);
+
+	// len = hb[3] - lb[2] (destroys hb)
+	n2 = *res;
+	n2.type = types[TUINT32];
+	n2.xoffset += Array_nel;
+
+	if(smallintconst(&nodes[3]) && smallintconst(&nodes[2])) {
+		v = mpgetfix(nodes[3].val.u.xval) -
+			mpgetfix(nodes[2].val.u.xval);
+		nodconst(&n1, types[TUINT32], v);
+		gmove(&n1, &n2);
+	} else {
+		regalloc(&n1, types[TUINT32], &nodes[3]);
+		gmove(&nodes[3], &n1);
+		if(!smallintconst(&nodes[2]) || mpgetfix(nodes[2].val.u.xval) != 0)
+			gins(optoas(OSUB, types[TUINT32]), &nodes[2], &n1);
+		gmove(&n1, &n2);
+		regfree(&n1);
+	}
+
+	// cap = nel[1] - lb[2] (destroys nel)
+	n2 = *res;
+	n2.type = types[TUINT32];
+	n2.xoffset += Array_cap;
+
+	if(smallintconst(&nodes[1]) && smallintconst(&nodes[2])) {
+		v = mpgetfix(nodes[1].val.u.xval) -
+			mpgetfix(nodes[2].val.u.xval);
+		nodconst(&n1, types[TUINT32], v);
+		gmove(&n1, &n2);
+	} else {
+		regalloc(&n1, types[TUINT32], &nodes[1]);
+		gmove(&nodes[1], &n1);
+		if(!smallintconst(&nodes[2]) || mpgetfix(nodes[2].val.u.xval) != 0)
+			gins(optoas(OSUB, types[TUINT32]), &nodes[2], &n1);
+		gmove(&n1, &n2);
+		regfree(&n1);
+	}
+
+	// if slice could be too big, dereference to
+	// catch nil array pointer.
+	if(nodes[0].op == OREGISTER && nodes[0].type->type->width >= unmappedzero) {
+		n2 = nodes[0];
+		n2.xoffset = 0;
+		n2.op = OINDREG;
+		n2.type = types[TUINT8];
+		regalloc(&n1, types[TUINT32], N);
+		gins(AMOVB, &n2, &n1);
+		regfree(&n1);
+	}
+
+	// ary = old[0] + (lb[2] * width[4]) (destroys old)
+	n2 = *res;
+	n2.type = types[tptr];
+	n2.xoffset += Array_array;
+
+	if(smallintconst(&nodes[2]) && smallintconst(&nodes[4])) {
+		v = mpgetfix(nodes[2].val.u.xval) *
+			mpgetfix(nodes[4].val.u.xval);
+		if(v != 0) {
+			nodconst(&n1, types[tptr], v);
+			gins(optoas(OADD, types[tptr]), &n1, &nodes[0]);
+		}
+	} else {
+		regalloc(&n1, types[tptr], &nodes[2]);
+		gmove(&nodes[2], &n1);
+		if(!smallintconst(&nodes[4]) || mpgetfix(nodes[4].val.u.xval) != 1) {
+			regalloc(&n3, types[tptr], N);
+			gmove(&nodes[4], &n3);
+			gins(optoas(OMUL, types[tptr]), &n3, &n1);
+			regfree(&n3);
+		}
+		gins(optoas(OADD, types[tptr]), &n1, &nodes[0]);
+		regfree(&n1);
+	}
+	gmove(&nodes[0], &n2);
+
+	for(i=0; i<5; i++) {
+		if(nodes[i].op == OREGISTER)
+			regfree(&nodes[i]);
+	}
+	return 1;
+
+sliceslice:
+	if(!fix64(n->list, narg))
+		goto no;
+	ntemp.op = OXXX;
+	if(!sleasy(n->list->n->right)) {
+		Node *n0;
+		
+		n0 = n->list->n->right;
+		tempname(&ntemp, res->type);
+		cgen(n0, &ntemp);
+		n->list->n->right = &ntemp;
+		getargs(n->list, nodes, narg);
+		n->list->n->right = n0;
+	} else
+		getargs(n->list, nodes, narg);
+
+	nres = *res;		// result
+	if(!sleasy(res)) {
+		if(ntemp.op == OXXX)
+			tempname(&ntemp, res->type);
+		nres = ntemp;
+	}
+
+	if(narg == 3) {	// old[lb:]
+		// move width to where it would be for old[lb:hb]
+		nodes[3] = nodes[2];
+		nodes[2].op = OXXX;
+		
+		// if(lb[1] > old.nel[0]) goto throw;
+		n2 = nodes[0];
+		n2.xoffset += Array_nel;
+		n2.type = types[TUINT32];
+		cmpandthrow(&nodes[1], &n2);
+
+		// ret.nel = old.nel[0]-lb[1];
+		n2 = nodes[0];
+		n2.type = types[TUINT32];
+		n2.xoffset += Array_nel;
+	
+		regalloc(&n1, types[TUINT32], N);
+		gmove(&n2, &n1);
+		if(!smallintconst(&nodes[1]) || mpgetfix(nodes[1].val.u.xval) != 0)
+			gins(optoas(OSUB, types[TUINT32]), &nodes[1], &n1);
+	
+		n2 = nres;
+		n2.type = types[TUINT32];
+		n2.xoffset += Array_nel;
+		gmove(&n1, &n2);
+		regfree(&n1);
+	} else {	// old[lb:hb]
+		// if(hb[2] > old.cap[0]) goto throw;
+		n2 = nodes[0];
+		n2.xoffset += Array_cap;
+		n2.type = types[TUINT32];
+		cmpandthrow(&nodes[2], &n2);
+
+		// if(lb[1] > hb[2]) goto throw;
+		cmpandthrow(&nodes[1], &nodes[2]);
+
+		// ret.len = hb[2]-lb[1]; (destroys hb[2])
+		n2 = nres;
+		n2.type = types[TUINT32];
+		n2.xoffset += Array_nel;
+	
+		if(smallintconst(&nodes[2]) && smallintconst(&nodes[1])) {
+			v = mpgetfix(nodes[2].val.u.xval) -
+				mpgetfix(nodes[1].val.u.xval);
+			nodconst(&n1, types[TUINT32], v);
+			gmove(&n1, &n2);
+		} else {
+			regalloc(&n1, types[TUINT32], &nodes[2]);
+			gmove(&nodes[2], &n1);
+			if(!smallintconst(&nodes[1]) || mpgetfix(nodes[1].val.u.xval) != 0)
+				gins(optoas(OSUB, types[TUINT32]), &nodes[1], &n1);
+			gmove(&n1, &n2);
+			regfree(&n1);
+		}
+	}
+
+	// ret.cap = old.cap[0]-lb[1]; (uses hb[2])
+	n2 = nodes[0];
+	n2.type = types[TUINT32];
+	n2.xoffset += Array_cap;
+
+	regalloc(&n1, types[TUINT32], &nodes[2]);
+	gmove(&n2, &n1);
+	if(!smallintconst(&nodes[1]) || mpgetfix(nodes[1].val.u.xval) != 0)
+		gins(optoas(OSUB, types[TUINT32]), &nodes[1], &n1);
+
+	n2 = nres;
+	n2.type = types[TUINT32];
+	n2.xoffset += Array_cap;
+	gmove(&n1, &n2);
+	regfree(&n1);
+
+	// ret.array = old.array[0]+lb[1]*width[3]; (uses lb[1])
+	n2 = nodes[0];
+	n2.type = types[tptr];
+	n2.xoffset += Array_array;
+	regalloc(&n3, types[tptr], N);
+	gmove(&n2, &n3);
+
+	regalloc(&n1, types[tptr], &nodes[1]);
+	if(smallintconst(&nodes[1]) && smallintconst(&nodes[3])) {
+		gmove(&n2, &n1);
+		v = mpgetfix(nodes[1].val.u.xval) *
+			mpgetfix(nodes[3].val.u.xval);
+		if(v != 0) {
+			nodconst(&n2, types[tptr], v);
+			gins(optoas(OADD, types[tptr]), &n3, &n1);
+		}
+	} else {
+		gmove(&nodes[1], &n1);
+		if(!smallintconst(&nodes[3]) || mpgetfix(nodes[3].val.u.xval) != 1) {
+			regalloc(&n2, types[tptr], N);
+			gmove(&nodes[3], &n2);
+			gins(optoas(OMUL, types[tptr]), &n2, &n1);
+			regfree(&n2);
+		}
+		gins(optoas(OADD, types[tptr]), &n3, &n1);
+	}
+	regfree(&n3);
+
+	n2 = nres;
+	n2.type = types[tptr];
+	n2.xoffset += Array_array;
+	gmove(&n1, &n2);
+	regfree(&n1);
+
+	for(i=0; i<4; i++) {
+		if(nodes[i].op == OREGISTER)
+			regfree(&nodes[i]);
+	}
+
+	if(!sleasy(res)) {
+		cgen(&nres, res);
+	}
+	return 1;
+
+no:
+	return 0;
+}
diff --git a/src/cmd/5g/gobj.c b/src/cmd/5g/gobj.c
new file mode 100644
index 000000000..27c8be67d
--- /dev/null
+++ b/src/cmd/5g/gobj.c
@@ -0,0 +1,623 @@
+// Derived from Inferno utils/5c/swt.c
+// http://code.google.com/p/inferno-os/source/browse/utils/5c/swt.c
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include "gg.h"
+
+void
+zname(Biobuf *b, Sym *s, int t)
+{
+	Bputc(b, ANAME);	/* as */
+	Bputc(b, t);		/* type */
+	Bputc(b, s->sym);	/* sym */
+
+	Bputname(b, s);
+}
+
+void
+zfile(Biobuf *b, char *p, int n)
+{
+	Bputc(b, ANAME);
+	Bputc(b, D_FILE);
+	Bputc(b, 1);
+	Bputc(b, '<');
+	Bwrite(b, p, n);
+	Bputc(b, 0);
+}
+
+void
+zhist(Biobuf *b, int line, vlong offset)
+{
+	Addr a;
+
+	Bputc(b, AHISTORY);
+	Bputc(b, C_SCOND_NONE);
+	Bputc(b, NREG);
+	Bputc(b, line);
+	Bputc(b, line>>8);
+	Bputc(b, line>>16);
+	Bputc(b, line>>24);
+	zaddr(b, &zprog.from, 0);
+	a = zprog.to;
+	if(offset != 0) {
+		a.offset = offset;
+		a.type = D_CONST;
+	}
+	zaddr(b, &a, 0);
+}
+
+void
+zaddr(Biobuf *b, Addr *a, int s)
+{
+	int32 l;
+	uint64 e;
+	int i;
+	char *n;
+
+	switch(a->type) {
+	case D_STATIC:
+	case D_AUTO:
+	case D_EXTERN:
+	case D_PARAM:
+		// TODO(kaib): remove once everything seems to work
+		fatal("We should no longer generate these as types");
+
+	default:
+		Bputc(b, a->type);
+		Bputc(b, a->reg);
+		Bputc(b, s);
+		Bputc(b, a->name);
+	}
+
+	switch(a->type) {
+	default:
+		print("unknown type %d in zaddr\n", a->type);
+
+	case D_NONE:
+	case D_REG:
+	case D_FREG:
+	case D_PSR:
+		break;
+
+	case D_CONST2:
+		l = a->offset2;
+		Bputc(b, l);
+		Bputc(b, l>>8);
+		Bputc(b, l>>16);
+		Bputc(b, l>>24); // fall through
+	case D_OREG:
+	case D_CONST:
+	case D_SHIFT:
+	case D_STATIC:
+	case D_AUTO:
+	case D_EXTERN:
+	case D_PARAM:
+		l = a->offset;
+		Bputc(b, l);
+		Bputc(b, l>>8);
+		Bputc(b, l>>16);
+		Bputc(b, l>>24);
+		break;
+
+	case D_BRANCH:
+		if(a->branch == nil)
+			fatal("unpatched branch");
+		a->offset = a->branch->loc;
+		l = a->offset;
+		Bputc(b, l);
+		Bputc(b, l>>8);
+		Bputc(b, l>>16);
+		Bputc(b, l>>24);
+		break;
+
+	case D_SCONST:
+		n = a->sval;
+		for(i=0; i<NSNAME; i++) {
+			Bputc(b, *n);
+			n++;
+		}
+		break;
+
+	case D_REGREG:
+		Bputc(b, a->offset);
+		break;
+
+	case D_FCONST:
+		ieeedtod(&e, a->dval);
+		l = e;
+		Bputc(b, l);
+		Bputc(b, l>>8);
+		Bputc(b, l>>16);
+		Bputc(b, l>>24);
+		l = e >> 32;
+		Bputc(b, l);
+		Bputc(b, l>>8);
+		Bputc(b, l>>16);
+		Bputc(b, l>>24);
+		break;
+	}
+}
+
+void
+dumpfuncs(void)
+{
+	Plist *pl;
+	int sf, st, t, sym;
+	struct { Sym *sym; short type; } h[NSYM];
+	Sym *s;
+	Prog *p;
+
+	for(sym=0; sym<NSYM; sym++) {
+		h[sym].sym = S;
+		h[sym].type = 0;
+	}
+	sym = 1;
+
+	// fix up pc
+	pcloc = 0;
+	for(pl=plist; pl!=nil; pl=pl->link) {
+		if(isblank(pl->name))
+			continue;
+		for(p=pl->firstpc; p!=P; p=p->link) {
+			p->loc = pcloc;
+			if(p->as != ADATA && p->as != AGLOBL)
+				pcloc++;
+		}
+	}
+
+	// put out functions
+	for(pl=plist; pl!=nil; pl=pl->link) {
+		if(isblank(pl->name))
+			continue;
+
+		if(debug['S']) {
+			s = S;
+			if(pl->name != N)
+				s = pl->name->sym;
+			print("\n--- prog list \"%S\" ---\n", s);
+			for(p=pl->firstpc; p!=P; p=p->link)
+				print("%P\n", p);
+		}
+
+		for(p=pl->firstpc; p!=P; p=p->link) {
+		jackpot:
+			sf = 0;
+			s = p->from.sym;
+			while(s != S) {
+				sf = s->sym;
+				if(sf < 0 || sf >= NSYM)
+					sf = 0;
+				t = p->from.name;
+				if(t == D_ADDR)
+					t = p->from.name;
+				if(h[sf].type == t)
+				if(h[sf].sym == s)
+					break;
+				s->sym = sym;
+				zname(bout, s, t);
+				h[sym].sym = s;
+				h[sym].type = t;
+				sf = sym;
+				sym++;
+				if(sym >= NSYM)
+					sym = 1;
+				break;
+			}
+			st = 0;
+			s = p->to.sym;
+			while(s != S) {
+				st = s->sym;
+				if(st < 0 || st >= NSYM)
+					st = 0;
+				t = p->to.name;
+				if(t == D_ADDR)
+					t = p->to.name;
+				if(h[st].type == t)
+				if(h[st].sym == s)
+					break;
+				s->sym = sym;
+				zname(bout, s, t);
+				h[sym].sym = s;
+				h[sym].type = t;
+				st = sym;
+				sym++;
+				if(sym >= NSYM)
+					sym = 1;
+				if(st == sf)
+					goto jackpot;
+				break;
+			}
+			Bputc(bout, p->as);
+			Bputc(bout, p->scond);
+ 			Bputc(bout, p->reg);
+			Bputc(bout, p->lineno);
+			Bputc(bout, p->lineno>>8);
+			Bputc(bout, p->lineno>>16);
+			Bputc(bout, p->lineno>>24);
+			zaddr(bout, &p->from, sf);
+			zaddr(bout, &p->to, st);
+		}
+	}
+}
+
+/* deferred DATA output */
+static Prog *strdat;
+static Prog *estrdat;
+static int gflag;
+static Prog *savepc;
+
+void
+data(void)
+{
+	gflag = debug['g'];
+	debug['g'] = 0;
+
+	if(estrdat == nil) {
+		strdat = mal(sizeof(*pc));
+		clearp(strdat);
+		estrdat = strdat;
+	}
+	if(savepc)
+		fatal("data phase error");
+	savepc = pc;
+	pc = estrdat;
+}
+
+void
+text(void)
+{
+	if(!savepc)
+		fatal("text phase error");
+	debug['g'] = gflag;
+	estrdat = pc;
+	pc = savepc;
+	savepc = nil;
+}
+
+void
+dumpdata(void)
+{
+	Prog *p;
+
+	if(estrdat == nil)
+		return;
+	*pc = *strdat;
+	if(gflag)
+		for(p=pc; p!=estrdat; p=p->link)
+			print("%P\n", p);
+	pc = estrdat;
+}
+
+int
+dsname(Sym *sym, int off, char *t, int n)
+{
+	Prog *p;
+
+	p = gins(ADATA, N, N);
+	p->from.type = D_OREG;
+	p->from.name = D_EXTERN;
+	p->from.etype = TINT32;
+	p->from.offset = off;
+	p->from.reg = NREG;
+	p->from.sym = sym;
+	
+	p->reg = n;
+	
+	p->to.type = D_SCONST;
+	p->to.name = D_NONE;
+	p->to.reg = NREG;
+	p->to.offset = 0;
+	memmove(p->to.sval, t, n);
+	return off + n;
+}
+
+/*
+ * make a refer to the data s, s+len
+ * emitting DATA if needed.
+ */
+void
+datastring(char *s, int len, Addr *a)
+{
+	Sym *sym;
+	
+	sym = stringsym(s, len);
+	a->type = D_OREG;
+	a->name = D_EXTERN;
+	a->etype = TINT32;
+	a->offset = widthptr+4;  // skip header
+	a->reg = NREG;
+	a->sym = sym;
+}
+
+/*
+ * make a refer to the string sval,
+ * emitting DATA if needed.
+ */
+void
+datagostring(Strlit *sval, Addr *a)
+{
+	Sym *sym;
+	
+	sym = stringsym(sval->s, sval->len);
+	a->type = D_OREG;
+	a->name = D_EXTERN;
+	a->etype = TINT32;
+	a->offset = 0;  // header
+	a->reg = NREG;
+	a->sym = sym;
+}
+
+void
+gdata(Node *nam, Node *nr, int wid)
+{
+	Prog *p;
+	vlong v;
+
+	if(wid == 8 && is64(nr->type)) {
+		v = mpgetfix(nr->val.u.xval);
+		p = gins(ADATA, nam, nodintconst(v));
+		p->reg = 4;
+		p = gins(ADATA, nam, nodintconst(v>>32));
+		p->reg = 4;
+		p->from.offset += 4;
+		return;
+	}
+	p = gins(ADATA, nam, nr);
+	p->reg = wid;
+}
+
+void
+gdatacomplex(Node *nam, Mpcplx *cval)
+{
+	Prog *p;
+	int w;
+
+	w = cplxsubtype(nam->type->etype);
+	w = types[w]->width;
+
+	p = gins(ADATA, nam, N);
+	p->reg = w;
+	p->to.type = D_FCONST;
+	p->to.dval = mpgetflt(&cval->real);
+
+	p = gins(ADATA, nam, N);
+	p->reg = w;
+	p->from.offset += w;
+	p->to.type = D_FCONST;
+	p->to.dval = mpgetflt(&cval->imag);
+}
+
+void
+gdatastring(Node *nam, Strlit *sval)
+{
+	Prog *p;
+	Node nod1;
+
+	p = gins(ADATA, nam, N);
+	datastring(sval->s, sval->len, &p->to);
+	p->reg = types[tptr]->width;
+	p->to.type = D_CONST;
+	p->to.etype = TINT32;
+//print("%P\n", p);
+
+	nodconst(&nod1, types[TINT32], sval->len);
+	p = gins(ADATA, nam, &nod1);
+	p->reg = types[TINT32]->width;
+	p->from.offset += types[tptr]->width;
+}
+
+int
+dstringptr(Sym *s, int off, char *str)
+{
+	Prog *p;
+
+	off = rnd(off, widthptr);
+	p = gins(ADATA, N, N);
+	p->from.type = D_OREG;
+	p->from.name = D_EXTERN;
+	p->from.sym = s;
+	p->from.offset = off;
+	p->reg = widthptr;
+
+	datastring(str, strlen(str)+1, &p->to);
+	p->to.type = D_CONST;
+	p->to.etype = TINT32;
+	off += widthptr;
+
+	return off;
+}
+
+int
+dgostrlitptr(Sym *s, int off, Strlit *lit)
+{
+	Prog *p;
+
+	if(lit == nil)
+		return duintptr(s, off, 0);
+
+	off = rnd(off, widthptr);
+	p = gins(ADATA, N, N);
+	p->from.type = D_OREG;
+	p->from.name = D_EXTERN;
+	p->from.sym = s;
+	p->from.offset = off;
+	p->reg = widthptr;
+	datagostring(lit, &p->to);
+	p->to.type = D_CONST;
+	p->to.etype = TINT32;
+	off += widthptr;
+
+	return off;
+}
+
+int
+dgostringptr(Sym *s, int off, char *str)
+{
+	int n;
+	Strlit *lit;
+
+	if(str == nil)
+		return duintptr(s, off, 0);
+
+	n = strlen(str);
+	lit = mal(sizeof *lit + n);
+	strcpy(lit->s, str);
+	lit->len = n;
+	return dgostrlitptr(s, off, lit);
+}
+
+int
+duintxx(Sym *s, int off, uint64 v, int wid)
+{
+	Prog *p;
+
+	off = rnd(off, wid);
+
+	p = gins(ADATA, N, N);
+	p->from.type = D_OREG;
+	p->from.name = D_EXTERN;
+	p->from.sym = s;
+	p->from.offset = off;
+	p->reg = wid;
+	p->to.type = D_CONST;
+	p->to.name = D_NONE;
+	p->to.offset = v;
+	off += wid;
+
+	return off;
+}
+
+int
+dsymptr(Sym *s, int off, Sym *x, int xoff)
+{
+	Prog *p;
+
+	off = rnd(off, widthptr);
+
+	p = gins(ADATA, N, N);
+	p->from.type = D_OREG;
+	p->from.name = D_EXTERN;
+	p->from.sym = s;
+	p->from.offset = off;
+	p->reg = widthptr;
+	p->to.type = D_CONST;
+	p->to.name = D_EXTERN;
+	p->to.sym = x;
+	p->to.offset = xoff;
+	off += widthptr;
+
+	return off;
+}
+
+
+void
+genembedtramp(Type *rcvr, Type *method, Sym *newnam, int iface)
+{
+	// TODO(kaib): re-implement genembedtramp
+	genwrapper(rcvr, method, newnam, iface);
+/*
+	Sym *e;
+	int c, d, o;
+	Prog *p;
+	Type *f;
+
+	e = method->sym;
+	for(d=0; d<nelem(dotlist); d++) {
+		c = adddot1(e, rcvr, d, nil, 0);
+		if(c == 1)
+			goto out;
+	}
+	fatal("genembedtramp %T.%S", rcvr, method->sym);
+
+out:
+	newplist()->name = newname(newnam);
+
+	//TEXT	main·S_test2(SB),7,$0
+	p = pc;
+	gins(ATEXT, N, N);
+	p->from.type = D_OREG;
+	p->from.name = D_EXTERN;
+	p->from.sym = newnam;
+	p->to.type = D_CONST2;
+	p->reg = 7;
+	p->to.offset2 = 0;
+	p->to.reg = NREG;
+//print("1. %P\n", p);
+
+	o = 0;
+	for(c=d-1; c>=0; c--) {
+		f = dotlist[c].field;
+		o += f->width;
+		if(!isptr[f->type->etype])
+			continue;
+
+		//MOVW	o(R0), R0
+		p = pc;
+		gins(AMOVW, N, N);
+		p->from.type = D_OREG;
+		p->from.reg = REGARG;
+		p->from.offset = o;
+		p->to.type = D_REG;
+		p->to.reg = REGARG;
+//print("2. %P\n", p);
+		o = 0;
+	}
+	if(o != 0) {
+		//MOVW	$XX(R0), R0
+		p = pc;
+		gins(AMOVW, N, N);
+		p->from.type = D_CONST;
+		p->from.reg = REGARG;
+		p->from.offset = o;
+		p->to.type = D_REG;
+		p->to.reg = REGARG;
+//print("3. %P\n", p);
+	}
+
+	f = dotlist[0].field;
+	//B	main·*Sub_test2(SB)
+	if(isptr[f->type->etype])
+		f = f->type;
+	p = pc;
+	gins(AB, N, N);
+	p->to.type = D_OREG;
+	p->to.reg = NREG;
+	p->to.name = D_EXTERN;
+	p->to.sym = methodsym(method->sym, ptrto(f->type), 0);
+//print("4. %P\n", p);
+
+	pc->as = ARET;	// overwrite AEND
+*/
+}
+
+void
+nopout(Prog *p)
+{
+	p->as = ANOP;
+}
diff --git a/src/cmd/5g/gsubr.c b/src/cmd/5g/gsubr.c
new file mode 100644
index 000000000..ddaf52a88
--- /dev/null
+++ b/src/cmd/5g/gsubr.c
@@ -0,0 +1,2010 @@
+// Derived from Inferno utils/5c/txt.c
+// http://code.google.com/p/inferno-os/source/browse/utils/5c/txt.c
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include "gg.h"
+
+// TODO(kaib): Can make this bigger if we move
+// the text segment up higher in 5l for all GOOS.
+long unmappedzero = 4096;
+
+void
+clearp(Prog *p)
+{
+	p->as = AEND;
+	p->reg = NREG;
+	p->scond = C_SCOND_NONE;
+	p->from.type = D_NONE;
+	p->from.name = D_NONE;
+	p->from.reg = NREG;
+	p->to.type = D_NONE;
+	p->to.name = D_NONE;
+	p->to.reg = NREG;
+	p->loc = pcloc;
+	pcloc++;
+}
+
+/*
+ * generate and return proc with p->as = as,
+ * linked into program.  pc is next instruction.
+ */
+Prog*
+prog(int as)
+{
+	Prog *p;
+
+	p = pc;
+	pc = mal(sizeof(*pc));
+
+	clearp(pc);
+
+	if(lineno == 0) {
+		if(debug['K'])
+			warn("prog: line 0");
+	}
+
+	p->as = as;
+	p->lineno = lineno;
+	p->link = pc;
+	return p;
+}
+
+/*
+ * generate a branch.
+ * t is ignored.
+ */
+Prog*
+gbranch(int as, Type *t)
+{
+	Prog *p;
+
+	p = prog(as);
+	p->to.type = D_BRANCH;
+	p->to.branch = P;
+	return p;
+}
+
+/*
+ * patch previous branch to jump to to.
+ */
+void
+patch(Prog *p, Prog *to)
+{
+	if(p->to.type != D_BRANCH)
+		fatal("patch: not a branch");
+	p->to.branch = to;
+	p->to.offset = to->loc;
+}
+
+Prog*
+unpatch(Prog *p)
+{
+	Prog *q;
+
+	if(p->to.type != D_BRANCH)
+		fatal("unpatch: not a branch");
+	q = p->to.branch;
+	p->to.branch = P;
+	p->to.offset = 0;
+	return q;
+}
+
+/*
+ * start a new Prog list.
+ */
+Plist*
+newplist(void)
+{
+	Plist *pl;
+
+	pl = mal(sizeof(*pl));
+	if(plist == nil)
+		plist = pl;
+	else
+		plast->link = pl;
+	plast = pl;
+
+	pc = mal(sizeof(*pc));
+	clearp(pc);
+	pl->firstpc = pc;
+
+	return pl;
+}
+
+void
+clearstk(void)
+{
+	Plist *pl;
+	Prog *p, *p1, *p2, *p3;
+	Node dst, end, zero, con;
+
+	if(plast->firstpc->to.offset <= 0)
+		return;
+
+	// reestablish context for inserting code
+	// at beginning of function.
+	pl = plast;
+	p1 = pl->firstpc;
+	p2 = p1->link;
+	pc = mal(sizeof(*pc));
+	clearp(pc);
+	p1->link = pc;
+	
+	// zero stack frame
+
+	// MOVW $4(SP), R1
+	nodreg(&dst, types[tptr], 1);
+	p = gins(AMOVW, N, &dst);
+	p->from.type = D_CONST;
+	p->from.reg = REGSP;
+	p->from.offset = 4;
+
+	// MOVW $n(R1), R2
+	nodreg(&end, types[tptr], 2);
+	p = gins(AMOVW, N, &end);
+	p->from.type = D_CONST;
+	p->from.reg = 1;
+	p->from.offset = p1->to.offset;
+	
+	// MOVW $0, R3
+	nodreg(&zero, types[TUINT32], 3);
+	nodconst(&con, types[TUINT32], 0);
+	gmove(&con, &zero);
+
+	// L:
+	//	MOVW.P R3, 0(R1) +4
+	//	CMP R1, R2
+	//	BNE L
+	p = gins(AMOVW, &zero, &dst);
+	p->to.type = D_OREG;
+	p->to.offset = 4;
+	p->scond |= C_PBIT;
+	p3 = p;
+	p = gins(ACMP, &dst, N);
+	raddr(&end, p);
+	patch(gbranch(ABNE, T), p3);
+
+	// continue with original code.
+	gins(ANOP, N, N)->link = p2;
+	pc = P;
+}	
+
+void
+gused(Node *n)
+{
+	gins(ANOP, n, N);	// used
+}
+
+Prog*
+gjmp(Prog *to)
+{
+	Prog *p;
+
+	p = gbranch(AB, T);
+	if(to != P)
+		patch(p, to);
+	return p;
+}
+
+void
+ggloblnod(Node *nam, int32 width)
+{
+	Prog *p;
+
+	p = gins(AGLOBL, nam, N);
+	p->lineno = nam->lineno;
+	p->to.sym = S;
+	p->to.type = D_CONST;
+	p->to.offset = width;
+}
+
+void
+ggloblsym(Sym *s, int32 width, int dupok)
+{
+	Prog *p;
+
+	p = gins(AGLOBL, N, N);
+	p->from.type = D_OREG;
+	p->from.name = D_EXTERN;
+	p->from.sym = s;
+	p->to.type = D_CONST;
+	p->to.name = D_NONE;
+	p->to.offset = width;
+	if(dupok)
+		p->reg = DUPOK;
+}
+
+int
+isfat(Type *t)
+{
+	if(t != T)
+	switch(t->etype) {
+	case TSTRUCT:
+	case TARRAY:
+	case TSTRING:
+	case TINTER:	// maybe remove later
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * naddr of func generates code for address of func.
+ * if using opcode that can take address implicitly,
+ * call afunclit to fix up the argument.
+ * also fix up direct register references to be D_OREG.
+ */
+void
+afunclit(Addr *a)
+{
+	if(a->type == D_CONST && a->name == D_EXTERN || a->type == D_REG) {
+		a->type = D_OREG;
+	}
+}
+
+static	int	resvd[] =
+{
+	9,	// reserved for m
+	10,	// reserved for g
+};
+
+void
+ginit(void)
+{
+	int i;
+
+	for(i=0; i<nelem(reg); i++)
+		reg[i] = 0;
+	for(i=0; i<nelem(resvd); i++)
+		reg[resvd[i]]++;
+}
+
+void
+gclean(void)
+{
+	int i;
+
+	for(i=0; i<nelem(resvd); i++)
+		reg[resvd[i]]--;
+
+	for(i=0; i<nelem(reg); i++)
+		if(reg[i])
+			yyerror("reg %R left allocated\n", i);
+}
+
+int32
+anyregalloc(void)
+{
+	int i, j;
+
+	for(i=0; i<nelem(reg); i++) {
+		if(reg[i] == 0)
+			goto ok;
+		for(j=0; j<nelem(resvd); j++)
+			if(resvd[j] == i)
+				goto ok;
+		return 1;
+	ok:;
+	}
+	return 0;
+}
+
+/*
+ * allocate register of type t, leave in n.
+ * if o != N, o is desired fixed register.
+ * caller must regfree(n).
+ */
+void
+regalloc(Node *n, Type *t, Node *o)
+{
+	int i, et, fixfree, floatfree;
+
+	if(debug['r']) {
+		fixfree = 0;
+		for(i=REGALLOC_R0; i<=REGALLOC_RMAX; i++)
+			if(reg[i] == 0)
+				fixfree++;
+		floatfree = 0;
+		for(i=REGALLOC_F0; i<=REGALLOC_FMAX; i++)
+			if(reg[i] == 0)
+				floatfree++;
+		print("regalloc fix %d float %d\n", fixfree, floatfree);
+	}
+
+	if(t == T)
+		fatal("regalloc: t nil");
+	et = simtype[t->etype];
+	if(is64(t))
+		fatal("regalloc: 64 bit type %T");
+
+	switch(et) {
+	case TINT8:
+	case TUINT8:
+	case TINT16:
+	case TUINT16:
+	case TINT32:
+	case TUINT32:
+	case TPTR32:
+	case TBOOL:
+		if(o != N && o->op == OREGISTER) {
+			i = o->val.u.reg;
+			if(i >= REGALLOC_R0 && i <= REGALLOC_RMAX)
+				goto out;
+		}
+		for(i=REGALLOC_R0; i<=REGALLOC_RMAX; i++)
+			if(reg[i] == 0)
+				goto out;
+
+		yyerror("out of fixed registers");
+		goto err;
+
+	case TFLOAT32:
+	case TFLOAT64:
+		if(o != N && o->op == OREGISTER) {
+			i = o->val.u.reg;
+			if(i >= REGALLOC_F0 && i <= REGALLOC_FMAX)
+				goto out;
+		}
+		for(i=REGALLOC_F0; i<=REGALLOC_FMAX; i++)
+			if(reg[i] == 0)
+				goto out;
+		yyerror("out of floating point registers");
+		goto err;
+
+	case TCOMPLEX64:
+	case TCOMPLEX128:
+		tempname(n, t);
+		return;
+	}
+	yyerror("regalloc: unknown type %T", t);
+
+err:
+	nodreg(n, t, 0);
+	return;
+
+out:
+	reg[i]++;
+	nodreg(n, t, i);
+}
+
+void
+regfree(Node *n)
+{
+	int i, fixfree, floatfree;
+
+	if(debug['r']) {
+		fixfree = 0;
+		for(i=REGALLOC_R0; i<=REGALLOC_RMAX; i++)
+			if(reg[i] == 0)
+				fixfree++;
+		floatfree = 0;
+		for(i=REGALLOC_F0; i<=REGALLOC_FMAX; i++)
+			if(reg[i] == 0)
+				floatfree++;
+		print("regalloc fix %d float %d\n", fixfree, floatfree);
+	}
+
+	if(n->op == ONAME && iscomplex[n->type->etype])
+		return;
+	if(n->op != OREGISTER && n->op != OINDREG)
+		fatal("regfree: not a register");
+	i = n->val.u.reg;
+	if(i < 0 || i >= sizeof(reg))
+		fatal("regfree: reg out of range");
+	if(reg[i] <= 0)
+		fatal("regfree: reg not allocated");
+	reg[i]--;
+}
+
+/*
+ * initialize n to be register r of type t.
+ */
+void
+nodreg(Node *n, Type *t, int r)
+{
+	if(t == T)
+		fatal("nodreg: t nil");
+
+	memset(n, 0, sizeof(*n));
+	n->op = OREGISTER;
+	n->addable = 1;
+	ullmancalc(n);
+	n->val.u.reg = r;
+	n->type = t;
+}
+
+/*
+ * initialize n to be indirect of register r; n is type t.
+ */
+void
+nodindreg(Node *n, Type *t, int r)
+{
+	nodreg(n, t, r);
+	n->op = OINDREG;
+}
+
+Node*
+nodarg(Type *t, int fp)
+{
+	Node *n;
+	Type *first;
+	Iter savet;
+
+	// entire argument struct, not just one arg
+	if(t->etype == TSTRUCT && t->funarg) {
+		n = nod(ONAME, N, N);
+		n->sym = lookup(".args");
+		n->type = t;
+		first = structfirst(&savet, &t);
+		if(first == nil)
+			fatal("nodarg: bad struct");
+		if(first->width == BADWIDTH)
+			fatal("nodarg: offset not computed for %T", t);
+		n->xoffset = first->width;
+		n->addable = 1;
+		goto fp;
+	}
+
+	if(t->etype != TFIELD)
+		fatal("nodarg: not field %T", t);
+
+	n = nod(ONAME, N, N);
+	n->type = t->type;
+	n->sym = t->sym;
+	if(t->width == BADWIDTH)
+		fatal("nodarg: offset not computed for %T", t);
+	n->xoffset = t->width;
+	n->addable = 1;
+
+fp:
+	switch(fp) {
+	default:
+		fatal("nodarg %T %d", t, fp);
+
+	case 0:		// output arg for calling another function
+		n->op = OINDREG;
+		n->val.u.reg = REGSP;
+		n->xoffset += 4;
+		break;
+
+	case 1:		// input arg to current function
+		n->class = PPARAM;
+		break;
+	}
+	n->typecheck = 1;
+	return n;
+}
+
+/*
+ * return constant i node.
+ * overwritten by next call, but useful in calls to gins.
+ */
+Node*
+ncon(uint32 i)
+{
+	static Node n;
+
+	if(n.type == T)
+		nodconst(&n, types[TUINT32], 0);
+	mpmovecfix(n.val.u.xval, i);
+	return &n;
+}
+
+/*
+ * Is this node a memory operand?
+ */
+int
+ismem(Node *n)
+{
+	switch(n->op) {
+	case OINDREG:
+	case ONAME:
+	case OPARAM:
+		return 1;
+	}
+	return 0;
+}
+
+Node sclean[10];
+int nsclean;
+
+/*
+ * n is a 64-bit value.  fill in lo and hi to refer to its 32-bit halves.
+ */
+void
+split64(Node *n, Node *lo, Node *hi)
+{
+	Node n1;
+	int64 i;
+
+	if(!is64(n->type))
+		fatal("split64 %T", n->type);
+
+	sclean[nsclean].op = OEMPTY;
+	if(nsclean >= nelem(sclean))
+		fatal("split64 clean");
+	nsclean++;
+	switch(n->op) {
+	default:
+		if(!dotaddable(n, &n1)) {
+			igen(n, &n1, N);
+			sclean[nsclean-1] = n1;
+		}
+		n = &n1;
+		goto common;
+	case ONAME:
+		if(n->class == PPARAMREF) {
+			cgen(n->heapaddr, &n1);
+			sclean[nsclean-1] = n1;
+			// fall through.
+			n = &n1;
+		}
+		goto common;
+	case OINDREG:
+	common:
+		*lo = *n;
+		*hi = *n;
+		lo->type = types[TUINT32];
+		if(n->type->etype == TINT64)
+			hi->type = types[TINT32];
+		else
+			hi->type = types[TUINT32];
+		hi->xoffset += 4;
+		break;
+
+	case OLITERAL:
+		convconst(&n1, n->type, &n->val);
+		i = mpgetfix(n1.val.u.xval);
+		nodconst(lo, types[TUINT32], (uint32)i);
+		i >>= 32;
+		if(n->type->etype == TINT64)
+			nodconst(hi, types[TINT32], (int32)i);
+		else
+			nodconst(hi, types[TUINT32], (uint32)i);
+		break;
+	}
+}
+
+void
+splitclean(void)
+{
+	if(nsclean <= 0)
+		fatal("splitclean");
+	nsclean--;
+	if(sclean[nsclean].op != OEMPTY)
+		regfree(&sclean[nsclean]);
+}
+
+#define	CASE(a,b)	(((a)<<16)|((b)<<0))
+
+void
+gmove(Node *f, Node *t)
+{
+	int a, ft, tt, fa, ta;
+	Type *cvt;
+	Node r1, r2, flo, fhi, tlo, thi, con;
+	Prog *p1;
+
+	if(debug['M'])
+		print("gmove %N -> %N\n", f, t);
+
+	ft = simsimtype(f->type);
+	tt = simsimtype(t->type);
+	cvt = t->type;
+
+	if(iscomplex[ft] || iscomplex[tt]) {
+		complexmove(f, t);
+		return;
+	}
+
+	// cannot have two memory operands;
+	// except 64-bit, which always copies via registers anyway.
+	if(!is64(f->type) && !is64(t->type) && ismem(f) && ismem(t))
+		goto hard;
+
+	// convert constant to desired type
+	if(f->op == OLITERAL) {
+		switch(tt) {
+		default:
+			convconst(&con, t->type, &f->val);
+			break;
+
+		case TINT16:
+		case TINT8:
+			convconst(&con, types[TINT32], &f->val);
+			regalloc(&r1, con.type, t);
+			gins(AMOVW, &con, &r1);
+			gmove(&r1, t);
+			regfree(&r1);
+			return;
+
+		case TUINT16:
+		case TUINT8:
+			convconst(&con, types[TUINT32], &f->val);
+			regalloc(&r1, con.type, t);
+			gins(AMOVW, &con, &r1);
+			gmove(&r1, t);
+			regfree(&r1);
+			return;
+		}
+
+		f = &con;
+		ft = simsimtype(con.type);
+
+		// constants can't move directly to memory
+		if(ismem(t) && !is64(t->type)) goto hard;
+	}
+
+	// value -> value copy, only one memory operand.
+	// figure out the instruction to use.
+	// break out of switch for one-instruction gins.
+	// goto rdst for "destination must be register".
+	// goto hard for "convert to cvt type first".
+	// otherwise handle and return.
+
+	switch(CASE(ft, tt)) {
+	default:
+		goto fatal;
+
+	/*
+	 * integer copy and truncate
+	 */
+	case CASE(TINT8, TINT8):	// same size
+	case CASE(TUINT8, TINT8):
+	case CASE(TINT16, TINT8):	// truncate
+	case CASE(TUINT16, TINT8):
+	case CASE(TINT32, TINT8):
+	case CASE(TUINT32, TINT8):
+		a = AMOVB;
+		break;
+
+	case CASE(TINT8, TUINT8):
+	case CASE(TUINT8, TUINT8):
+	case CASE(TINT16, TUINT8):
+	case CASE(TUINT16, TUINT8):
+	case CASE(TINT32, TUINT8):
+	case CASE(TUINT32, TUINT8):
+		a = AMOVBU;
+		break;
+
+	case CASE(TINT64, TINT8):	// truncate low word
+	case CASE(TUINT64, TINT8):
+		a = AMOVB;
+		goto trunc64;
+
+	case CASE(TINT64, TUINT8):
+	case CASE(TUINT64, TUINT8):
+		a = AMOVBU;
+		goto trunc64;
+
+	case CASE(TINT16, TINT16):	// same size
+	case CASE(TUINT16, TINT16):
+	case CASE(TINT32, TINT16):	// truncate
+	case CASE(TUINT32, TINT16):
+		a = AMOVH;
+		break;
+
+	case CASE(TINT16, TUINT16):
+	case CASE(TUINT16, TUINT16):
+	case CASE(TINT32, TUINT16):
+	case CASE(TUINT32, TUINT16):
+		a = AMOVHU;
+		break;
+
+	case CASE(TINT64, TINT16):	// truncate low word
+	case CASE(TUINT64, TINT16):
+		a = AMOVH;
+		goto trunc64;
+
+	case CASE(TINT64, TUINT16):
+	case CASE(TUINT64, TUINT16):
+		a = AMOVHU;
+		goto trunc64;
+
+	case CASE(TINT32, TINT32):	// same size
+	case CASE(TINT32, TUINT32):
+	case CASE(TUINT32, TINT32):
+	case CASE(TUINT32, TUINT32):
+		a = AMOVW;
+		break;
+
+	case CASE(TINT64, TINT32):	// truncate
+	case CASE(TUINT64, TINT32):
+	case CASE(TINT64, TUINT32):
+	case CASE(TUINT64, TUINT32):
+		split64(f, &flo, &fhi);
+		regalloc(&r1, t->type, N);
+		gins(AMOVW, &flo, &r1);
+		gins(AMOVW, &r1, t);
+		regfree(&r1);
+		splitclean();
+		return;
+
+	case CASE(TINT64, TINT64):	// same size
+	case CASE(TINT64, TUINT64):
+	case CASE(TUINT64, TINT64):
+	case CASE(TUINT64, TUINT64):
+		split64(f, &flo, &fhi);
+		split64(t, &tlo, &thi);
+		regalloc(&r1, flo.type, N);
+		regalloc(&r2, fhi.type, N);
+		gins(AMOVW, &flo, &r1);
+		gins(AMOVW, &fhi, &r2);
+		gins(AMOVW, &r1, &tlo);
+		gins(AMOVW, &r2, &thi);
+		regfree(&r1);
+		regfree(&r2);
+		splitclean();
+		splitclean();
+		return;
+
+	/*
+	 * integer up-conversions
+	 */
+	case CASE(TINT8, TINT16):	// sign extend int8
+	case CASE(TINT8, TUINT16):
+	case CASE(TINT8, TINT32):
+	case CASE(TINT8, TUINT32):
+		a = AMOVB;
+		goto rdst;
+	case CASE(TINT8, TINT64):	// convert via int32
+	case CASE(TINT8, TUINT64):
+		cvt = types[TINT32];
+		goto hard;
+
+	case CASE(TUINT8, TINT16):	// zero extend uint8
+	case CASE(TUINT8, TUINT16):
+	case CASE(TUINT8, TINT32):
+	case CASE(TUINT8, TUINT32):
+		a = AMOVBU;
+		goto rdst;
+	case CASE(TUINT8, TINT64):	// convert via uint32
+	case CASE(TUINT8, TUINT64):
+		cvt = types[TUINT32];
+		goto hard;
+
+	case CASE(TINT16, TINT32):	// sign extend int16
+	case CASE(TINT16, TUINT32):
+		a = AMOVH;
+		goto rdst;
+	case CASE(TINT16, TINT64):	// convert via int32
+	case CASE(TINT16, TUINT64):
+		cvt = types[TINT32];
+		goto hard;
+
+	case CASE(TUINT16, TINT32):	// zero extend uint16
+	case CASE(TUINT16, TUINT32):
+		a = AMOVHU;
+		goto rdst;
+	case CASE(TUINT16, TINT64):	// convert via uint32
+	case CASE(TUINT16, TUINT64):
+		cvt = types[TUINT32];
+		goto hard;
+
+	case CASE(TINT32, TINT64):	// sign extend int32
+	case CASE(TINT32, TUINT64):
+		split64(t, &tlo, &thi);
+		regalloc(&r1, tlo.type, N);
+		regalloc(&r2, thi.type, N);
+		gmove(f, &r1);
+		p1 = gins(AMOVW, &r1, &r2);
+		p1->from.type = D_SHIFT;
+		p1->from.offset = 2 << 5 | 31 << 7 | r1.val.u.reg; // r1->31
+		p1->from.reg = NREG;
+//print("gmove: %P\n", p1);
+		gins(AMOVW, &r1, &tlo);
+		gins(AMOVW, &r2, &thi);
+		regfree(&r1);
+		regfree(&r2);
+		splitclean();
+		return;
+
+	case CASE(TUINT32, TINT64):	// zero extend uint32
+	case CASE(TUINT32, TUINT64):
+		split64(t, &tlo, &thi);
+		gmove(f, &tlo);
+		regalloc(&r1, thi.type, N);
+		gins(AMOVW, ncon(0), &r1);
+		gins(AMOVW, &r1, &thi);
+		regfree(&r1);
+		splitclean();
+		return;
+
+	/*
+	* float to integer
+	*/
+	case CASE(TFLOAT32, TINT8):
+	case CASE(TFLOAT32, TUINT8):
+	case CASE(TFLOAT32, TINT16):
+	case CASE(TFLOAT32, TUINT16):
+	case CASE(TFLOAT32, TINT32):
+	case CASE(TFLOAT32, TUINT32):
+//	case CASE(TFLOAT32, TUINT64):
+
+	case CASE(TFLOAT64, TINT8):
+	case CASE(TFLOAT64, TUINT8):
+	case CASE(TFLOAT64, TINT16):
+	case CASE(TFLOAT64, TUINT16):
+	case CASE(TFLOAT64, TINT32):
+	case CASE(TFLOAT64, TUINT32):
+//	case CASE(TFLOAT64, TUINT64):
+		fa = AMOVF;
+		a = AMOVFW;
+		if(ft == TFLOAT64) {
+			fa = AMOVD;
+			a = AMOVDW;
+		}
+		ta = AMOVW;
+		switch(tt) {
+		case TINT8:
+			ta = AMOVB;
+			break;
+		case TUINT8:
+			ta = AMOVBU;
+			break;
+		case TINT16:
+			ta = AMOVH;
+			break;
+		case TUINT16:
+			ta = AMOVHU;
+			break;
+		}
+
+		regalloc(&r1, types[ft], f);
+		regalloc(&r2, types[tt], t);
+		gins(fa, f, &r1);	// load to fpu
+		p1 = gins(a, &r1, &r1);	// convert to w
+		switch(tt) {
+		case TUINT8:
+		case TUINT16:
+		case TUINT32:
+			p1->scond |= C_UBIT;
+		}
+		gins(AMOVW, &r1, &r2);	// copy to cpu
+		gins(ta, &r2, t);	// store
+		regfree(&r1);
+		regfree(&r2);
+		return;
+
+	/*
+	 * integer to float
+	 */
+	case CASE(TINT8, TFLOAT32):
+	case CASE(TUINT8, TFLOAT32):
+	case CASE(TINT16, TFLOAT32):
+	case CASE(TUINT16, TFLOAT32):
+	case CASE(TINT32, TFLOAT32):
+	case CASE(TUINT32, TFLOAT32):
+	case CASE(TINT8, TFLOAT64):
+	case CASE(TUINT8, TFLOAT64):
+	case CASE(TINT16, TFLOAT64):
+	case CASE(TUINT16, TFLOAT64):
+	case CASE(TINT32, TFLOAT64):
+	case CASE(TUINT32, TFLOAT64):
+		fa = AMOVW;
+		switch(ft) {
+		case TINT8:
+			fa = AMOVB;
+			break;
+		case TUINT8:
+			fa = AMOVBU;
+			break;
+		case TINT16:
+			fa = AMOVH;
+			break;
+		case TUINT16:
+			fa = AMOVHU;
+			break;
+		}
+		a = AMOVWF;
+		ta = AMOVF;
+		if(tt == TFLOAT64) {
+			a = AMOVWD;
+			ta = AMOVD;
+		}
+		regalloc(&r1, types[ft], f);
+		regalloc(&r2, types[tt], t);
+		gins(fa, f, &r1);	// load to cpu
+		gins(AMOVW, &r1, &r2);	// copy to fpu
+		p1 = gins(a, &r2, &r2);	// convert
+		switch(ft) {
+		case TUINT8:
+		case TUINT16:
+		case TUINT32:
+			p1->scond |= C_UBIT;
+		}
+		gins(ta, &r2, t);	// store
+		regfree(&r1);
+		regfree(&r2);
+		return;
+
+	case CASE(TUINT64, TFLOAT32):
+	case CASE(TUINT64, TFLOAT64):
+		fatal("gmove UINT64, TFLOAT not implemented");
+		return;
+
+
+	/*
+	 * float to float
+	 */
+	case CASE(TFLOAT32, TFLOAT32):
+		a = AMOVF;
+		break;
+
+	case CASE(TFLOAT64, TFLOAT64):
+		a = AMOVD;
+		break;
+
+	case CASE(TFLOAT32, TFLOAT64):
+		regalloc(&r1, types[TFLOAT64], t);
+		gins(AMOVF, f, &r1);
+		gins(AMOVFD, &r1, &r1);
+		gins(AMOVD, &r1, t);
+		regfree(&r1);
+		return;
+
+	case CASE(TFLOAT64, TFLOAT32):
+		regalloc(&r1, types[TFLOAT64], t);
+		gins(AMOVD, f, &r1);
+		gins(AMOVDF, &r1, &r1);
+		gins(AMOVF, &r1, t);
+		regfree(&r1);
+		return;
+	}
+
+	gins(a, f, t);
+	return;
+
+rdst:
+	// TODO(kaib): we almost always require a register dest anyway, this can probably be
+	// removed.
+	// requires register destination
+	regalloc(&r1, t->type, t);
+	gins(a, f, &r1);
+	gmove(&r1, t);
+	regfree(&r1);
+	return;
+
+hard:
+	// requires register intermediate
+	regalloc(&r1, cvt, t);
+	gmove(f, &r1);
+	gmove(&r1, t);
+	regfree(&r1);
+	return;
+
+trunc64:
+	// truncate 64 bit integer
+	split64(f, &flo, &fhi);
+	regalloc(&r1, t->type, N);
+	gins(a, &flo, &r1);
+	gins(a, &r1, t);
+	regfree(&r1);
+	splitclean();
+	return;
+
+fatal:
+	// should not happen
+	fatal("gmove %N -> %N", f, t);
+}
+
+int
+samaddr(Node *f, Node *t)
+{
+
+	if(f->op != t->op)
+		return 0;
+
+	switch(f->op) {
+	case OREGISTER:
+		if(f->val.u.reg != t->val.u.reg)
+			break;
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * generate one instruction:
+ *	as f, t
+ */
+Prog*
+gins(int as, Node *f, Node *t)
+{
+//	Node nod;
+//	int32 v;
+	Prog *p;
+	Addr af, at;
+
+	if(f != N && f->op == OINDEX) {
+		fatal("gins OINDEX not implemented");
+//		regalloc(&nod, &regnode, Z);
+//		v = constnode.vconst;
+//		cgen(f->right, &nod);
+//		constnode.vconst = v;
+//		idx.reg = nod.reg;
+//		regfree(&nod);
+	}
+	if(t != N && t->op == OINDEX) {
+		fatal("gins OINDEX not implemented");
+//		regalloc(&nod, &regnode, Z);
+//		v = constnode.vconst;
+//		cgen(t->right, &nod);
+//		constnode.vconst = v;
+//		idx.reg = nod.reg;
+//		regfree(&nod);
+	}
+
+	memset(&af, 0, sizeof af);
+	memset(&at, 0, sizeof at);
+	if(f != N)
+		naddr(f, &af, 1);
+	if(t != N)
+		naddr(t, &at, 1);	p = prog(as);
+	if(f != N)
+		p->from = af;
+	if(t != N)
+		p->to = at;
+	if(debug['g'])
+		print("%P\n", p);
+	return p;
+}
+
+/*
+ * insert n into reg slot of p
+ */
+void
+raddr(Node *n, Prog *p)
+{
+	Addr a;
+
+	naddr(n, &a, 1);
+	if(a.type != D_REG && a.type != D_FREG) {
+		if(n)
+			fatal("bad in raddr: %O", n->op);
+		else
+			fatal("bad in raddr: <null>");
+		p->reg = NREG;
+	} else
+		p->reg = a.reg;
+}
+
+/* generate a comparison
+TODO(kaib): one of the args can actually be a small constant. relax the constraint and fix call sites.
+ */
+Prog*
+gcmp(int as, Node *lhs, Node *rhs)
+{
+	Prog *p;
+
+	if(lhs->op != OREGISTER || rhs->op != OREGISTER)
+		fatal("bad operands to gcmp: %O %O", lhs->op, rhs->op);
+
+	p = gins(as, rhs, N);
+	raddr(lhs, p);
+	return p;
+}
+
+/* generate a constant shift
+ * arm encodes a shift by 32 as 0, thus asking for 0 shift is illegal.
+*/
+Prog*
+gshift(int as, Node *lhs, int32 stype, int32 sval, Node *rhs)
+{
+	Prog *p;
+
+	if(sval <= 0 || sval > 32)
+		fatal("bad shift value: %d", sval);
+
+	sval = sval&0x1f;
+
+	p = gins(as, N, rhs);
+	p->from.type = D_SHIFT;
+	p->from.offset = stype | sval<<7 | lhs->val.u.reg;
+	return p;
+}
+
+/* generate a register shift
+*/
+Prog *
+gregshift(int as, Node *lhs, int32 stype, Node *reg, Node *rhs)
+{
+	Prog *p;
+	p = gins(as, N, rhs);
+	p->from.type = D_SHIFT;
+	p->from.offset = stype | reg->val.u.reg << 8 | 1<<4 | lhs->val.u.reg;
+	return p;
+}
+
+static void
+checkoffset(Addr *a, int canemitcode)
+{
+	Prog *p;
+	Node n1;
+
+	if(a->offset < unmappedzero)
+		return;
+	if(!canemitcode)
+		fatal("checkoffset %#x, cannot emit code", a->offset);
+
+	// cannot rely on unmapped nil page at 0 to catch
+	// reference with large offset.  instead, emit explicit
+	// test of 0(reg).
+	regalloc(&n1, types[TUINTPTR], N);
+	p = gins(AMOVW, N, &n1);
+	p->from = *a;
+	p->from.offset = 0;
+	regfree(&n1);
+}
+
+/*
+ * generate code to compute n;
+ * make a refer to result.
+ */
+void
+naddr(Node *n, Addr *a, int canemitcode)
+{
+	a->type = D_NONE;
+	a->name = D_NONE;
+	a->reg = NREG;
+	a->node = N;
+	a->etype = 0;
+	if(n == N)
+		return;
+
+	switch(n->op) {
+	default:
+		fatal("naddr: bad %O %D", n->op, a);
+		break;
+
+	case OREGISTER:
+		if(n->val.u.reg <= REGALLOC_RMAX) {
+			a->type = D_REG;
+			a->reg = n->val.u.reg;
+		} else {
+			a->type = D_FREG;
+			a->reg = n->val.u.reg - REGALLOC_F0;
+		}
+		a->sym = S;
+		break;
+
+	case OINDEX:
+	case OIND:
+		fatal("naddr: OINDEX");
+//		naddr(n->left, a);
+//		if(a->type >= D_AX && a->type <= D_DI)
+//			a->type += D_INDIR;
+//		else
+//		if(a->type == D_CONST)
+//			a->type = D_NONE+D_INDIR;
+//		else
+//		if(a->type == D_ADDR) {
+//			a->type = a->index;
+//			a->index = D_NONE;
+//		} else
+//			goto bad;
+//		if(n->op == OINDEX) {
+//			a->index = idx.reg;
+//			a->scale = n->scale;
+//		}
+//		break;
+
+	case OINDREG:
+		a->type = D_OREG;
+		a->reg = n->val.u.reg;
+		a->sym = n->sym;
+		a->offset = n->xoffset;
+		checkoffset(a, canemitcode);
+		break;
+
+	case OPARAM:
+		// n->left is PHEAP ONAME for stack parameter.
+		// compute address of actual parameter on stack.
+		a->etype = simtype[n->left->type->etype];
+		a->width = n->left->type->width;
+		a->offset = n->xoffset;
+		a->sym = n->left->sym;
+		a->type = D_OREG;
+		a->name = D_PARAM;
+		break;
+
+	case ONAME:
+		a->etype = 0;
+		a->width = 0;
+		a->reg = NREG;
+		if(n->type != T) {
+			a->etype = simtype[n->type->etype];
+			a->width = n->type->width;
+		}
+		a->pun = n->pun;
+		a->offset = n->xoffset;
+		a->sym = n->sym;
+		if(a->sym == S)
+			a->sym = lookup(".noname");
+		if(n->method) {
+			if(n->type != T)
+			if(n->type->sym != S)
+			if(n->type->sym->pkg != nil)
+				a->sym = pkglookup(a->sym->name, n->type->sym->pkg);
+		}
+
+		a->type = D_OREG;
+		switch(n->class) {
+		default:
+			fatal("naddr: ONAME class %S %d\n", n->sym, n->class);
+		case PEXTERN:
+			a->name = D_EXTERN;
+			break;
+		case PAUTO:
+			a->name = D_AUTO;
+			if (n->sym)
+				a->node = n->orig;
+			break;
+		case PPARAM:
+		case PPARAMOUT:
+			a->name = D_PARAM;
+			break;
+		case PFUNC:
+			a->name = D_EXTERN;
+			a->type = D_CONST;
+			break;
+		}
+		break;
+
+	case OLITERAL:
+		switch(n->val.ctype) {
+		default:
+			fatal("naddr: const %lT", n->type);
+			break;
+		case CTFLT:
+			a->type = D_FCONST;
+			a->dval = mpgetflt(n->val.u.fval);
+			break;
+		case CTINT:
+			a->sym = S;
+			a->type = D_CONST;
+			a->offset = mpgetfix(n->val.u.xval);
+			break;
+		case CTSTR:
+			datagostring(n->val.u.sval, a);
+			break;
+		case CTBOOL:
+			a->sym = S;
+			a->type = D_CONST;
+			a->offset = n->val.u.bval;
+			break;
+		case CTNIL:
+			a->sym = S;
+			a->type = D_CONST;
+			a->offset = 0;
+			break;
+		}
+		break;
+
+	case OLEN:
+		// len of string or slice
+		naddr(n->left, a, canemitcode);
+		a->etype = TINT32;
+		if(a->type == D_CONST && a->offset == 0)
+			break;	// len(nil)
+		a->offset += Array_nel;
+		if(a->offset >= unmappedzero && a->offset-Array_nel < unmappedzero)
+			checkoffset(a, canemitcode);
+		break;
+
+	case OCAP:
+		// cap of string or slice
+		naddr(n->left, a, canemitcode);
+		a->etype = TINT32;
+		if(a->type == D_CONST && a->offset == 0)
+			break;	// cap(nil)
+		a->offset += Array_cap;
+		if(a->offset >= unmappedzero && a->offset-Array_cap < unmappedzero)
+			checkoffset(a, canemitcode);
+		break;
+
+	case OADDR:
+		naddr(n->left, a, canemitcode);
+		a->etype = tptr;
+		switch(a->type) {
+		case D_OREG:
+			a->type = D_CONST;
+			break;
+
+		case D_REG:
+		case D_CONST:
+			break;
+		
+		default:
+			fatal("naddr: OADDR %d\n", a->type);
+		}
+	}
+}
+
+/*
+ * return Axxx for Oxxx on type t.
+ */
+int
+optoas(int op, Type *t)
+{
+	int a;
+
+	if(t == T)
+		fatal("optoas: t is nil");
+
+	a = AGOK;
+	switch(CASE(op, simtype[t->etype])) {
+	default:
+		fatal("optoas: no entry %O-%T etype %T simtype %T", op, t, types[t->etype], types[simtype[t->etype]]);
+		break;
+
+/*	case CASE(OADDR, TPTR32):
+		a = ALEAL;
+		break;
+
+	case CASE(OADDR, TPTR64):
+		a = ALEAQ;
+		break;
+*/
+	// TODO(kaib): make sure the conditional branches work on all edge cases
+	case CASE(OEQ, TBOOL):
+	case CASE(OEQ, TINT8):
+	case CASE(OEQ, TUINT8):
+	case CASE(OEQ, TINT16):
+	case CASE(OEQ, TUINT16):
+	case CASE(OEQ, TINT32):
+	case CASE(OEQ, TUINT32):
+	case CASE(OEQ, TINT64):
+	case CASE(OEQ, TUINT64):
+	case CASE(OEQ, TPTR32):
+	case CASE(OEQ, TPTR64):
+	case CASE(OEQ, TFLOAT32):
+	case CASE(OEQ, TFLOAT64):
+		a = ABEQ;
+		break;
+
+	case CASE(ONE, TBOOL):
+	case CASE(ONE, TINT8):
+	case CASE(ONE, TUINT8):
+	case CASE(ONE, TINT16):
+	case CASE(ONE, TUINT16):
+	case CASE(ONE, TINT32):
+	case CASE(ONE, TUINT32):
+	case CASE(ONE, TINT64):
+	case CASE(ONE, TUINT64):
+	case CASE(ONE, TPTR32):
+	case CASE(ONE, TPTR64):
+	case CASE(ONE, TFLOAT32):
+	case CASE(ONE, TFLOAT64):
+		a = ABNE;
+		break;
+
+	case CASE(OLT, TINT8):
+	case CASE(OLT, TINT16):
+	case CASE(OLT, TINT32):
+	case CASE(OLT, TINT64):
+	case CASE(OLT, TFLOAT32):
+	case CASE(OLT, TFLOAT64):
+		a = ABLT;
+		break;
+
+	case CASE(OLT, TUINT8):
+	case CASE(OLT, TUINT16):
+	case CASE(OLT, TUINT32):
+	case CASE(OLT, TUINT64):
+		a = ABLO;
+		break;
+
+	case CASE(OLE, TINT8):
+	case CASE(OLE, TINT16):
+	case CASE(OLE, TINT32):
+	case CASE(OLE, TINT64):
+	case CASE(OLE, TFLOAT32):
+	case CASE(OLE, TFLOAT64):
+		a = ABLE;
+		break;
+
+	case CASE(OLE, TUINT8):
+	case CASE(OLE, TUINT16):
+	case CASE(OLE, TUINT32):
+	case CASE(OLE, TUINT64):
+		a = ABLS;
+		break;
+
+	case CASE(OGT, TINT8):
+	case CASE(OGT, TINT16):
+	case CASE(OGT, TINT32):
+	case CASE(OGT, TINT64):
+	case CASE(OGT, TFLOAT32):
+	case CASE(OGT, TFLOAT64):
+		a = ABGT;
+		break;
+
+	case CASE(OGT, TUINT8):
+	case CASE(OGT, TUINT16):
+	case CASE(OGT, TUINT32):
+	case CASE(OGT, TUINT64):
+		a = ABHI;
+		break;
+
+	case CASE(OGE, TINT8):
+	case CASE(OGE, TINT16):
+	case CASE(OGE, TINT32):
+	case CASE(OGE, TINT64):
+	case CASE(OGE, TFLOAT32):
+	case CASE(OGE, TFLOAT64):
+		a = ABGE;
+		break;
+
+	case CASE(OGE, TUINT8):
+	case CASE(OGE, TUINT16):
+	case CASE(OGE, TUINT32):
+	case CASE(OGE, TUINT64):
+		a = ABHS;
+		break;
+
+	case CASE(OCMP, TBOOL):
+	case CASE(OCMP, TINT8):
+	case CASE(OCMP, TUINT8):
+	case CASE(OCMP, TINT16):
+	case CASE(OCMP, TUINT16):
+	case CASE(OCMP, TINT32):
+	case CASE(OCMP, TUINT32):
+	case CASE(OCMP, TPTR32):
+		a = ACMP;
+		break;
+
+	case CASE(OCMP, TFLOAT32):
+		a = ACMPF;
+		break;
+
+	case CASE(OCMP, TFLOAT64):
+		a = ACMPD;
+		break;
+
+	case CASE(OAS, TBOOL):
+	case CASE(OAS, TINT8):
+		a = AMOVB;
+		break;
+
+	case CASE(OAS, TUINT8):
+		a = AMOVBU;
+		break;
+
+	case CASE(OAS, TINT16):
+		a = AMOVH;
+		break;
+
+	case CASE(OAS, TUINT16):
+		a = AMOVHU;
+		break;
+
+	case CASE(OAS, TINT32):
+	case CASE(OAS, TUINT32):
+	case CASE(OAS, TPTR32):
+		a = AMOVW;
+		break;
+
+	case CASE(OAS, TFLOAT32):
+		a = AMOVF;
+		break;
+
+	case CASE(OAS, TFLOAT64):
+		a = AMOVD;
+		break;
+
+	case CASE(OADD, TINT8):
+	case CASE(OADD, TUINT8):
+	case CASE(OADD, TINT16):
+	case CASE(OADD, TUINT16):
+	case CASE(OADD, TINT32):
+	case CASE(OADD, TUINT32):
+	case CASE(OADD, TPTR32):
+		a = AADD;
+		break;
+
+	case CASE(OADD, TFLOAT32):
+		a = AADDF;
+		break;
+
+	case CASE(OADD, TFLOAT64):
+		a = AADDD;
+		break;
+
+	case CASE(OSUB, TINT8):
+	case CASE(OSUB, TUINT8):
+	case CASE(OSUB, TINT16):
+	case CASE(OSUB, TUINT16):
+	case CASE(OSUB, TINT32):
+	case CASE(OSUB, TUINT32):
+	case CASE(OSUB, TPTR32):
+		a = ASUB;
+		break;
+
+	case CASE(OSUB, TFLOAT32):
+		a = ASUBF;
+		break;
+
+	case CASE(OSUB, TFLOAT64):
+		a = ASUBD;
+		break;
+
+	case CASE(OAND, TINT8):
+	case CASE(OAND, TUINT8):
+	case CASE(OAND, TINT16):
+	case CASE(OAND, TUINT16):
+	case CASE(OAND, TINT32):
+	case CASE(OAND, TUINT32):
+	case CASE(OAND, TPTR32):
+		a = AAND;
+		break;
+
+	case CASE(OOR, TINT8):
+	case CASE(OOR, TUINT8):
+	case CASE(OOR, TINT16):
+	case CASE(OOR, TUINT16):
+	case CASE(OOR, TINT32):
+	case CASE(OOR, TUINT32):
+	case CASE(OOR, TPTR32):
+		a = AORR;
+		break;
+
+	case CASE(OXOR, TINT8):
+	case CASE(OXOR, TUINT8):
+	case CASE(OXOR, TINT16):
+	case CASE(OXOR, TUINT16):
+	case CASE(OXOR, TINT32):
+	case CASE(OXOR, TUINT32):
+	case CASE(OXOR, TPTR32):
+		a = AEOR;
+		break;
+
+	case CASE(OLSH, TINT8):
+	case CASE(OLSH, TUINT8):
+	case CASE(OLSH, TINT16):
+	case CASE(OLSH, TUINT16):
+	case CASE(OLSH, TINT32):
+	case CASE(OLSH, TUINT32):
+	case CASE(OLSH, TPTR32):
+		a = ASLL;
+		break;
+
+	case CASE(ORSH, TUINT8):
+	case CASE(ORSH, TUINT16):
+	case CASE(ORSH, TUINT32):
+	case CASE(ORSH, TPTR32):
+		a = ASRL;
+		break;
+
+	case CASE(ORSH, TINT8):
+	case CASE(ORSH, TINT16):
+	case CASE(ORSH, TINT32):
+		a = ASRA;
+		break;
+
+	case CASE(OMUL, TUINT8):
+	case CASE(OMUL, TUINT16):
+	case CASE(OMUL, TUINT32):
+	case CASE(OMUL, TPTR32):
+		a = AMULU;
+		break;
+
+	case CASE(OMUL, TINT8):
+	case CASE(OMUL, TINT16):
+	case CASE(OMUL, TINT32):
+		a = AMUL;
+		break;
+
+	case CASE(OMUL, TFLOAT32):
+		a = AMULF;
+		break;
+
+	case CASE(OMUL, TFLOAT64):
+		a = AMULD;
+		break;
+
+	case CASE(ODIV, TUINT8):
+	case CASE(ODIV, TUINT16):
+	case CASE(ODIV, TUINT32):
+	case CASE(ODIV, TPTR32):
+		a = ADIVU;
+		break;
+
+	case CASE(ODIV, TINT8):
+	case CASE(ODIV, TINT16):
+	case CASE(ODIV, TINT32):
+		a = ADIV;
+		break;
+
+	case CASE(OMOD, TUINT8):
+	case CASE(OMOD, TUINT16):
+	case CASE(OMOD, TUINT32):
+	case CASE(OMOD, TPTR32):
+		a = AMODU;
+		break;
+
+	case CASE(OMOD, TINT8):
+	case CASE(OMOD, TINT16):
+	case CASE(OMOD, TINT32):
+		a = AMOD;
+		break;
+
+//	case CASE(OEXTEND, TINT16):
+//		a = ACWD;
+//		break;
+
+//	case CASE(OEXTEND, TINT32):
+//		a = ACDQ;
+//		break;
+
+//	case CASE(OEXTEND, TINT64):
+//		a = ACQO;
+//		break;
+
+	case CASE(ODIV, TFLOAT32):
+		a = ADIVF;
+		break;
+
+	case CASE(ODIV, TFLOAT64):
+		a = ADIVD;
+		break;
+
+	}
+	return a;
+}
+
+enum
+{
+	ODynam	= 1<<0,
+	OPtrto	= 1<<1,
+};
+
+static	Node	clean[20];
+static	int	cleani = 0;
+
+void
+sudoclean(void)
+{
+	if(clean[cleani-1].op != OEMPTY)
+		regfree(&clean[cleani-1]);
+	if(clean[cleani-2].op != OEMPTY)
+		regfree(&clean[cleani-2]);
+	cleani -= 2;
+}
+
+int
+dotaddable(Node *n, Node *n1)
+{
+	int o, oary[10];
+	Node *nn;
+
+	if(n->op != ODOT)
+		return 0;
+
+	o = dotoffset(n, oary, &nn);
+	if(nn != N && nn->addable && o == 1 && oary[0] >= 0) {
+		*n1 = *nn;
+		n1->type = n->type;
+		n1->xoffset += oary[0];
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * generate code to compute address of n,
+ * a reference to a (perhaps nested) field inside
+ * an array or struct.
+ * return 0 on failure, 1 on success.
+ * on success, leaves usable address in a.
+ *
+ * caller is responsible for calling sudoclean
+ * after successful sudoaddable,
+ * to release the register used for a.
+ */
+int
+sudoaddable(int as, Node *n, Addr *a, int *w)
+{
+	int o, i;
+	int oary[10];
+	int64 v;
+	Node n1, n2, n3, n4, *nn, *l, *r;
+	Node *reg, *reg1;
+	Prog *p1, *p2;
+	Type *t;
+
+	if(n->type == T)
+		return 0;
+
+	switch(n->op) {
+	case OLITERAL:
+		if(n->val.ctype != CTINT)
+			break;
+		v = mpgetfix(n->val.u.xval);
+		if(v >= 32000 || v <= -32000)
+			break;
+		goto lit;
+
+	case ODOT:
+	case ODOTPTR:
+		cleani += 2;
+		reg = &clean[cleani-1];
+		reg1 = &clean[cleani-2];
+		reg->op = OEMPTY;
+		reg1->op = OEMPTY;
+		goto odot;
+
+	case OINDEX:
+		if(n->left->type->etype == TSTRING)
+			return 0;
+		cleani += 2;
+		reg = &clean[cleani-1];
+		reg1 = &clean[cleani-2];
+		reg->op = OEMPTY;
+		reg1->op = OEMPTY;
+		goto oindex;
+	}
+	return 0;
+
+lit:
+	switch(as) {
+	default:
+		return 0;
+	case AADD: case ASUB: case AAND: case AORR: case AEOR:
+	case AMOVB: case AMOVBU: case AMOVH: case AMOVHU:
+	case AMOVW:
+		break;
+	}
+
+	cleani += 2;
+	reg = &clean[cleani-1];
+	reg1 = &clean[cleani-2];
+	reg->op = OEMPTY;
+	reg1->op = OEMPTY;
+	naddr(n, a, 1);
+	goto yes;
+
+odot:
+	o = dotoffset(n, oary, &nn);
+	if(nn == N)
+		goto no;
+
+	if(nn->addable && o == 1 && oary[0] >= 0) {
+		// directly addressable set of DOTs
+		n1 = *nn;
+		n1.type = n->type;
+		n1.xoffset += oary[0];
+		naddr(&n1, a, 1);
+		goto yes;
+	}
+
+	regalloc(reg, types[tptr], N);
+	n1 = *reg;
+	n1.op = OINDREG;
+	if(oary[0] >= 0) {
+		agen(nn, reg);
+		n1.xoffset = oary[0];
+	} else {
+		cgen(nn, reg);
+		n1.xoffset = -(oary[0]+1);
+	}
+
+	for(i=1; i<o; i++) {
+		if(oary[i] >= 0)
+			fatal("cant happen");
+		gins(AMOVW, &n1, reg);
+		n1.xoffset = -(oary[i]+1);
+	}
+
+	a->type = D_NONE;
+	a->name = D_NONE;
+	n1.type = n->type;
+	naddr(&n1, a, 1);
+	goto yes;
+
+oindex:
+	l = n->left;
+	r = n->right;
+	if(l->ullman >= UINF && r->ullman >= UINF)
+		goto no;
+
+	// set o to type of array
+	o = 0;
+	if(isptr[l->type->etype]) {
+		o += OPtrto;
+		if(l->type->type->etype != TARRAY)
+			fatal("not ptr ary");
+		if(l->type->type->bound < 0)
+			o += ODynam;
+	} else {
+		if(l->type->etype != TARRAY)
+			fatal("not ary");
+		if(l->type->bound < 0)
+			o += ODynam;
+	}
+
+	*w = n->type->width;
+	if(isconst(r, CTINT))
+		goto oindex_const;
+
+	switch(*w) {
+	default:
+		goto no;
+	case 1:
+	case 2:
+	case 4:
+	case 8:
+		break;
+	}
+
+	// load the array (reg)
+	if(l->ullman > r->ullman) {
+		regalloc(reg, types[tptr], N);
+		if(o & OPtrto)
+			cgen(l, reg);
+		else
+			agen(l, reg);
+	}
+
+	// load the index (reg1)
+	t = types[TUINT32];
+	if(issigned[r->type->etype])
+		t = types[TINT32];
+	regalloc(reg1, t, N);
+	regalloc(&n3, types[TINT32], reg1);
+	p2 = cgenindex(r, &n3);
+	gmove(&n3, reg1);
+	regfree(&n3);
+
+	// load the array (reg)
+	if(l->ullman <= r->ullman) {
+		regalloc(reg, types[tptr], N);
+		if(o & OPtrto)
+			cgen(l, reg);
+		else
+			agen(l, reg);
+	}
+
+	// check bounds
+	if(!debug['B']) {
+		if(o & ODynam) {
+			n2 = *reg;
+			n2.op = OINDREG;
+			n2.type = types[tptr];
+			n2.xoffset = Array_nel;
+		} else {
+			if(l->type->width >= unmappedzero && l->op == OIND) {
+				// cannot rely on page protections to
+				// catch array ptr == 0, so dereference.
+				n2 = *reg;
+				n2.op = OINDREG;
+				n2.type = types[TUINTPTR];
+				n2.xoffset = 0;
+				regalloc(&n3, n2.type, N);
+				gins(AMOVW, &n2, &n3);
+				regfree(&n3);
+			}
+			nodconst(&n2, types[TUINT32], l->type->bound);
+			if(o & OPtrto)
+				nodconst(&n2, types[TUINT32], l->type->type->bound);
+		}
+		regalloc(&n3, n2.type, N);
+		cgen(&n2, &n3);
+		gcmp(optoas(OCMP, types[TUINT32]), reg1, &n3);
+		regfree(&n3);
+		p1 = gbranch(optoas(OLT, types[TUINT32]), T);
+		if(p2)
+			patch(p2, pc);
+		ginscall(panicindex, 0);
+		patch(p1, pc);
+	}
+
+	if(o & ODynam) {
+		n2 = *reg;
+		n2.op = OINDREG;
+		n2.type = types[tptr];
+		n2.xoffset = Array_array;
+		gmove(&n2, reg);
+	}
+
+	switch(*w) {
+	case 1:
+		gins(AADD, reg1, reg);
+		break;
+	case 2:
+		gshift(AADD, reg1, SHIFT_LL, 1, reg);
+		break;
+	case 4:
+		gshift(AADD, reg1, SHIFT_LL, 2, reg);
+		break;
+	case 8:
+		gshift(AADD, reg1, SHIFT_LL, 3, reg);
+		break;
+	}
+
+	naddr(reg1, a, 1);
+	a->type = D_OREG;
+	a->reg = reg->val.u.reg;
+	a->offset = 0;
+	goto yes;
+
+oindex_const:
+	// index is constant
+	// can check statically and
+	// can multiply by width statically
+
+	regalloc(reg, types[tptr], N);
+	if(o & OPtrto)
+		cgen(l, reg);
+	else
+		agen(l, reg);
+
+	v = mpgetfix(r->val.u.xval);
+	if(o & ODynam) {
+
+		if(!debug['B'] && !n->etype) {
+			n1 = *reg;
+			n1.op = OINDREG;
+			n1.type = types[tptr];
+			n1.xoffset = Array_nel;
+			nodconst(&n2, types[TUINT32], v);
+			regalloc(&n3, types[TUINT32], N);
+			cgen(&n2, &n3);
+			regalloc(&n4, n1.type, N);
+			cgen(&n1, &n4);
+			gcmp(optoas(OCMP, types[TUINT32]), &n4, &n3);
+			regfree(&n4);
+			regfree(&n3);
+			p1 = gbranch(optoas(OGT, types[TUINT32]), T);
+			ginscall(panicindex, 0);
+			patch(p1, pc);
+		}
+
+		n1 = *reg;
+		n1.op = OINDREG;
+		n1.type = types[tptr];
+		n1.xoffset = Array_array;
+		gmove(&n1, reg);
+	}
+
+	n2 = *reg;
+	n2.op = OINDREG;
+	n2.xoffset = v * (*w);
+	a->type = D_NONE;
+	a->name = D_NONE;
+	naddr(&n2, a, 1);
+	goto yes;
+
+yes:
+	return 1;
+
+no:
+	sudoclean();
+	return 0;
+}
diff --git a/src/cmd/5g/list.c b/src/cmd/5g/list.c
new file mode 100644
index 000000000..0c6dbbf71
--- /dev/null
+++ b/src/cmd/5g/list.c
@@ -0,0 +1,331 @@
+// Derived from Inferno utils/5c/list.c
+// http://code.google.com/p/inferno-os/source/browse/utils/5c/list.c
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include "gg.h"
+
+// TODO(kaib): make 5g/list.c congruent with 5l/list.c
+
+static	int	sconsize;
+void
+listinit(void)
+{
+
+	fmtinstall('A', Aconv);		// as
+	fmtinstall('C', Cconv);		// conditional execution bit
+	fmtinstall('P', Pconv);			// Prog*
+	fmtinstall('D', Dconv);		// Addr*
+	fmtinstall('Y', Yconv);		// sconst
+	fmtinstall('R', Rconv);		// register
+	fmtinstall('M', Mconv);		// names
+}
+
+int
+Pconv(Fmt *fp)
+{
+	char str[STRINGSZ], str1[STRINGSZ];
+	Prog *p;
+
+	p = va_arg(fp->args, Prog*);
+	sconsize = 8;
+	switch(p->as) {
+	default:
+		snprint(str1, sizeof(str1), "%A%C", p->as, p->scond);
+		if(p->reg == NREG)
+			snprint(str, sizeof(str), "%.4d (%L) %-7s	%D,%D", 
+				p->loc, p->lineno, str1, &p->from, &p->to);
+		else
+		if (p->from.type != D_FREG) {
+			snprint(str, sizeof(str), "%.4d (%L) %-7s	%D,R%d,%D", 
+				p->loc, p->lineno, str1, &p->from, p->reg, &p->to);
+		} else
+			snprint(str, sizeof(str), "%.4d (%L) %-7A%C	%D,F%d,%D",
+				p->loc, p->lineno, p->as, p->scond, &p->from, p->reg, &p->to);
+		break;
+
+	case ADATA:
+		snprint(str, sizeof(str), "%.4d (%L) %-7A	%D/%d,%D",
+			p->loc, p->lineno, p->as, &p->from, p->reg, &p->to);
+		break;
+	}
+	return fmtstrcpy(fp, str);
+}
+
+int
+Dconv(Fmt *fp)
+{
+	char str[STRINGSZ];
+	char *op;
+	Addr *a;
+	int i;
+	int32 v;
+
+	a = va_arg(fp->args, Addr*);
+	if(a == A) {
+		sprint(str, "<nil>");
+		goto conv;
+	}
+	i = a->type;
+	switch(i) {
+
+	default:
+		sprint(str, "GOK-type(%d)", a->type);
+		break;
+
+	case D_NONE:
+		str[0] = 0;
+		if(a->name != D_NONE || a->reg != NREG || a->sym != S)
+			sprint(str, "%M(R%d)(NONE)", a, a->reg);
+		break;
+
+	case D_CONST:
+		if(a->reg != NREG)
+			sprint(str, "$%M(R%d)", a, a->reg);
+		else
+			sprint(str, "$%M", a);
+		break;
+
+	case D_CONST2:
+		sprint(str, "$%d-%d", a->offset, a->offset2);
+		break;
+
+	case D_SHIFT:
+		v = a->offset;
+		op = "<<>>->@>" + (((v>>5) & 3) << 1);
+		if(v & (1<<4))
+			sprint(str, "R%d%c%cR%d", v&15, op[0], op[1], (v>>8)&15);
+		else
+			sprint(str, "R%d%c%c%d", v&15, op[0], op[1], (v>>7)&31);
+		if(a->reg != NREG)
+			sprint(str+strlen(str), "(R%d)", a->reg);
+		break;
+
+	case D_OCONST:
+		sprint(str, "$*$%M", a);
+		if(a->reg != NREG)
+			sprint(str, "%M(R%d)(CONST)", a, a->reg);
+		break;
+
+	case D_OREG:
+		if(a->reg != NREG)
+			sprint(str, "%M(R%d)", a, a->reg);
+		else
+			sprint(str, "%M", a);
+		break;
+
+	case D_REG:
+		sprint(str, "R%d", a->reg);
+		if(a->name != D_NONE || a->sym != S)
+			sprint(str, "%M(R%d)(REG)", a, a->reg);
+		break;
+
+	case D_REGREG:
+		sprint(str, "(R%d,R%d)", a->reg, (int)a->offset);
+		if(a->name != D_NONE || a->sym != S)
+			sprint(str, "%M(R%d)(REG)", a, a->reg);
+		break;
+
+	case D_FREG:
+		sprint(str, "F%d", a->reg);
+		if(a->name != D_NONE || a->sym != S)
+			sprint(str, "%M(R%d)(REG)", a, a->reg);
+		break;
+
+	case D_BRANCH:
+		if(a->branch == P || a->branch->loc == 0) {
+			if(a->sym != S)
+				sprint(str, "%s+%d(APC)", a->sym->name, a->offset);
+			else
+				sprint(str, "%d(APC)", a->offset);
+		} else
+			if(a->sym != S)
+				sprint(str, "%s+%d(APC)", a->sym->name, a->branch->loc);
+			else
+				sprint(str, "%d(APC)", a->branch->loc);
+		break;
+
+	case D_FCONST:
+		snprint(str, sizeof(str), "$(%.17e)", a->dval);
+		break;
+
+	case D_SCONST:
+		snprint(str, sizeof(str), "$\"%Y\"", a->sval);
+		break;
+
+		// TODO(kaib): Add back
+//	case D_ADDR:
+//		a->type = a->index;
+//		a->index = D_NONE;
+//		snprint(str, sizeof(str), "$%D", a);
+//		a->index = a->type;
+//		a->type = D_ADDR;
+//		goto conv;
+	}
+conv:
+	return fmtstrcpy(fp, str);
+}
+
+int
+Aconv(Fmt *fp)
+{
+	int i;
+
+	i = va_arg(fp->args, int);
+	return fmtstrcpy(fp, anames[i]);
+}
+
+char*	strcond[16] =
+{
+	".EQ",
+	".NE",
+	".HS",
+	".LO",
+	".MI",
+	".PL",
+	".VS",
+	".VC",
+	".HI",
+	".LS",
+	".GE",
+	".LT",
+	".GT",
+	".LE",
+	"",
+	".NV"
+};
+
+int
+Cconv(Fmt *fp)
+{
+	char s[STRINGSZ];
+	int c;
+
+	c = va_arg(fp->args, int);
+	strcpy(s, strcond[c & C_SCOND]);
+	if(c & C_SBIT)
+		strcat(s, ".S");
+	if(c & C_PBIT)
+		strcat(s, ".P");
+	if(c & C_WBIT)
+		strcat(s, ".W");
+	if(c & C_UBIT)		/* ambiguous with FBIT */
+		strcat(s, ".U");
+	return fmtstrcpy(fp, s);
+}
+
+int
+Yconv(Fmt *fp)
+{
+	int i, c;
+	char str[STRINGSZ], *p, *a;
+
+	a = va_arg(fp->args, char*);
+	p = str;
+	for(i=0; i<sconsize; i++) {
+		c = a[i] & 0xff;
+		if((c >= 'a' && c <= 'z') ||
+		   (c >= 'A' && c <= 'Z') ||
+		   (c >= '0' && c <= '9')) {
+			*p++ = c;
+			continue;
+		}
+		*p++ = '\\';
+		switch(c) {
+		default:
+			if(c < 040 || c >= 0177)
+				break;	/* not portable */
+			p[-1] = c;
+			continue;
+		case 0:
+			*p++ = 'z';
+			continue;
+		case '\\':
+		case '"':
+			*p++ = c;
+			continue;
+		case '\n':
+			*p++ = 'n';
+			continue;
+		case '\t':
+			*p++ = 't';
+			continue;
+		}
+		*p++ = (c>>6) + '0';
+		*p++ = ((c>>3) & 7) + '0';
+		*p++ = (c & 7) + '0';
+	}
+	*p = 0;
+	return fmtstrcpy(fp, str);
+}
+
+int
+Rconv(Fmt *fp)
+{
+	int r;
+	char str[STRINGSZ];
+
+	r = va_arg(fp->args, int);
+	snprint(str, sizeof(str), "R%d", r);
+	return fmtstrcpy(fp, str);
+}
+
+int
+Mconv(Fmt *fp)
+{
+	char str[STRINGSZ];
+	Addr *a;
+
+	a = va_arg(fp->args, Addr*);
+	switch(a->name) {
+	default:
+		snprint(str, sizeof(str),  "GOK-name(%d)", a->name);
+		break;
+
+	case D_NONE:
+		snprint(str, sizeof(str), "%d", a->offset);
+		break;
+
+	case D_EXTERN:
+		snprint(str, sizeof(str), "%S+%d(SB)", a->sym, a->offset);
+		break;
+
+	case D_STATIC:
+		snprint(str, sizeof(str), "%S<>+%d(SB)", a->sym, a->offset);
+		break;
+
+	case D_AUTO:
+		snprint(str, sizeof(str), "%S+%d(SP)", a->sym, a->offset);
+		break;
+
+	case D_PARAM:
+		snprint(str, sizeof(str), "%S+%d(FP)", a->sym, a->offset);
+		break;
+	}
+	return fmtstrcpy(fp, str);
+}
diff --git a/src/cmd/5g/opt.h b/src/cmd/5g/opt.h
new file mode 100644
index 000000000..7a0070fc9
--- /dev/null
+++ b/src/cmd/5g/opt.h
@@ -0,0 +1,165 @@
+// Inferno utils/5c/gc.h
+// http://code.google.com/p/inferno-os/source/browse/utils/5c/gc.h
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#define	Z	N
+#define	Adr	Addr
+
+#define	D_HI	D_NONE
+#define	D_LO	D_NONE
+
+#define	isregtype(t)	((t)>= D_AX && (t)<=D_R15)
+
+#define	BLOAD(r)	band(bnot(r->refbehind), r->refahead)
+#define	BSTORE(r)	band(bnot(r->calbehind), r->calahead)
+#define	LOAD(r)		(~r->refbehind.b[z] & r->refahead.b[z])
+#define	STORE(r)	(~r->calbehind.b[z] & r->calahead.b[z])
+
+#define	CLOAD	5
+#define	CREF	5
+#define	CINF	1000
+#define	LOOP	3
+
+typedef	struct	Reg	Reg;
+typedef	struct	Rgn	Rgn;
+
+struct	Reg
+{
+
+	Bits	set;
+	Bits	use1;
+	Bits	use2;
+
+	Bits	refbehind;
+	Bits	refahead;
+	Bits	calbehind;
+	Bits	calahead;
+	Bits	regdiff;
+	Bits	act;
+
+	int32	regu;		// register used bitmap
+	int32	rpo;		// reverse post ordering
+	int32	active;
+
+	uint16	loop;		// x5 for every loop
+	uchar	refset;		// diagnostic generated
+
+	Reg*	p1;
+	Reg*	p2;
+	Reg*	p2link;
+	Reg*	s1;
+	Reg*	s2;
+	Reg*	link;
+	Prog*	prog;
+};
+#define	R	((Reg*)0)
+
+#define	NRGN	600
+struct	Rgn
+{
+	Reg*	enter;
+	short	cost;
+	short	varno;
+	short	regno;
+};
+
+EXTERN	int32	exregoffset;		// not set
+EXTERN	int32	exfregoffset;		// not set
+EXTERN	Reg*	firstr;
+EXTERN	Reg*	lastr;
+EXTERN	Reg	zreg;
+EXTERN	Reg*	freer;
+EXTERN	Reg**	rpo2r;
+EXTERN	Rgn	region[NRGN];
+EXTERN	Rgn*	rgp;
+EXTERN	int	nregion;
+EXTERN	int	nvar;
+EXTERN	int32	regbits;
+EXTERN	int32	exregbits;
+EXTERN	Bits	externs;
+EXTERN	Bits	params;
+EXTERN	Bits	consts;
+EXTERN	Bits	addrs;
+EXTERN	Bits	ovar;
+EXTERN	int	change;
+EXTERN	int32	maxnr;
+EXTERN	int32*	idom;
+
+EXTERN	struct
+{
+	int32	ncvtreg;
+	int32	nspill;
+	int32	nreload;
+	int32	ndelmov;
+	int32	nvar;
+	int32	naddr;
+} ostats;
+
+/*
+ * reg.c
+ */
+Reg*	rega(void);
+int	rcmp(const void*, const void*);
+void	regopt(Prog*);
+void	addmove(Reg*, int, int, int);
+Bits	mkvar(Reg *r, Adr *a);
+void	prop(Reg*, Bits, Bits);
+void	loopit(Reg*, int32);
+void	synch(Reg*, Bits);
+uint32	allreg(uint32, Rgn*);
+void	paint1(Reg*, int);
+uint32	paint2(Reg*, int);
+void	paint3(Reg*, int, int32, int);
+void	addreg(Adr*, int);
+void	dumpit(char *str, Reg *r0);
+int	noreturn(Prog *p);
+
+/*
+ * peep.c
+ */
+void	peep(void);
+void	excise(Reg*);
+Reg*	uniqp(Reg*);
+Reg*	uniqs(Reg*);
+int	regtyp(Adr*);
+int	anyvar(Adr*);
+int	subprop(Reg*);
+int	copyprop(Reg*);
+int	copy1(Adr*, Adr*, Reg*, int);
+int	copyu(Prog*, Adr*, Adr*);
+
+int	copyas(Adr*, Adr*);
+int	copyau(Adr*, Adr*);
+int	copysub(Adr*, Adr*, Adr*, int);
+int	copysub1(Prog*, Adr*, Adr*, int);
+
+int32	RtoB(int);
+int32	FtoB(int);
+int	BtoR(int32);
+int	BtoF(int32);
diff --git a/src/cmd/5g/peep.c b/src/cmd/5g/peep.c
new file mode 100644
index 000000000..6cc93db12
--- /dev/null
+++ b/src/cmd/5g/peep.c
@@ -0,0 +1,1521 @@
+// Inferno utils/5c/peep.c
+// http://code.google.com/p/inferno-os/source/browse/utils/5g/peep.c
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+
+#include "gg.h"
+#include "opt.h"
+
+int	xtramodes(Reg*, Adr*);
+int	shiftprop(Reg *r);
+void	constprop(Adr *c1, Adr *v1, Reg *r);
+void	predicate(void);
+int	copyau1(Prog *p, Adr *v);
+int	isdconst(Addr *a);
+
+void
+peep(void)
+{
+	Reg *r, *r1, *r2;
+	Prog *p, *p1;
+	int t;
+/*
+ * complete R structure
+ */
+	for(r=firstr; r!=R; r=r1) {
+		r1 = r->link;
+		if(r1 == R)
+			break;
+		p = r->prog->link;
+		while(p != r1->prog)
+		switch(p->as) {
+		default:
+			r2 = rega();
+			r->link = r2;
+			r2->link = r1;
+
+			r2->prog = p;
+			r2->p1 = r;
+			r->s1 = r2;
+			r2->s1 = r1;
+			r1->p1 = r2;
+
+			r = r2;
+
+		case ADATA:
+		case AGLOBL:
+		case ANAME:
+		case ASIGNAME:
+			p = p->link;
+		}
+	}
+//dumpit("begin", firstr);
+
+loop1:
+
+	t = 0;
+	for(r=firstr; r!=R; r=r->link) {
+		p = r->prog;
+		switch(p->as) {
+		case ASLL:
+		case ASRL:
+		case ASRA:
+			/*
+			 * elide shift into D_SHIFT operand of subsequent instruction
+			 */
+//			if(shiftprop(r)) {
+//				excise(r);
+//				t++;
+//				break;
+//			}
+			break;
+
+		case AMOVW:
+		case AMOVF:
+		case AMOVD:
+			if(regtyp(&p->from))
+			if(p->from.type == p->to.type)
+			if(p->scond == C_SCOND_NONE) {
+				if(copyprop(r)) {
+					excise(r);
+					t++;
+					break;
+				}
+				if(subprop(r) && copyprop(r)) {
+					excise(r);
+					t++;
+					break;
+				}
+			}
+			break;
+
+			if(p->scond == C_SCOND_NONE)
+			if(regtyp(&p->to))
+			if(isdconst(&p->from)) {
+				constprop(&p->from, &p->to, r->s1);
+			}
+			break;
+		}
+	}
+	if(t)
+		goto loop1;
+
+return;
+
+	for(r=firstr; r!=R; r=r->link) {
+		p = r->prog;
+		switch(p->as) {
+//		case AEOR:
+//			/*
+//			 * EOR -1,x,y => MVN x,y
+//			 */
+//			if(isdconst(&p->from) && p->from.offset == -1) {
+//				p->as = AMVN;
+//				p->from.type = D_REG;
+//				if(p->reg != NREG)
+//					p->from.reg = p->reg;
+//				else
+//					p->from.reg = p->to.reg;
+//				p->reg = NREG;
+//			}
+//			break;
+
+		case AMOVH:
+		case AMOVHU:
+		case AMOVB:
+		case AMOVBU:
+			/*
+			 * look for MOVB x,R; MOVB R,R
+			 */
+			if(p->to.type != D_REG)
+				break;
+			if(r1 == R)
+				break;
+			p1 = r1->prog;
+			if(p1->as != p->as)
+				break;
+			if(p1->from.type != D_REG || p1->from.reg != p->to.reg)
+				break;
+			if(p1->to.type != D_REG || p1->to.reg != p->to.reg)
+				break;
+			excise(r1);
+			break;
+		}
+		r1 = r->link;
+	}
+
+//	for(r=firstr; r!=R; r=r->link) {
+//		p = r->prog;
+//		switch(p->as) {
+//		case AMOVW:
+//		case AMOVB:
+//		case AMOVBU:
+//			if(p->from.type == D_OREG && p->from.offset == 0)
+//				xtramodes(r, &p->from);
+//			else
+//			if(p->to.type == D_OREG && p->to.offset == 0)
+//				xtramodes(r, &p->to);
+//			else
+//				continue;
+//			break;
+//		case ACMP:
+//			/*
+//			 * elide CMP $0,x if calculation of x can set condition codes
+//			 */
+//			if(isdconst(&p->from) || p->from.offset != 0)
+//				continue;
+//			r2 = r->s1;
+//			if(r2 == R)
+//				continue;
+//			t = r2->prog->as;
+//			switch(t) {
+//			default:
+//				continue;
+//			case ABEQ:
+//			case ABNE:
+//			case ABMI:
+//			case ABPL:
+//				break;
+//			case ABGE:
+//				t = ABPL;
+//				break;
+//			case ABLT:
+//				t = ABMI;
+//				break;
+//			case ABHI:
+//				t = ABNE;
+//				break;
+//			case ABLS:
+//				t = ABEQ;
+//				break;
+//			}
+//			r1 = r;
+//			do
+//				r1 = uniqp(r1);
+//			while (r1 != R && r1->prog->as == ANOP);
+//			if(r1 == R)
+//				continue;
+//			p1 = r1->prog;
+//			if(p1->to.type != D_REG)
+//				continue;
+//			if(p1->to.reg != p->reg)
+//			if(!(p1->as == AMOVW && p1->from.type == D_REG && p1->from.reg == p->reg))
+//				continue;
+//
+//			switch(p1->as) {
+//			default:
+//				continue;
+//			case AMOVW:
+//				if(p1->from.type != D_REG)
+//					continue;
+//			case AAND:
+//			case AEOR:
+//			case AORR:
+//			case ABIC:
+//			case AMVN:
+//			case ASUB:
+//			case ARSB:
+//			case AADD:
+//			case AADC:
+//			case ASBC:
+//			case ARSC:
+//				break;
+//			}
+//			p1->scond |= C_SBIT;
+//			r2->prog->as = t;
+//			excise(r);
+//			continue;
+//		}
+//	}
+
+	predicate();
+}
+
+Reg*
+uniqp(Reg *r)
+{
+	Reg *r1;
+
+	r1 = r->p1;
+	if(r1 == R) {
+		r1 = r->p2;
+		if(r1 == R || r1->p2link != R)
+			return R;
+	} else
+		if(r->p2 != R)
+			return R;
+	return r1;
+}
+
+Reg*
+uniqs(Reg *r)
+{
+	Reg *r1;
+
+	r1 = r->s1;
+	if(r1 == R) {
+		r1 = r->s2;
+		if(r1 == R)
+			return R;
+	} else
+		if(r->s2 != R)
+			return R;
+	return r1;
+}
+
+int
+regtyp(Adr *a)
+{
+
+	if(a->type == D_REG)
+		return 1;
+	if(a->type == D_FREG)
+		return 1;
+	return 0;
+}
+
+/*
+ * the idea is to substitute
+ * one register for another
+ * from one MOV to another
+ *	MOV	a, R0
+ *	ADD	b, R0	/ no use of R1
+ *	MOV	R0, R1
+ * would be converted to
+ *	MOV	a, R1
+ *	ADD	b, R1
+ *	MOV	R1, R0
+ * hopefully, then the former or latter MOV
+ * will be eliminated by copy propagation.
+ */
+int
+subprop(Reg *r0)
+{
+	Prog *p;
+	Adr *v1, *v2;
+	Reg *r;
+	int t;
+
+	p = r0->prog;
+	v1 = &p->from;
+	if(!regtyp(v1))
+		return 0;
+	v2 = &p->to;
+	if(!regtyp(v2))
+		return 0;
+	for(r=uniqp(r0); r!=R; r=uniqp(r)) {
+		if(uniqs(r) == R)
+			break;
+		p = r->prog;
+		switch(p->as) {
+		case ABL:
+			return 0;
+
+		case AMULLU:
+		case AMULA:
+		case AMVN:
+			return 0;
+
+		case ACMN:
+		case AADD:
+		case ASUB:
+		case ASBC:
+		case ARSB:
+		case ASLL:
+		case ASRL:
+		case ASRA:
+		case AORR:
+		case AAND:
+		case AEOR:
+		case AMUL:
+		case AMULU:
+		case ADIV:
+		case ADIVU:
+		case AMOD:
+		case AMODU:
+
+		case AADDD:
+		case AADDF:
+		case ASUBD:
+		case ASUBF:
+		case AMULD:
+		case AMULF:
+		case ADIVD:
+		case ADIVF:
+			if(p->to.type == v1->type)
+			if(p->to.reg == v1->reg)
+			if(p->scond == C_SCOND_NONE) {
+				if(p->reg == NREG)
+					p->reg = p->to.reg;
+				goto gotit;
+			}
+			break;
+
+		case AMOVF:
+		case AMOVD:
+		case AMOVW:
+			if(p->to.type == v1->type)
+			if(p->to.reg == v1->reg)
+			if(p->scond == C_SCOND_NONE)
+				goto gotit;
+			break;
+
+		case AMOVM:
+			t = 1<<v2->reg;
+			if((p->from.type == D_CONST && (p->from.offset&t)) ||
+			   (p->to.type == D_CONST && (p->to.offset&t)))
+				return 0;
+			break;
+		}
+		if(copyau(&p->from, v2) ||
+		   copyau1(p, v2) ||
+		   copyau(&p->to, v2))
+			break;
+		if(copysub(&p->from, v1, v2, 0) ||
+		   copysub1(p, v1, v2, 0) ||
+		   copysub(&p->to, v1, v2, 0))
+			break;
+	}
+	return 0;
+
+gotit:
+	copysub(&p->to, v1, v2, 1);
+	if(debug['P']) {
+		print("gotit: %D->%D\n%P", v1, v2, r->prog);
+		if(p->from.type == v2->type)
+			print(" excise");
+		print("\n");
+	}
+	for(r=uniqs(r); r!=r0; r=uniqs(r)) {
+		p = r->prog;
+		copysub(&p->from, v1, v2, 1);
+		copysub1(p, v1, v2, 1);
+		copysub(&p->to, v1, v2, 1);
+		if(debug['P'])
+			print("%P\n", r->prog);
+	}
+	t = v1->reg;
+	v1->reg = v2->reg;
+	v2->reg = t;
+	if(debug['P'])
+		print("%P last\n", r->prog);
+	return 1;
+}
+
+/*
+ * The idea is to remove redundant copies.
+ *	v1->v2	F=0
+ *	(use v2	s/v2/v1/)*
+ *	set v1	F=1
+ *	use v2	return fail
+ *	-----------------
+ *	v1->v2	F=0
+ *	(use v2	s/v2/v1/)*
+ *	set v1	F=1
+ *	set v2	return success
+ */
+int
+copyprop(Reg *r0)
+{
+	Prog *p;
+	Adr *v1, *v2;
+	Reg *r;
+
+	p = r0->prog;
+	v1 = &p->from;
+	v2 = &p->to;
+	if(copyas(v1, v2))
+		return 1;
+	for(r=firstr; r!=R; r=r->link)
+		r->active = 0;
+	return copy1(v1, v2, r0->s1, 0);
+}
+
+int
+copy1(Adr *v1, Adr *v2, Reg *r, int f)
+{
+	int t;
+	Prog *p;
+
+	if(r->active) {
+		if(debug['P'])
+			print("act set; return 1\n");
+		return 1;
+	}
+	r->active = 1;
+	if(debug['P'])
+		print("copy %D->%D f=%d\n", v1, v2, f);
+	for(; r != R; r = r->s1) {
+		p = r->prog;
+		if(debug['P'])
+			print("%P", p);
+		if(!f && uniqp(r) == R) {
+			f = 1;
+			if(debug['P'])
+				print("; merge; f=%d", f);
+		}
+		t = copyu(p, v2, A);
+		switch(t) {
+		case 2:	/* rar, cant split */
+			if(debug['P'])
+				print("; %Drar; return 0\n", v2);
+			return 0;
+
+		case 3:	/* set */
+			if(debug['P'])
+				print("; %Dset; return 1\n", v2);
+			return 1;
+
+		case 1:	/* used, substitute */
+		case 4:	/* use and set */
+			if(f) {
+				if(!debug['P'])
+					return 0;
+				if(t == 4)
+					print("; %Dused+set and f=%d; return 0\n", v2, f);
+				else
+					print("; %Dused and f=%d; return 0\n", v2, f);
+				return 0;
+			}
+			if(copyu(p, v2, v1)) {
+				if(debug['P'])
+					print("; sub fail; return 0\n");
+				return 0;
+			}
+			if(debug['P'])
+				print("; sub%D/%D", v2, v1);
+			if(t == 4) {
+				if(debug['P'])
+					print("; %Dused+set; return 1\n", v2);
+				return 1;
+			}
+			break;
+		}
+		if(!f) {
+			t = copyu(p, v1, A);
+			if(!f && (t == 2 || t == 3 || t == 4)) {
+				f = 1;
+				if(debug['P'])
+					print("; %Dset and !f; f=%d", v1, f);
+			}
+		}
+		if(debug['P'])
+			print("\n");
+		if(r->s2)
+			if(!copy1(v1, v2, r->s2, f))
+				return 0;
+	}
+	return 1;
+}
+
+/*
+ * The idea is to remove redundant constants.
+ *	$c1->v1
+ *	($c1->v2 s/$c1/v1)*
+ *	set v1  return
+ * The v1->v2 should be eliminated by copy propagation.
+ */
+void
+constprop(Adr *c1, Adr *v1, Reg *r)
+{
+	Prog *p;
+
+	if(debug['P'])
+		print("constprop %D->%D\n", c1, v1);
+	for(; r != R; r = r->s1) {
+		p = r->prog;
+		if(debug['P'])
+			print("%P", p);
+		if(uniqp(r) == R) {
+			if(debug['P'])
+				print("; merge; return\n");
+			return;
+		}
+		if(p->as == AMOVW && copyas(&p->from, c1)) {
+				if(debug['P'])
+					print("; sub%D/%D", &p->from, v1);
+				p->from = *v1;
+		} else if(copyu(p, v1, A) > 1) {
+			if(debug['P'])
+				print("; %Dset; return\n", v1);
+			return;
+		}
+		if(debug['P'])
+			print("\n");
+		if(r->s2)
+			constprop(c1, v1, r->s2);
+	}
+}
+
+/*
+ * ASLL x,y,w
+ * .. (not use w, not set x y w)
+ * AXXX w,a,b (a != w)
+ * .. (not use w)
+ * (set w)
+ * ----------- changed to
+ * ..
+ * AXXX (x<<y),a,b
+ * ..
+ */
+#define FAIL(msg) { if(debug['P']) print("\t%s; FAILURE\n", msg); return 0; }
+int
+shiftprop(Reg *r)
+{
+	Reg *r1;
+	Prog *p, *p1, *p2;
+	int n, o;
+	Adr a;
+
+	p = r->prog;
+	if(p->to.type != D_REG)
+		FAIL("BOTCH: result not reg");
+	n = p->to.reg;
+	a = zprog.from;
+	if(p->reg != NREG && p->reg != p->to.reg) {
+		a.type = D_REG;
+		a.reg = p->reg;
+	}
+	if(debug['P'])
+		print("shiftprop\n%P", p);
+	r1 = r;
+	for(;;) {
+		/* find first use of shift result; abort if shift operands or result are changed */
+		r1 = uniqs(r1);
+		if(r1 == R)
+			FAIL("branch");
+		if(uniqp(r1) == R)
+			FAIL("merge");
+		p1 = r1->prog;
+		if(debug['P'])
+			print("\n%P", p1);
+		switch(copyu(p1, &p->to, A)) {
+		case 0:	/* not used or set */
+			if((p->from.type == D_REG && copyu(p1, &p->from, A) > 1) ||
+			   (a.type == D_REG && copyu(p1, &a, A) > 1))
+				FAIL("args modified");
+			continue;
+		case 3:	/* set, not used */
+			FAIL("BOTCH: noref");
+		}
+		break;
+	}
+	/* check whether substitution can be done */
+	switch(p1->as) {
+	default:
+		FAIL("non-dpi");
+	case AAND:
+	case AEOR:
+	case AADD:
+	case AADC:
+	case AORR:
+	case ASUB:
+	case ASBC:
+	case ARSB:
+	case ARSC:
+		if(p1->reg == n || (p1->reg == NREG && p1->to.type == D_REG && p1->to.reg == n)) {
+			if(p1->from.type != D_REG)
+				FAIL("can't swap");
+			p1->reg = p1->from.reg;
+			p1->from.reg = n;
+			switch(p1->as) {
+			case ASUB:
+				p1->as = ARSB;
+				break;
+			case ARSB:
+				p1->as = ASUB;
+				break;
+			case ASBC:
+				p1->as = ARSC;
+				break;
+			case ARSC:
+				p1->as = ASBC;
+				break;
+			}
+			if(debug['P'])
+				print("\t=>%P", p1);
+		}
+	case ABIC:
+	case ATST:
+	case ACMP:
+	case ACMN:
+		if(p1->reg == n)
+			FAIL("can't swap");
+		if(p1->reg == NREG && p1->to.reg == n)
+			FAIL("shift result used twice");
+//	case AMVN:
+		if(p1->from.type == D_SHIFT)
+			FAIL("shift result used in shift");
+		if(p1->from.type != D_REG || p1->from.reg != n)
+			FAIL("BOTCH: where is it used?");
+		break;
+	}
+	/* check whether shift result is used subsequently */
+	p2 = p1;
+	if(p1->to.reg != n)
+	for (;;) {
+		r1 = uniqs(r1);
+		if(r1 == R)
+			FAIL("inconclusive");
+		p1 = r1->prog;
+		if(debug['P'])
+			print("\n%P", p1);
+		switch(copyu(p1, &p->to, A)) {
+		case 0:	/* not used or set */
+			continue;
+		case 3: /* set, not used */
+			break;
+		default:/* used */
+			FAIL("reused");
+		}
+		break;
+	}
+
+	/* make the substitution */
+	p2->from.type = D_SHIFT;
+	p2->from.reg = NREG;
+	o = p->reg;
+	if(o == NREG)
+		o = p->to.reg;
+
+	switch(p->from.type){
+	case D_CONST:
+		o |= (p->from.offset&0x1f)<<7;
+		break;
+	case D_REG:
+		o |= (1<<4) | (p->from.reg<<8);
+		break;
+	}
+	switch(p->as){
+	case ASLL:
+		o |= 0<<5;
+		break;
+	case ASRL:
+		o |= 1<<5;
+		break;
+	case ASRA:
+		o |= 2<<5;
+		break;
+	}
+	p2->from.offset = o;
+	if(debug['P'])
+		print("\t=>%P\tSUCCEED\n", p2);
+	return 1;
+}
+
+Reg*
+findpre(Reg *r, Adr *v)
+{
+	Reg *r1;
+
+	for(r1=uniqp(r); r1!=R; r=r1,r1=uniqp(r)) {
+		if(uniqs(r1) != r)
+			return R;
+		switch(copyu(r1->prog, v, A)) {
+		case 1: /* used */
+		case 2: /* read-alter-rewrite */
+			return R;
+		case 3: /* set */
+		case 4: /* set and used */
+			return r1;
+		}
+	}
+	return R;
+}
+
+Reg*
+findinc(Reg *r, Reg *r2, Adr *v)
+{
+	Reg *r1;
+	Prog *p;
+
+
+	for(r1=uniqs(r); r1!=R && r1!=r2; r=r1,r1=uniqs(r)) {
+		if(uniqp(r1) != r)
+			return R;
+		switch(copyu(r1->prog, v, A)) {
+		case 0: /* not touched */
+			continue;
+		case 4: /* set and used */
+			p = r1->prog;
+			if(p->as == AADD)
+			if(isdconst(&p->from))
+			if(p->from.offset > -4096 && p->from.offset < 4096)
+				return r1;
+		default:
+			return R;
+		}
+	}
+	return R;
+}
+
+int
+nochange(Reg *r, Reg *r2, Prog *p)
+{
+	Adr a[3];
+	int i, n;
+
+	if(r == r2)
+		return 1;
+	n = 0;
+	if(p->reg != NREG && p->reg != p->to.reg) {
+		a[n].type = D_REG;
+		a[n++].reg = p->reg;
+	}
+	switch(p->from.type) {
+	case D_SHIFT:
+		a[n].type = D_REG;
+		a[n++].reg = p->from.offset&0xf;
+	case D_REG:
+		a[n].type = D_REG;
+		a[n++].reg = p->from.reg;
+	}
+	if(n == 0)
+		return 1;
+	for(; r!=R && r!=r2; r=uniqs(r)) {
+		p = r->prog;
+		for(i=0; i<n; i++)
+			if(copyu(p, &a[i], A) > 1)
+				return 0;
+	}
+	return 1;
+}
+
+int
+findu1(Reg *r, Adr *v)
+{
+	for(; r != R; r = r->s1) {
+		if(r->active)
+			return 0;
+		r->active = 1;
+		switch(copyu(r->prog, v, A)) {
+		case 1: /* used */
+		case 2: /* read-alter-rewrite */
+		case 4: /* set and used */
+			return 1;
+		case 3: /* set */
+			return 0;
+		}
+		if(r->s2)
+			if (findu1(r->s2, v))
+				return 1;
+	}
+	return 0;
+}
+
+int
+finduse(Reg *r, Adr *v)
+{
+	Reg *r1;
+
+	for(r1=firstr; r1!=R; r1=r1->link)
+		r1->active = 0;
+	return findu1(r, v);
+}
+
+int
+xtramodes(Reg *r, Adr *a)
+{
+	Reg *r1, *r2, *r3;
+	Prog *p, *p1;
+	Adr v;
+
+	p = r->prog;
+	if(debug['h'] && p->as == AMOVB && p->from.type == D_OREG)	/* byte load */
+		return 0;
+	v = *a;
+	v.type = D_REG;
+	r1 = findpre(r, &v);
+	if(r1 != R) {
+		p1 = r1->prog;
+		if(p1->to.type == D_REG && p1->to.reg == v.reg)
+		switch(p1->as) {
+		case AADD:
+			if(p1->from.type == D_REG ||
+			   (p1->from.type == D_SHIFT && (p1->from.offset&(1<<4)) == 0 &&
+			    (p->as != AMOVB || (a == &p->from && (p1->from.offset&~0xf) == 0))) ||
+			   (p1->from.type == D_CONST &&
+			    p1->from.offset > -4096 && p1->from.offset < 4096))
+			if(nochange(uniqs(r1), r, p1)) {
+				if(a != &p->from || v.reg != p->to.reg)
+				if (finduse(r->s1, &v)) {
+					if(p1->reg == NREG || p1->reg == v.reg)
+						/* pre-indexing */
+						p->scond |= C_WBIT;
+					else return 0;
+				}
+				switch (p1->from.type) {
+				case D_REG:
+					/* register offset */
+					a->type = D_SHIFT;
+					a->offset = p1->from.reg;
+					break;
+				case D_SHIFT:
+					/* scaled register offset */
+					a->type = D_SHIFT;
+				case D_CONST:
+					/* immediate offset */
+					a->offset = p1->from.offset;
+					break;
+				}
+				if(p1->reg != NREG)
+					a->reg = p1->reg;
+				excise(r1);
+				return 1;
+			}
+			break;
+		case AMOVW:
+			if(p1->from.type == D_REG)
+			if((r2 = findinc(r1, r, &p1->from)) != R) {
+			for(r3=uniqs(r2); r3->prog->as==ANOP; r3=uniqs(r3))
+				;
+			if(r3 == r) {
+				/* post-indexing */
+				p1 = r2->prog;
+				a->reg = p1->to.reg;
+				a->offset = p1->from.offset;
+				p->scond |= C_PBIT;
+				if(!finduse(r, &r1->prog->to))
+					excise(r1);
+				excise(r2);
+				return 1;
+			}
+			}
+			break;
+		}
+	}
+	if(a != &p->from || a->reg != p->to.reg)
+	if((r1 = findinc(r, R, &v)) != R) {
+		/* post-indexing */
+		p1 = r1->prog;
+		a->offset = p1->from.offset;
+		p->scond |= C_PBIT;
+		excise(r1);
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * return
+ * 1 if v only used (and substitute),
+ * 2 if read-alter-rewrite
+ * 3 if set
+ * 4 if set and used
+ * 0 otherwise (not touched)
+ */
+int
+copyu(Prog *p, Adr *v, Adr *s)
+{
+	switch(p->as) {
+
+	default:
+		print("copyu: cant find %A\n", p->as);
+		return 2;
+
+	case AMOVM:
+		if(v->type != D_REG)
+			return 0;
+		if(p->from.type == D_CONST) {	/* read reglist, read/rar */
+			if(s != A) {
+				if(p->from.offset&(1<<v->reg))
+					return 1;
+				if(copysub(&p->to, v, s, 1))
+					return 1;
+				return 0;
+			}
+			if(copyau(&p->to, v)) {
+				if(p->scond&C_WBIT)
+					return 2;
+				return 1;
+			}
+			if(p->from.offset&(1<<v->reg))
+				return 1;
+		} else {			/* read/rar, write reglist */
+			if(s != A) {
+				if(p->to.offset&(1<<v->reg))
+					return 1;
+				if(copysub(&p->from, v, s, 1))
+					return 1;
+				return 0;
+			}
+			if(copyau(&p->from, v)) {
+				if(p->scond&C_WBIT)
+					return 2;
+				if(p->to.offset&(1<<v->reg))
+					return 4;
+				return 1;
+			}
+			if(p->to.offset&(1<<v->reg))
+				return 3;
+		}
+		return 0;
+
+	case ANOP:	/* read,, write */
+	case AMOVW:
+	case AMOVF:
+	case AMOVD:
+	case AMOVH:
+	case AMOVHU:
+	case AMOVB:
+	case AMOVBU:
+	case AMOVFW:
+	case AMOVWF:
+	case AMOVDW:
+	case AMOVWD:
+	case AMOVFD:
+	case AMOVDF:
+		if(p->scond&(C_WBIT|C_PBIT))
+		if(v->type == D_REG) {
+			if(p->from.type == D_OREG || p->from.type == D_SHIFT) {
+				if(p->from.reg == v->reg)
+					return 2;
+			} else {
+		  		if(p->to.reg == v->reg)
+					return 2;
+			}
+		}
+		if(s != A) {
+			if(copysub(&p->from, v, s, 1))
+				return 1;
+			if(!copyas(&p->to, v))
+				if(copysub(&p->to, v, s, 1))
+					return 1;
+			return 0;
+		}
+		if(copyas(&p->to, v)) {
+			if(p->scond != C_SCOND_NONE)
+				return 2;
+			if(copyau(&p->from, v))
+				return 4;
+			return 3;
+		}
+		if(copyau(&p->from, v))
+			return 1;
+		if(copyau(&p->to, v))
+			return 1;
+		return 0;
+
+	case AMULLU:	/* read, read, write, write */
+	case AMULA:
+	case AMVN:
+		return 2;
+
+	case AADD:	/* read, read, write */
+	case AADC:
+	case ASUB:
+	case ASBC:
+	case ARSB:
+	case ASLL:
+	case ASRL:
+	case ASRA:
+	case AORR:
+	case AAND:
+	case AEOR:
+	case AMUL:
+	case AMULU:
+	case ADIV:
+	case ADIVU:
+	case AMOD:
+	case AMODU:
+	case AADDF:
+	case AADDD:
+	case ASUBF:
+	case ASUBD:
+	case AMULF:
+	case AMULD:
+	case ADIVF:
+	case ADIVD:
+
+	case ACMPF:	/* read, read, */
+	case ACMPD:
+	case ACMP:
+	case ACMN:
+	case ACASE:
+	case ATST:	/* read,, */
+		if(s != A) {
+			if(copysub(&p->from, v, s, 1))
+				return 1;
+			if(copysub1(p, v, s, 1))
+				return 1;
+			if(!copyas(&p->to, v))
+				if(copysub(&p->to, v, s, 1))
+					return 1;
+			return 0;
+		}
+		if(copyas(&p->to, v)) {
+			if(p->scond != C_SCOND_NONE)
+				return 2;
+			if(p->reg == NREG)
+				p->reg = p->to.reg;
+			if(copyau(&p->from, v))
+				return 4;
+			if(copyau1(p, v))
+				return 4;
+			return 3;
+		}
+		if(copyau(&p->from, v))
+			return 1;
+		if(copyau1(p, v))
+			return 1;
+		if(copyau(&p->to, v))
+			return 1;
+		return 0;
+
+	case ABEQ:	/* read, read */
+	case ABNE:
+	case ABCS:
+	case ABHS:
+	case ABCC:
+	case ABLO:
+	case ABMI:
+	case ABPL:
+	case ABVS:
+	case ABVC:
+	case ABHI:
+	case ABLS:
+	case ABGE:
+	case ABLT:
+	case ABGT:
+	case ABLE:
+		if(s != A) {
+			if(copysub(&p->from, v, s, 1))
+				return 1;
+			return copysub1(p, v, s, 1);
+		}
+		if(copyau(&p->from, v))
+			return 1;
+		if(copyau1(p, v))
+			return 1;
+		return 0;
+
+	case AB:	/* funny */
+		if(s != A) {
+			if(copysub(&p->to, v, s, 1))
+				return 1;
+			return 0;
+		}
+		if(copyau(&p->to, v))
+			return 1;
+		return 0;
+
+	case ARET:	/* funny */
+		if(v->type == D_REG)
+		if(v->reg == REGRET)
+			return 2;
+		if(v->type == D_FREG)
+		if(v->reg == FREGRET)
+			return 2;
+
+	case ABL:	/* funny */
+		if(v->type == D_REG) {
+			if(v->reg <= REGEXT && v->reg > exregoffset)
+				return 2;
+			if(v->reg == (uchar)REGARG)
+				return 2;
+		}
+		if(v->type == D_FREG)
+			if(v->reg <= FREGEXT && v->reg > exfregoffset)
+				return 2;
+
+		if(s != A) {
+			if(copysub(&p->to, v, s, 1))
+				return 1;
+			return 0;
+		}
+		if(copyau(&p->to, v))
+			return 4;
+		return 3;
+
+	case ATEXT:	/* funny */
+		if(v->type == D_REG)
+			if(v->reg == (uchar)REGARG)
+				return 3;
+		return 0;
+	}
+	return 0;
+}
+
+/*
+ * direct reference,
+ * could be set/use depending on
+ * semantics
+ */
+int
+copyas(Adr *a, Adr *v)
+{
+
+	if(regtyp(v)) {
+		if(a->type == v->type)
+		if(a->reg == v->reg)
+			return 1;
+	} else
+	if(v->type == D_CONST) {		/* for constprop */
+		if(a->type == v->type)
+		if(a->name == v->name)
+		if(a->sym == v->sym)
+		if(a->reg == v->reg)
+		if(a->offset == v->offset)
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * either direct or indirect
+ */
+int
+copyau(Adr *a, Adr *v)
+{
+
+	if(copyas(a, v))
+		return 1;
+	if(v->type == D_REG) {
+		if(a->type == D_CONST && a->reg != NREG) {
+			if(a->reg == v->reg)
+				return 1;
+		} else
+		if(a->type == D_OREG) {
+			if(a->reg == v->reg)
+				return 1;
+		} else
+		if(a->type == D_REGREG) {
+			if(a->reg == v->reg)
+				return 1;
+			if(a->offset == v->reg)
+				return 1;
+		} else
+		if(a->type == D_SHIFT) {
+			if((a->offset&0xf) == v->reg)
+				return 1;
+			if((a->offset&(1<<4)) && (a->offset>>8) == v->reg)
+				return 1;
+		}
+	}
+	return 0;
+}
+
+/*
+ * compare v to the center
+ * register in p (p->reg)
+ * the trick is that this
+ * register might be D_REG
+ * D_FREG. there are basically
+ * two cases,
+ *	ADD r,r,r
+ *	CMP r,r,
+ */
+int
+copyau1(Prog *p, Adr *v)
+{
+
+	if(regtyp(v))
+	if(p->reg == v->reg) {
+		if(p->to.type != D_NONE) {
+			if(v->type == p->to.type)
+				return 1;
+			return 0;
+		}
+		if(p->from.type != D_NONE) {
+			if(v->type == p->from.type)
+				return 1;
+			return 0;
+		}
+		print("copyau1: cant tell %P\n", p);
+	}
+	return 0;
+}
+
+/*
+ * substitute s for v in a
+ * return failure to substitute
+ */
+int
+copysub(Adr *a, Adr *v, Adr *s, int f)
+{
+
+	if(f)
+	if(copyau(a, v)) {
+		if(a->type == D_SHIFT) {
+			if((a->offset&0xf) == v->reg)
+				a->offset = (a->offset&~0xf)|s->reg;
+			if((a->offset&(1<<4)) && (a->offset>>8) == v->reg)
+				a->offset = (a->offset&~(0xf<<8))|(s->reg<<8);
+		} else
+		if(a->type == D_REGREG) {
+			if(a->offset == v->reg)
+				a->offset = s->reg;
+			if(a->reg == v->reg)
+				a->reg = s->reg;
+		} else
+			a->reg = s->reg;
+	}
+	return 0;
+}
+
+int
+copysub1(Prog *p1, Adr *v, Adr *s, int f)
+{
+
+	if(f)
+	if(copyau1(p1, v))
+		p1->reg = s->reg;
+	return 0;
+}
+
+struct {
+	int opcode;
+	int notopcode;
+	int scond;
+	int notscond;
+} predinfo[]  = {
+	{ ABEQ,	ABNE,	0x0,	0x1, },
+	{ ABNE,	ABEQ,	0x1,	0x0, },
+	{ ABCS,	ABCC,	0x2,	0x3, },
+	{ ABHS,	ABLO,	0x2,	0x3, },
+	{ ABCC,	ABCS,	0x3,	0x2, },
+	{ ABLO,	ABHS,	0x3,	0x2, },
+	{ ABMI,	ABPL,	0x4,	0x5, },
+	{ ABPL,	ABMI,	0x5,	0x4, },
+	{ ABVS,	ABVC,	0x6,	0x7, },
+	{ ABVC,	ABVS,	0x7,	0x6, },
+	{ ABHI,	ABLS,	0x8,	0x9, },
+	{ ABLS,	ABHI,	0x9,	0x8, },
+	{ ABGE,	ABLT,	0xA,	0xB, },
+	{ ABLT,	ABGE,	0xB,	0xA, },
+	{ ABGT,	ABLE,	0xC,	0xD, },
+	{ ABLE,	ABGT,	0xD,	0xC, },
+};
+
+typedef struct {
+	Reg *start;
+	Reg *last;
+	Reg *end;
+	int len;
+} Joininfo;
+
+enum {
+	Join,
+	Split,
+	End,
+	Branch,
+	Setcond,
+	Toolong
+};
+
+enum {
+	Falsecond,
+	Truecond,
+	Delbranch,
+	Keepbranch
+};
+
+int
+isbranch(Prog *p)
+{
+	return (ABEQ <= p->as) && (p->as <= ABLE);
+}
+
+int
+predicable(Prog *p)
+{
+	switch(p->as) {
+	case ANOP:
+	case AXXX:
+	case ADATA:
+	case AGLOBL:
+	case AGOK:
+	case AHISTORY:
+	case ANAME:
+	case ASIGNAME:
+	case ATEXT:
+	case AWORD:
+	case ABCASE:
+	case ACASE:
+		return 0;
+	}
+	if(isbranch(p))
+		return 0;
+	return 1;
+}
+
+/*
+ * Depends on an analysis of the encodings performed by 5l.
+ * These seem to be all of the opcodes that lead to the "S" bit
+ * being set in the instruction encodings.
+ *
+ * C_SBIT may also have been set explicitly in p->scond.
+ */
+int
+modifiescpsr(Prog *p)
+{
+	switch(p->as) {
+	case AMULLU:
+	case AMULA:
+	case AMULU:
+	case ADIVU:
+
+	case ATEQ:
+	case ACMN:
+	case ATST:
+	case ACMP:
+	case AMUL:
+	case ADIV:
+	case AMOD:
+	case AMODU:
+	case ABL:
+		return 1;
+	}
+	if(p->scond & C_SBIT)
+		return 1;
+	return 0;
+}
+
+/*
+ * Find the maximal chain of instructions starting with r which could
+ * be executed conditionally
+ */
+int
+joinsplit(Reg *r, Joininfo *j)
+{
+	j->start = r;
+	j->last = r;
+	j->len = 0;
+	do {
+		if (r->p2 && (r->p1 || r->p2->p2link)) {
+			j->end = r;
+			return Join;
+		}
+		if (r->s1 && r->s2) {
+			j->end = r;
+			return Split;
+		}
+		j->last = r;
+		if (r->prog->as != ANOP)
+			j->len++;
+		if (!r->s1 && !r->s2) {
+			j->end = r->link;
+			return End;
+		}
+		if (r->s2) {
+			j->end = r->s2;
+			return Branch;
+		}
+		if (modifiescpsr(r->prog)) {
+			j->end = r->s1;
+			return Setcond;
+		}
+		r = r->s1;
+	} while (j->len < 4);
+	j->end = r;
+	return Toolong;
+}
+
+Reg*
+successor(Reg *r)
+{
+	if(r->s1)
+		return r->s1;
+	else
+		return r->s2;
+}
+
+void
+applypred(Reg *rstart, Joininfo *j, int cond, int branch)
+{
+	int pred;
+	Reg *r;
+
+	if(j->len == 0)
+		return;
+	if(cond == Truecond)
+		pred = predinfo[rstart->prog->as - ABEQ].scond;
+	else
+		pred = predinfo[rstart->prog->as - ABEQ].notscond;
+
+	for(r = j->start;; r = successor(r)) {
+		if(r->prog->as == AB) {
+			if(r != j->last || branch == Delbranch)
+				excise(r);
+			else {
+				if(cond == Truecond)
+					r->prog->as = predinfo[rstart->prog->as - ABEQ].opcode;
+				else
+					r->prog->as = predinfo[rstart->prog->as - ABEQ].notopcode;
+			}
+		}
+		else
+		if(predicable(r->prog))
+			r->prog->scond = (r->prog->scond&~C_SCOND)|pred;
+		if(r->s1 != r->link) {
+			r->s1 = r->link;
+			r->link->p1 = r;
+		}
+		if(r == j->last)
+			break;
+	}
+}
+
+void
+predicate(void)
+{
+	Reg *r;
+	int t1, t2;
+	Joininfo j1, j2;
+
+	for(r=firstr; r!=R; r=r->link) {
+		if (isbranch(r->prog)) {
+			t1 = joinsplit(r->s1, &j1);
+			t2 = joinsplit(r->s2, &j2);
+			if(j1.last->link != j2.start)
+				continue;
+			if(j1.end == j2.end)
+			if((t1 == Branch && (t2 == Join || t2 == Setcond)) ||
+			   (t2 == Join && (t1 == Join || t1 == Setcond))) {
+				applypred(r, &j1, Falsecond, Delbranch);
+				applypred(r, &j2, Truecond, Delbranch);
+				excise(r);
+				continue;
+			}
+			if(t1 == End || t1 == Branch) {
+				applypred(r, &j1, Falsecond, Keepbranch);
+				excise(r);
+				continue;
+			}
+		}
+	}
+}
+
+int
+isdconst(Addr *a)
+{
+	if(a->type == D_CONST && a->reg == NREG)
+		return 1;
+	return 0;
+}
diff --git a/src/cmd/5g/reg.c b/src/cmd/5g/reg.c
new file mode 100644
index 000000000..2d2a6d01a
--- /dev/null
+++ b/src/cmd/5g/reg.c
@@ -0,0 +1,1607 @@
+// Inferno utils/5c/reg.c
+// http://code.google.com/p/inferno-os/source/browse/utils/5g/reg.c
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+
+#include "gg.h"
+#include "opt.h"
+
+#define	NREGVAR	24
+#define	REGBITS	((uint32)0xffffff)
+#define	P2R(p)	(Reg*)(p->reg)
+
+	void	addsplits(void);
+	int	noreturn(Prog *p);
+static	int	first	= 0;
+
+Reg*
+rega(void)
+{
+	Reg *r;
+
+	r = freer;
+	if(r == R) {
+		r = mal(sizeof(*r));
+	} else
+		freer = r->link;
+
+	*r = zreg;
+	return r;
+}
+
+int
+rcmp(const void *a1, const void *a2)
+{
+	Rgn *p1, *p2;
+	int c1, c2;
+
+	p1 = (Rgn*)a1;
+	p2 = (Rgn*)a2;
+	c1 = p2->cost;
+	c2 = p1->cost;
+	if(c1 -= c2)
+		return c1;
+	return p2->varno - p1->varno;
+}
+
+static void
+setoutvar(void)
+{
+	Type *t;
+	Node *n;
+	Addr a;
+	Iter save;
+	Bits bit;
+	int z;
+
+	t = structfirst(&save, getoutarg(curfn->type));
+	while(t != T) {
+		n = nodarg(t, 1);
+		a = zprog.from;
+		naddr(n, &a, 0);
+		bit = mkvar(R, &a);
+		for(z=0; z<BITS; z++)
+			ovar.b[z] |= bit.b[z];
+		t = structnext(&save);
+	}
+//if(bany(b))
+//print("ovars = %Q\n", &ovar);
+}
+
+void
+excise(Reg *r)
+{
+	Prog *p;
+
+	p = r->prog;
+	p->as = ANOP;
+	p->scond = zprog.scond;
+	p->from = zprog.from;
+	p->to = zprog.to;
+	p->reg = zprog.reg;
+}
+
+static void
+setaddrs(Bits bit)
+{
+	int i, n;
+	Var *v;
+	Sym *s;
+
+	while(bany(&bit)) {
+		// convert each bit to a variable
+		i = bnum(bit);
+		s = var[i].sym;
+		n = var[i].name;
+		bit.b[i/32] &= ~(1L<<(i%32));
+
+		// disable all pieces of that variable
+		for(i=0; i<nvar; i++) {
+			v = var+i;
+			if(v->sym == s && v->name == n)
+				v->addr = 2;
+		}
+	}
+}
+
+static char* regname[] = {
+	".R0",
+	".R1",
+	".R2",
+	".R3",
+	".R4",
+	".R5",
+	".R6",
+	".R7",
+	".R8",
+	".R9",
+	".R10",
+	".R11",
+	".R12",
+	".R13",
+	".R14",
+	".R15",
+	".F0",
+	".F1",
+	".F2",
+	".F3",
+	".F4",
+	".F5",
+	".F6",
+	".F7",
+};
+
+void
+regopt(Prog *firstp)
+{
+	Reg *r, *r1;
+	Prog *p;
+	int i, z, nr;
+	uint32 vreg;
+	Bits bit;
+	
+	if(first == 0) {
+		fmtinstall('Q', Qconv);
+	}
+
+	first++;
+	if(debug['K']) {
+		if(first != 13)
+			return;
+//		debug['R'] = 2;
+//		debug['P'] = 2;
+		print("optimizing %S\n", curfn->nname->sym);
+	}
+
+	// count instructions
+	nr = 0;
+	for(p=firstp; p!=P; p=p->link)
+		nr++;
+
+	// if too big dont bother
+	if(nr >= 10000) {
+//		print("********** %S is too big (%d)\n", curfn->nname->sym, nr);
+		return;
+	}
+
+	r1 = R;
+	firstr = R;
+	lastr = R;
+
+	/*
+	 * control flow is more complicated in generated go code
+	 * than in generated c code.  define pseudo-variables for
+	 * registers, so we have complete register usage information.
+	 */
+	nvar = NREGVAR;
+	memset(var, 0, NREGVAR*sizeof var[0]);
+	for(i=0; i<NREGVAR; i++)
+		var[i].sym = lookup(regname[i]);
+
+	regbits = RtoB(REGSP)|RtoB(REGLINK)|RtoB(REGPC);
+	for(z=0; z<BITS; z++) {
+		externs.b[z] = 0;
+		params.b[z] = 0;
+		consts.b[z] = 0;
+		addrs.b[z] = 0;
+		ovar.b[z] = 0;
+	}
+
+	// build list of return variables
+	setoutvar();
+
+	/*
+	 * pass 1
+	 * build aux data structure
+	 * allocate pcs
+	 * find use and set of variables
+	 */
+	nr = 0;
+	for(p=firstp; p != P; p = p->link) {
+		switch(p->as) {
+		case ADATA:
+		case AGLOBL:
+		case ANAME:
+		case ASIGNAME:
+			continue;
+		}
+		r = rega();
+		nr++;
+		if(firstr == R) {
+			firstr = r;
+			lastr = r;
+		} else {
+			lastr->link = r;
+			r->p1 = lastr;
+			lastr->s1 = r;
+			lastr = r;
+		}
+		r->prog = p;
+		p->regp = r;
+
+		r1 = r->p1;
+		if(r1 != R) {
+			switch(r1->prog->as) {
+			case ARET:
+			case AB:
+			case ARFE:
+				r->p1 = R;
+				r1->s1 = R;
+			}
+		}
+
+		/*
+		 * left side always read
+		 */
+		bit = mkvar(r, &p->from);
+		for(z=0; z<BITS; z++)
+			r->use1.b[z] |= bit.b[z];
+		
+		/*
+		 * middle always read when present
+		 */
+		if(p->reg != NREG) {
+			if(p->from.type != D_FREG)
+				r->use1.b[0] |= RtoB(p->reg);
+			else
+				r->use1.b[0] |= FtoB(p->reg);
+		}
+
+		/*
+		 * right side depends on opcode
+		 */
+		bit = mkvar(r, &p->to);
+		if(bany(&bit))
+		switch(p->as) {
+		default:
+			yyerror("reg: unknown op: %A", p->as);
+			break;
+		
+		/*
+		 * right side read
+		 */
+		case ATST:
+		case ATEQ:
+		case ACMP:
+		case ACMN:
+		case ACMPD:
+		case ACMPF:
+		rightread:
+			for(z=0; z<BITS; z++)
+				r->use2.b[z] |= bit.b[z];
+			break;
+			
+		/*
+		 * right side read or read+write, depending on middle
+		 *	ADD x, z => z += x
+		 *	ADD x, y, z  => z = x + y
+		 */
+		case AADD:
+		case AAND:
+		case AEOR:
+		case ASUB:
+		case ARSB:
+		case AADC:
+		case ASBC:
+		case ARSC:
+		case AORR:
+		case ABIC:
+		case ASLL:
+		case ASRL:
+		case ASRA:
+		case AMUL:
+		case AMULU:
+		case ADIV:
+		case AMOD:
+		case AMODU:
+		case ADIVU:
+			if(p->reg != NREG)
+				goto rightread;
+			// fall through
+
+		/*
+		 * right side read+write
+		 */
+		case AADDF:
+		case AADDD:
+		case ASUBF:
+		case ASUBD:
+		case AMULF:
+		case AMULD:
+		case ADIVF:
+		case ADIVD:
+		case AMULA:
+		case AMULAL:
+		case AMULALU:
+			for(z=0; z<BITS; z++) {
+				r->use2.b[z] |= bit.b[z];
+				r->set.b[z] |= bit.b[z];
+			}
+			break;
+
+		/*
+		 * right side write
+		 */
+		case ANOP:
+		case AMOVB:
+		case AMOVBU:
+		case AMOVD:
+		case AMOVDF:
+		case AMOVDW:
+		case AMOVF:
+		case AMOVFW:
+		case AMOVH:
+		case AMOVHU:
+		case AMOVW:
+		case AMOVWD:
+		case AMOVWF:
+		case AMVN:
+		case AMULL:
+		case AMULLU:
+			if((p->scond & C_SCOND) != C_SCOND_NONE)
+				for(z=0; z<BITS; z++)
+					r->use2.b[z] |= bit.b[z];
+			for(z=0; z<BITS; z++)
+				r->set.b[z] |= bit.b[z];
+			break;
+
+		/*
+		 * funny
+		 */
+		case ABL:
+			setaddrs(bit);
+			break;
+		}
+
+		if(p->as == AMOVM) {
+			z = p->to.offset;
+			if(p->from.type == D_CONST)
+				z = p->from.offset;
+			for(i=0; z; i++) {
+				if(z&1)
+					regbits |= RtoB(i);
+				z >>= 1;
+			}
+		}
+	}
+	if(firstr == R)
+		return;
+
+	for(i=0; i<nvar; i++) {
+		Var *v = var+i;
+		if(v->addr) {
+			bit = blsh(i);
+			for(z=0; z<BITS; z++)
+				addrs.b[z] |= bit.b[z];
+		}
+
+//		print("bit=%2d addr=%d et=%-6E w=%-2d s=%S + %lld\n",
+//			i, v->addr, v->etype, v->width, v->sym, v->offset);
+	}
+
+	/*
+	 * pass 2
+	 * turn branch references to pointers
+	 * build back pointers
+	 */
+	for(r=firstr; r!=R; r=r->link) {
+		p = r->prog;
+		if(p->to.type == D_BRANCH) {
+			if(p->to.branch == P)
+				fatal("pnil %P", p);
+			r1 = p->to.branch->regp;
+			if(r1 == R)
+				fatal("rnil %P", p);
+			if(r1 == r) {
+				//fatal("ref to self %P", p);
+				continue;
+			}
+			r->s2 = r1;
+			r->p2link = r1->p2;
+			r1->p2 = r;
+		}
+	}
+	if(debug['R']) {
+		p = firstr->prog;
+		print("\n%L %D\n", p->lineno, &p->from);
+		print("	addr = %Q\n", addrs);
+	}
+
+	/*
+	 * pass 2.5
+	 * find looping structure
+	 */
+	for(r = firstr; r != R; r = r->link)
+		r->active = 0;
+	change = 0;
+	loopit(firstr, nr);
+
+	/*
+	 * pass 3
+	 * iterate propagating usage
+	 * 	back until flow graph is complete
+	 */
+loop1:
+	change = 0;
+	for(r = firstr; r != R; r = r->link)
+		r->active = 0;
+	for(r = firstr; r != R; r = r->link)
+		if(r->prog->as == ARET)
+			prop(r, zbits, zbits);
+loop11:
+	/* pick up unreachable code */
+	i = 0;
+	for(r = firstr; r != R; r = r1) {
+		r1 = r->link;
+		if(r1 && r1->active && !r->active) {
+			prop(r, zbits, zbits);
+			i = 1;
+		}
+	}
+	if(i)
+		goto loop11;
+	if(change)
+		goto loop1;
+
+
+	/*
+	 * pass 4
+	 * iterate propagating register/variable synchrony
+	 * 	forward until graph is complete
+	 */
+loop2:
+	change = 0;
+	for(r = firstr; r != R; r = r->link)
+		r->active = 0;
+	synch(firstr, zbits);
+	if(change)
+		goto loop2;
+
+	addsplits();
+
+	if(debug['R'] > 1) {
+		print("\nprop structure:\n");
+		for(r = firstr; r != R; r = r->link) {
+			print("%d:%P", r->loop, r->prog);
+			for(z=0; z<BITS; z++) {
+				bit.b[z] = r->set.b[z] |
+					r->refahead.b[z] | r->calahead.b[z] |
+					r->refbehind.b[z] | r->calbehind.b[z] |
+					r->use1.b[z] | r->use2.b[z];
+				bit.b[z] &= ~addrs.b[z];
+			}
+
+			if(bany(&bit)) {
+				print("\t");
+				if(bany(&r->use1))
+					print(" u1=%Q", r->use1);
+				if(bany(&r->use2))
+					print(" u2=%Q", r->use2);
+				if(bany(&r->set))
+					print(" st=%Q", r->set);
+				if(bany(&r->refahead))
+					print(" ra=%Q", r->refahead);
+				if(bany(&r->calahead))
+					print(" ca=%Q", r->calahead);
+				if(bany(&r->refbehind))
+					print(" rb=%Q", r->refbehind);
+				if(bany(&r->calbehind))
+					print(" cb=%Q", r->calbehind);
+			}
+			print("\n");
+		}
+	}
+
+	/*
+	 * pass 4.5
+	 * move register pseudo-variables into regu.
+	 */
+	for(r = firstr; r != R; r = r->link) {
+		r->regu = (r->refbehind.b[0] | r->set.b[0]) & REGBITS;
+
+		r->set.b[0] &= ~REGBITS;
+		r->use1.b[0] &= ~REGBITS;
+		r->use2.b[0] &= ~REGBITS;
+		r->refbehind.b[0] &= ~REGBITS;
+		r->refahead.b[0] &= ~REGBITS;
+		r->calbehind.b[0] &= ~REGBITS;
+		r->calahead.b[0] &= ~REGBITS;
+		r->regdiff.b[0] &= ~REGBITS;
+		r->act.b[0] &= ~REGBITS;
+	}
+
+	/*
+	 * pass 5
+	 * isolate regions
+	 * calculate costs (paint1)
+	 */
+	r = firstr;
+	if(r) {
+		for(z=0; z<BITS; z++)
+			bit.b[z] = (r->refahead.b[z] | r->calahead.b[z]) &
+			  ~(externs.b[z] | params.b[z] | addrs.b[z] | consts.b[z]);
+		if(bany(&bit) & !r->refset) {
+			// should never happen - all variables are preset
+			if(debug['w'])
+				print("%L: used and not set: %Q\n", r->prog->lineno, bit);
+			r->refset = 1;
+		}
+	}
+
+	for(r = firstr; r != R; r = r->link)
+		r->act = zbits;
+	rgp = region;
+	nregion = 0;
+	for(r = firstr; r != R; r = r->link) {
+		for(z=0; z<BITS; z++)
+			bit.b[z] = r->set.b[z] &
+			  ~(r->refahead.b[z] | r->calahead.b[z] | addrs.b[z]);
+		if(bany(&bit) && !r->refset) {
+			if(debug['w'])
+				print("%L: set and not used: %Q\n", r->prog->lineno, bit);
+			r->refset = 1;
+			excise(r);
+		}
+		for(z=0; z<BITS; z++)
+			bit.b[z] = LOAD(r) & ~(r->act.b[z] | addrs.b[z]);
+		while(bany(&bit)) {
+			i = bnum(bit);
+			rgp->enter = r;
+			rgp->varno = i;
+			change = 0;
+			if(debug['R'] > 1)
+				print("\n");
+			paint1(r, i);
+			bit.b[i/32] &= ~(1L<<(i%32));
+			if(change <= 0) {
+				if(debug['R'])
+					print("%L $%d: %Q\n",
+						r->prog->lineno, change, blsh(i));
+				continue;
+			}
+			rgp->cost = change;
+			nregion++;
+			if(nregion >= NRGN) {
+				if(debug['R'] > 1)
+					print("too many regions\n");
+				goto brk;
+			}
+			rgp++;
+		}
+	}
+brk:
+	qsort(region, nregion, sizeof(region[0]), rcmp);
+
+	/*
+	 * pass 6
+	 * determine used registers (paint2)
+	 * replace code (paint3)
+	 */
+	rgp = region;
+	for(i=0; i<nregion; i++) {
+		bit = blsh(rgp->varno);
+		vreg = paint2(rgp->enter, rgp->varno);
+		vreg = allreg(vreg, rgp);
+		if(debug['R']) {
+			if(rgp->regno >= NREG)
+				print("%L $%d F%d: %Q\n",
+					rgp->enter->prog->lineno,
+					rgp->cost,
+					rgp->regno-NREG,
+					bit);
+			else
+				print("%L $%d R%d: %Q\n",
+					rgp->enter->prog->lineno,
+					rgp->cost,
+					rgp->regno,
+					bit);
+		}
+		if(rgp->regno != 0)
+			paint3(rgp->enter, rgp->varno, vreg, rgp->regno);
+		rgp++;
+	}
+	/*
+	 * pass 7
+	 * peep-hole on basic block
+	 */
+	if(!debug['R'] || debug['P']) {
+		peep();
+	}
+
+	/*
+	 * last pass
+	 * eliminate nops
+	 * free aux structures
+	 * adjust the stack pointer
+	 *	MOVW.W 	R1,-12(R13)			<<- start
+	 *	MOVW   	R0,R1
+	 *	MOVW   	R1,8(R13)
+	 *	MOVW   	$0,R1
+	 *	MOVW   	R1,4(R13)
+	 *	BL     	,runtime.newproc+0(SB)
+	 *	MOVW   	&ft+-32(SP),R7			<<- adjust
+	 *	MOVW   	&j+-40(SP),R6			<<- adjust
+	 *	MOVW   	autotmp_0003+-24(SP),R5		<<- adjust
+	 *	MOVW   	$12(R13),R13			<<- finish
+	 */
+	vreg = 0;
+	for(p = firstp; p != P; p = p->link) {
+		while(p->link != P && p->link->as == ANOP)
+			p->link = p->link->link;
+		if(p->to.type == D_BRANCH)
+			while(p->to.branch != P && p->to.branch->as == ANOP)
+				p->to.branch = p->to.branch->link;
+		if(p->as == AMOVW && p->to.reg == 13) {
+			if(p->scond & C_WBIT) {
+				vreg = -p->to.offset;		// in adjust region
+//				print("%P adjusting %d\n", p, vreg);
+				continue;
+			}
+			if(p->from.type == D_CONST && p->to.type == D_REG) {
+				if(p->from.offset != vreg)
+					print("in and out different\n");
+//				print("%P finish %d\n", p, vreg);
+				vreg = 0;	// done adjust region
+				continue;
+			}
+
+//			print("%P %d %d from type\n", p, p->from.type, D_CONST);
+//			print("%P %d %d to type\n\n", p, p->to.type, D_REG);
+		}
+
+		if(p->as == AMOVW && vreg != 0) {
+			if(p->from.sym != S)
+			if(p->from.name == D_AUTO || p->from.name == D_PARAM) {
+				p->from.offset += vreg;
+//				print("%P adjusting from %d %d\n", p, vreg, p->from.type);
+			}
+			if(p->to.sym != S)
+			if(p->to.name == D_AUTO || p->to.name == D_PARAM) {
+				p->to.offset += vreg;
+//				print("%P adjusting to %d %d\n", p, vreg, p->from.type);
+			}
+		}
+	}
+	if(r1 != R) {
+		r1->link = freer;
+		freer = firstr;
+	}
+
+}
+
+void
+addsplits(void)
+{
+	Reg *r, *r1;
+	int z, i;
+	Bits bit;
+
+	for(r = firstr; r != R; r = r->link) {
+		if(r->loop > 1)
+			continue;
+		if(r->prog->as == ABL)
+			continue;
+		for(r1 = r->p2; r1 != R; r1 = r1->p2link) {
+			if(r1->loop <= 1)
+				continue;
+			for(z=0; z<BITS; z++)
+				bit.b[z] = r1->calbehind.b[z] &
+					(r->refahead.b[z] | r->use1.b[z] | r->use2.b[z]) &
+					~(r->calahead.b[z] & addrs.b[z]);
+			while(bany(&bit)) {
+				i = bnum(bit);
+				bit.b[i/32] &= ~(1L << (i%32));
+			}
+		}
+	}
+}
+
+/*
+ * add mov b,rn
+ * just after r
+ */
+void
+addmove(Reg *r, int bn, int rn, int f)
+{
+	Prog *p, *p1, *p2;
+	Adr *a;
+	Var *v;
+
+	p1 = mal(sizeof(*p1));
+	*p1 = zprog;
+	p = r->prog;
+	
+	// If there's a stack fixup coming (after BL newproc or BL deferproc),
+	// delay the load until after the fixup.
+	p2 = p->link;
+	if(p2 && p2->as == AMOVW && p2->from.type == D_CONST && p2->from.reg == REGSP && p2->to.reg == REGSP && p2->to.type == D_REG)
+		p = p2;
+
+	p1->link = p->link;
+	p->link = p1;
+	p1->lineno = p->lineno;
+
+	v = var + bn;
+
+	a = &p1->to;
+	a->sym = v->sym;
+	a->name = v->name;
+	a->node = v->node;
+	a->offset = v->offset;
+	a->etype = v->etype;
+	a->type = D_OREG;
+	if(a->etype == TARRAY || a->sym == S)
+		a->type = D_CONST;
+
+	if(v->addr)
+		fatal("addmove: shouldnt be doing this %A\n", a);
+
+	switch(v->etype) {
+	default:
+		print("What is this %E\n", v->etype);
+
+	case TINT8:
+		p1->as = AMOVB;
+		break;
+	case TBOOL:
+	case TUINT8:
+//print("movbu %E %d %S\n", v->etype, bn, v->sym);
+		p1->as = AMOVBU;
+		break;
+	case TINT16:
+		p1->as = AMOVH;
+		break;
+	case TUINT16:
+		p1->as = AMOVHU;
+		break;
+	case TINT32:
+	case TUINT32:
+	case TPTR32:
+		p1->as = AMOVW;
+		break;
+	case TFLOAT32:
+		p1->as = AMOVF;
+		break;
+	case TFLOAT64:
+		p1->as = AMOVD;
+		break;
+	}
+
+	p1->from.type = D_REG;
+	p1->from.reg = rn;
+	if(rn >= NREG) {
+		p1->from.type = D_FREG;
+		p1->from.reg = rn-NREG;
+	}
+	if(!f) {
+		p1->from = *a;
+		*a = zprog.from;
+		a->type = D_REG;
+		a->reg = rn;
+		if(rn >= NREG) {
+			a->type = D_FREG;
+			a->reg = rn-NREG;
+		}
+		if(v->etype == TUINT8 || v->etype == TBOOL)
+			p1->as = AMOVBU;
+		if(v->etype == TUINT16)
+			p1->as = AMOVHU;
+	}
+	if(debug['R'])
+		print("%P\t.a%P\n", p, p1);
+}
+
+static int
+overlap(int32 o1, int w1, int32 o2, int w2)
+{
+	int32 t1, t2;
+
+	t1 = o1+w1;
+	t2 = o2+w2;
+
+	if(!(t1 > o2 && t2 > o1))
+		return 0;
+
+	return 1;
+}
+
+Bits
+mkvar(Reg *r, Adr *a)
+{
+	Var *v;
+	int i, t, n, et, z, w, flag;
+	int32 o;
+	Bits bit;
+	Sym *s;
+
+	// mark registers used
+	t = a->type;
+	n = D_NONE;
+
+	flag = 0;
+	switch(t) {
+	default:
+		print("type %d %d %D\n", t, a->name, a);
+		goto none;
+
+	case D_NONE:
+	case D_FCONST:
+	case D_BRANCH:
+		break;
+
+	case D_CONST:
+		flag = 1;
+		goto onereg;
+
+	case D_REGREG:
+		bit = zbits;
+		if(a->offset != NREG)
+			bit.b[0] |= RtoB(a->offset);
+		if(a->reg != NREG)
+			bit.b[0] |= RtoB(a->reg);
+		return bit;
+
+	case D_REG:
+	case D_SHIFT:
+	onereg:
+		if(a->reg != NREG) {
+			bit = zbits;
+			bit.b[0] = RtoB(a->reg);
+			return bit;
+		}
+		break;
+
+	case D_OREG:
+		if(a->reg != NREG) {
+			if(a == &r->prog->from)
+				r->use1.b[0] |= RtoB(a->reg);
+			else
+				r->use2.b[0] |= RtoB(a->reg);
+			if(r->prog->scond & (C_PBIT|C_WBIT))
+				r->set.b[0] |= RtoB(a->reg);
+		}
+		break;
+
+	case D_FREG:
+		if(a->reg != NREG) {
+			bit = zbits;
+			bit.b[0] = FtoB(a->reg);
+			return bit;
+		}
+		break;
+	}
+
+	switch(a->name) {
+	default:
+		goto none;
+
+	case D_EXTERN:
+	case D_STATIC:
+	case D_AUTO:
+	case D_PARAM:
+		n = a->name;
+		break;
+	}
+
+	s = a->sym;
+	if(s == S)
+		goto none;
+	if(s->name[0] == '.')
+		goto none;
+	et = a->etype;
+	o = a->offset;
+	w = a->width;
+
+	for(i=0; i<nvar; i++) {
+		v = var+i;
+		if(v->sym == s && v->name == n) {
+			if(v->offset == o)
+			if(v->etype == et)
+			if(v->width == w)
+				if(!flag)
+					return blsh(i);
+
+			// if they overlap, disable both
+			if(overlap(v->offset, v->width, o, w)) {
+				v->addr = 1;
+				flag = 1;
+			}
+		}
+	}
+
+	switch(et) {
+	case 0:
+	case TFUNC:
+	case TARRAY:
+	case TSTRING:
+		goto none;
+	}
+
+	if(nvar >= NVAR) {
+		if(debug['w'] > 1 && s)
+			fatal("variable not optimized: %D", a);
+		goto none;
+	}
+
+	i = nvar;
+	nvar++;
+//print("var %d %E %D %S\n", i, et, a, s);
+	v = var+i;
+	v->sym = s;
+	v->offset = o;
+	v->name = n;
+//	v->gotype = a->gotype;
+	v->etype = et;
+	v->width = w;
+	v->addr = flag;		// funny punning
+	v->node = a->node;
+	
+	if(debug['R'])
+		print("bit=%2d et=%2d w=%d+%d %S %D flag=%d\n", i, et, o, w, s, a, v->addr);
+
+	bit = blsh(i);
+	if(n == D_EXTERN || n == D_STATIC)
+		for(z=0; z<BITS; z++)
+			externs.b[z] |= bit.b[z];
+	if(n == D_PARAM)
+		for(z=0; z<BITS; z++)
+			params.b[z] |= bit.b[z];
+
+	return bit;
+
+none:
+	return zbits;
+}
+
+void
+prop(Reg *r, Bits ref, Bits cal)
+{
+	Reg *r1, *r2;
+	int z;
+
+	for(r1 = r; r1 != R; r1 = r1->p1) {
+		for(z=0; z<BITS; z++) {
+			ref.b[z] |= r1->refahead.b[z];
+			if(ref.b[z] != r1->refahead.b[z]) {
+				r1->refahead.b[z] = ref.b[z];
+				change++;
+			}
+			cal.b[z] |= r1->calahead.b[z];
+			if(cal.b[z] != r1->calahead.b[z]) {
+				r1->calahead.b[z] = cal.b[z];
+				change++;
+			}
+		}
+		switch(r1->prog->as) {
+		case ABL:
+			if(noreturn(r1->prog))
+				break;
+			for(z=0; z<BITS; z++) {
+				cal.b[z] |= ref.b[z] | externs.b[z];
+				ref.b[z] = 0;
+			}
+			break;
+
+		case ATEXT:
+			for(z=0; z<BITS; z++) {
+				cal.b[z] = 0;
+				ref.b[z] = 0;
+			}
+			break;
+
+		case ARET:
+			for(z=0; z<BITS; z++) {
+				cal.b[z] = externs.b[z] | ovar.b[z];
+				ref.b[z] = 0;
+			}
+			break;
+		}
+		for(z=0; z<BITS; z++) {
+			ref.b[z] = (ref.b[z] & ~r1->set.b[z]) |
+				r1->use1.b[z] | r1->use2.b[z];
+			cal.b[z] &= ~(r1->set.b[z] | r1->use1.b[z] | r1->use2.b[z]);
+			r1->refbehind.b[z] = ref.b[z];
+			r1->calbehind.b[z] = cal.b[z];
+		}
+		if(r1->active)
+			break;
+		r1->active = 1;
+	}
+	for(; r != r1; r = r->p1)
+		for(r2 = r->p2; r2 != R; r2 = r2->p2link)
+			prop(r2, r->refbehind, r->calbehind);
+}
+
+/*
+ * find looping structure
+ *
+ * 1) find reverse postordering
+ * 2) find approximate dominators,
+ *	the actual dominators if the flow graph is reducible
+ *	otherwise, dominators plus some other non-dominators.
+ *	See Matthew S. Hecht and Jeffrey D. Ullman,
+ *	"Analysis of a Simple Algorithm for Global Data Flow Problems",
+ *	Conf.  Record of ACM Symp. on Principles of Prog. Langs, Boston, Massachusetts,
+ *	Oct. 1-3, 1973, pp.  207-217.
+ * 3) find all nodes with a predecessor dominated by the current node.
+ *	such a node is a loop head.
+ *	recursively, all preds with a greater rpo number are in the loop
+ */
+int32
+postorder(Reg *r, Reg **rpo2r, int32 n)
+{
+	Reg *r1;
+
+	r->rpo = 1;
+	r1 = r->s1;
+	if(r1 && !r1->rpo)
+		n = postorder(r1, rpo2r, n);
+	r1 = r->s2;
+	if(r1 && !r1->rpo)
+		n = postorder(r1, rpo2r, n);
+	rpo2r[n] = r;
+	n++;
+	return n;
+}
+
+int32
+rpolca(int32 *idom, int32 rpo1, int32 rpo2)
+{
+	int32 t;
+
+	if(rpo1 == -1)
+		return rpo2;
+	while(rpo1 != rpo2){
+		if(rpo1 > rpo2){
+			t = rpo2;
+			rpo2 = rpo1;
+			rpo1 = t;
+		}
+		while(rpo1 < rpo2){
+			t = idom[rpo2];
+			if(t >= rpo2)
+				fatal("bad idom");
+			rpo2 = t;
+		}
+	}
+	return rpo1;
+}
+
+int
+doms(int32 *idom, int32 r, int32 s)
+{
+	while(s > r)
+		s = idom[s];
+	return s == r;
+}
+
+int
+loophead(int32 *idom, Reg *r)
+{
+	int32 src;
+
+	src = r->rpo;
+	if(r->p1 != R && doms(idom, src, r->p1->rpo))
+		return 1;
+	for(r = r->p2; r != R; r = r->p2link)
+		if(doms(idom, src, r->rpo))
+			return 1;
+	return 0;
+}
+
+void
+loopmark(Reg **rpo2r, int32 head, Reg *r)
+{
+	if(r->rpo < head || r->active == head)
+		return;
+	r->active = head;
+	r->loop += LOOP;
+	if(r->p1 != R)
+		loopmark(rpo2r, head, r->p1);
+	for(r = r->p2; r != R; r = r->p2link)
+		loopmark(rpo2r, head, r);
+}
+
+void
+loopit(Reg *r, int32 nr)
+{
+	Reg *r1;
+	int32 i, d, me;
+
+	if(nr > maxnr) {
+		rpo2r = mal(nr * sizeof(Reg*));
+		idom = mal(nr * sizeof(int32));
+		maxnr = nr;
+	}
+	d = postorder(r, rpo2r, 0);
+	if(d > nr)
+		fatal("too many reg nodes");
+	nr = d;
+	for(i = 0; i < nr / 2; i++){
+		r1 = rpo2r[i];
+		rpo2r[i] = rpo2r[nr - 1 - i];
+		rpo2r[nr - 1 - i] = r1;
+	}
+	for(i = 0; i < nr; i++)
+		rpo2r[i]->rpo = i;
+
+	idom[0] = 0;
+	for(i = 0; i < nr; i++){
+		r1 = rpo2r[i];
+		me = r1->rpo;
+		d = -1;
+		if(r1->p1 != R && r1->p1->rpo < me)
+			d = r1->p1->rpo;
+		for(r1 = r1->p2; r1 != nil; r1 = r1->p2link)
+			if(r1->rpo < me)
+				d = rpolca(idom, d, r1->rpo);
+		idom[i] = d;
+	}
+
+	for(i = 0; i < nr; i++){
+		r1 = rpo2r[i];
+		r1->loop++;
+		if(r1->p2 != R && loophead(idom, r1))
+			loopmark(rpo2r, i, r1);
+	}
+}
+
+void
+synch(Reg *r, Bits dif)
+{
+	Reg *r1;
+	int z;
+
+	for(r1 = r; r1 != R; r1 = r1->s1) {
+		for(z=0; z<BITS; z++) {
+			dif.b[z] = (dif.b[z] &
+				~(~r1->refbehind.b[z] & r1->refahead.b[z])) |
+					r1->set.b[z] | r1->regdiff.b[z];
+			if(dif.b[z] != r1->regdiff.b[z]) {
+				r1->regdiff.b[z] = dif.b[z];
+				change++;
+			}
+		}
+		if(r1->active)
+			break;
+		r1->active = 1;
+		for(z=0; z<BITS; z++)
+			dif.b[z] &= ~(~r1->calbehind.b[z] & r1->calahead.b[z]);
+		if(r1->s2 != R)
+			synch(r1->s2, dif);
+	}
+}
+
+uint32
+allreg(uint32 b, Rgn *r)
+{
+	Var *v;
+	int i;
+
+	v = var + r->varno;
+	r->regno = 0;
+	switch(v->etype) {
+
+	default:
+		fatal("unknown etype %d/%E", bitno(b), v->etype);
+		break;
+
+	case TINT8:
+	case TUINT8:
+	case TINT16:
+	case TUINT16:
+	case TINT32:
+	case TUINT32:
+	case TINT:
+	case TUINT:
+	case TUINTPTR:
+	case TBOOL:
+	case TPTR32:
+		i = BtoR(~b);
+		if(i && r->cost >= 0) {
+			r->regno = i;
+			return RtoB(i);
+		}
+		break;
+
+	case TFLOAT32:
+	case TFLOAT64:
+		i = BtoF(~b);
+		if(i && r->cost >= 0) {
+			r->regno = i+NREG;
+			return FtoB(i);
+		}
+		break;
+
+	case TINT64:
+	case TUINT64:
+	case TPTR64:
+	case TINTER:
+	case TSTRUCT:
+	case TARRAY:
+		break;
+	}
+	return 0;
+}
+
+void
+paint1(Reg *r, int bn)
+{
+	Reg *r1;
+	Prog *p;
+	int z;
+	uint32 bb;
+
+	z = bn/32;
+	bb = 1L<<(bn%32);
+	if(r->act.b[z] & bb)
+		return;
+	for(;;) {
+		if(!(r->refbehind.b[z] & bb))
+			break;
+		r1 = r->p1;
+		if(r1 == R)
+			break;
+		if(!(r1->refahead.b[z] & bb))
+			break;
+		if(r1->act.b[z] & bb)
+			break;
+		r = r1;
+	}
+
+	if(LOAD(r) & ~(r->set.b[z] & ~(r->use1.b[z]|r->use2.b[z])) & bb) {
+		change -= CLOAD * r->loop;
+		if(debug['R'] > 1)
+			print("%d%P\td %Q $%d\n", r->loop,
+				r->prog, blsh(bn), change);
+	}
+	for(;;) {
+		r->act.b[z] |= bb;
+		p = r->prog;
+
+		if(r->use1.b[z] & bb) {
+			change += CREF * r->loop;
+			if(debug['R'] > 1)
+				print("%d%P\tu1 %Q $%d\n", r->loop,
+					p, blsh(bn), change);
+		}
+
+		if((r->use2.b[z]|r->set.b[z]) & bb) {
+			change += CREF * r->loop;
+			if(debug['R'] > 1)
+				print("%d%P\tu2 %Q $%d\n", r->loop,
+					p, blsh(bn), change);
+		}
+
+		if(STORE(r) & r->regdiff.b[z] & bb) {
+			change -= CLOAD * r->loop;
+			if(debug['R'] > 1)
+				print("%d%P\tst %Q $%d\n", r->loop,
+					p, blsh(bn), change);
+		}
+
+		if(r->refbehind.b[z] & bb)
+			for(r1 = r->p2; r1 != R; r1 = r1->p2link)
+				if(r1->refahead.b[z] & bb)
+					paint1(r1, bn);
+
+		if(!(r->refahead.b[z] & bb))
+			break;
+		r1 = r->s2;
+		if(r1 != R)
+			if(r1->refbehind.b[z] & bb)
+				paint1(r1, bn);
+		r = r->s1;
+		if(r == R)
+			break;
+		if(r->act.b[z] & bb)
+			break;
+		if(!(r->refbehind.b[z] & bb))
+			break;
+	}
+}
+
+uint32
+paint2(Reg *r, int bn)
+{
+	Reg *r1;
+	int z;
+	uint32 bb, vreg;
+
+	z = bn/32;
+	bb = 1L << (bn%32);
+	vreg = regbits;
+	if(!(r->act.b[z] & bb))
+		return vreg;
+	for(;;) {
+		if(!(r->refbehind.b[z] & bb))
+			break;
+		r1 = r->p1;
+		if(r1 == R)
+			break;
+		if(!(r1->refahead.b[z] & bb))
+			break;
+		if(!(r1->act.b[z] & bb))
+			break;
+		r = r1;
+	}
+	for(;;) {
+		r->act.b[z] &= ~bb;
+
+		vreg |= r->regu;
+
+		if(r->refbehind.b[z] & bb)
+			for(r1 = r->p2; r1 != R; r1 = r1->p2link)
+				if(r1->refahead.b[z] & bb)
+					vreg |= paint2(r1, bn);
+
+		if(!(r->refahead.b[z] & bb))
+			break;
+		r1 = r->s2;
+		if(r1 != R)
+			if(r1->refbehind.b[z] & bb)
+				vreg |= paint2(r1, bn);
+		r = r->s1;
+		if(r == R)
+			break;
+		if(!(r->act.b[z] & bb))
+			break;
+		if(!(r->refbehind.b[z] & bb))
+			break;
+	}
+	return vreg;
+}
+
+void
+paint3(Reg *r, int bn, int32 rb, int rn)
+{
+	Reg *r1;
+	Prog *p;
+	int z;
+	uint32 bb;
+
+	z = bn/32;
+	bb = 1L << (bn%32);
+	if(r->act.b[z] & bb)
+		return;
+	for(;;) {
+		if(!(r->refbehind.b[z] & bb))
+			break;
+		r1 = r->p1;
+		if(r1 == R)
+			break;
+		if(!(r1->refahead.b[z] & bb))
+			break;
+		if(r1->act.b[z] & bb)
+			break;
+		r = r1;
+	}
+
+	if(LOAD(r) & ~(r->set.b[z] & ~(r->use1.b[z]|r->use2.b[z])) & bb)
+		addmove(r, bn, rn, 0);
+
+	for(;;) {
+		r->act.b[z] |= bb;
+		p = r->prog;
+
+		if(r->use1.b[z] & bb) {
+			if(debug['R'])
+				print("%P", p);
+			addreg(&p->from, rn);
+			if(debug['R'])
+				print("\t.c%P\n", p);
+		}
+		if((r->use2.b[z]|r->set.b[z]) & bb) {
+			if(debug['R'])
+				print("%P", p);
+			addreg(&p->to, rn);
+			if(debug['R'])
+				print("\t.c%P\n", p);
+		}
+
+		if(STORE(r) & r->regdiff.b[z] & bb)
+			addmove(r, bn, rn, 1);
+		r->regu |= rb;
+
+		if(r->refbehind.b[z] & bb)
+			for(r1 = r->p2; r1 != R; r1 = r1->p2link)
+				if(r1->refahead.b[z] & bb)
+					paint3(r1, bn, rb, rn);
+
+		if(!(r->refahead.b[z] & bb))
+			break;
+		r1 = r->s2;
+		if(r1 != R)
+			if(r1->refbehind.b[z] & bb)
+				paint3(r1, bn, rb, rn);
+		r = r->s1;
+		if(r == R)
+			break;
+		if(r->act.b[z] & bb)
+			break;
+		if(!(r->refbehind.b[z] & bb))
+			break;
+	}
+}
+
+void
+addreg(Adr *a, int rn)
+{
+	a->sym = 0;
+	a->name = D_NONE;
+	a->type = D_REG;
+	a->reg = rn;
+	if(rn >= NREG) {
+		a->type = D_FREG;
+		a->reg = rn-NREG;
+	}
+}
+
+/*
+ *	bit	reg
+ *	0	R0
+ *	1	R1
+ *	...	...
+ *	10	R10
+ */
+int32
+RtoB(int r)
+{
+	if(r >= REGTMP-2)	// excluded R9 and R10 for m and g
+		return 0;
+	return 1L << r;
+}
+
+int
+BtoR(int32 b)
+{
+	b &= 0x01fcL;	// excluded R9 and R10 for m and g
+	if(b == 0)
+		return 0;
+	return bitno(b);
+}
+
+/*
+ *	bit	reg
+ *	18	F2
+ *	19	F3
+ *	...	...
+ *	23	F7
+ */
+int32
+FtoB(int f)
+{
+
+	if(f < 2 || f > NFREG-1)
+		return 0;
+	return 1L << (f + 16);
+}
+
+int
+BtoF(int32 b)
+{
+
+	b &= 0xfc0000L;
+	if(b == 0)
+		return 0;
+	return bitno(b) - 16;
+}
+
+static Sym*	symlist[10];
+
+int
+noreturn(Prog *p)
+{
+	Sym *s;
+	int i;
+
+	if(symlist[0] == S) {
+		symlist[0] = pkglookup("panicindex", runtimepkg);
+		symlist[1] = pkglookup("panicslice", runtimepkg);
+		symlist[2] = pkglookup("throwinit", runtimepkg);
+		symlist[3] = pkglookup("panic", runtimepkg);
+		symlist[4] = pkglookup("panicwrap", runtimepkg);
+	}
+
+	s = p->to.sym;
+	if(s == S)
+		return 0;
+	for(i=0; symlist[i]!=S; i++)
+		if(s == symlist[i])
+			return 1;
+	return 0;
+}
+
+void
+dumpone(Reg *r)
+{
+	int z;
+	Bits bit;
+
+	print("%d:%P", r->loop, r->prog);
+	for(z=0; z<BITS; z++)
+		bit.b[z] =
+			r->set.b[z] |
+			r->use1.b[z] |
+			r->use2.b[z] |
+			r->refbehind.b[z] |
+			r->refahead.b[z] |
+			r->calbehind.b[z] |
+			r->calahead.b[z] |
+			r->regdiff.b[z] |
+			r->act.b[z] |
+				0;
+	if(bany(&bit)) {
+		print("\t");
+		if(bany(&r->set))
+			print(" s:%Q", r->set);
+		if(bany(&r->use1))
+			print(" u1:%Q", r->use1);
+		if(bany(&r->use2))
+			print(" u2:%Q", r->use2);
+		if(bany(&r->refbehind))
+			print(" rb:%Q ", r->refbehind);
+		if(bany(&r->refahead))
+			print(" ra:%Q ", r->refahead);
+		if(bany(&r->calbehind))
+			print("cb:%Q ", r->calbehind);
+		if(bany(&r->calahead))
+			print(" ca:%Q ", r->calahead);
+		if(bany(&r->regdiff))
+			print(" d:%Q ", r->regdiff);
+		if(bany(&r->act))
+			print(" a:%Q ", r->act);
+	}
+	print("\n");
+}
+
+void
+dumpit(char *str, Reg *r0)
+{
+	Reg *r, *r1;
+
+	print("\n%s\n", str);
+	for(r = r0; r != R; r = r->link) {
+		dumpone(r);
+		r1 = r->p2;
+		if(r1 != R) {
+			print("	pred:");
+			for(; r1 != R; r1 = r1->p2link)
+				print(" %.4ud", r1->prog->loc);
+			print("\n");
+		}
+//		r1 = r->s1;
+//		if(r1 != R) {
+//			print("	succ:");
+//			for(; r1 != R; r1 = r1->s1)
+//				print(" %.4ud", r1->prog->loc);
+//			print("\n");
+//		}
+	}
+}