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-rw-r--r--src/runtime/softfloat_arm.c687
1 files changed, 687 insertions, 0 deletions
diff --git a/src/runtime/softfloat_arm.c b/src/runtime/softfloat_arm.c
new file mode 100644
index 000000000..3f3f33a19
--- /dev/null
+++ b/src/runtime/softfloat_arm.c
@@ -0,0 +1,687 @@
+// 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.
+
+// Software floating point interpretaton of ARM 7500 FP instructions.
+// The interpretation is not bit compatible with the 7500.
+// It uses true little-endian doubles, while the 7500 used mixed-endian.
+
+#include "runtime.h"
+#include "textflag.h"
+
+#define CPSR 14
+#define FLAGS_N (1U << 31)
+#define FLAGS_Z (1U << 30)
+#define FLAGS_C (1U << 29)
+#define FLAGS_V (1U << 28)
+
+void runtime·abort(void);
+void runtime·sqrtC(uint64, uint64*);
+
+static uint32 trace = 0;
+
+static void
+fabort(void)
+{
+ if (1) {
+ runtime·printf("Unsupported floating point instruction\n");
+ runtime·abort();
+ }
+}
+
+static void
+putf(uint32 reg, uint32 val)
+{
+ g->m->freglo[reg] = val;
+}
+
+static void
+putd(uint32 reg, uint64 val)
+{
+ g->m->freglo[reg] = (uint32)val;
+ g->m->freghi[reg] = (uint32)(val>>32);
+}
+
+static uint64
+getd(uint32 reg)
+{
+ return (uint64)g->m->freglo[reg] | ((uint64)g->m->freghi[reg]<<32);
+}
+
+static void
+fprint(void)
+{
+ uint32 i;
+ for (i = 0; i < 16; i++) {
+ runtime·printf("\tf%d:\t%X %X\n", i, g->m->freghi[i], g->m->freglo[i]);
+ }
+}
+
+static uint32
+d2f(uint64 d)
+{
+ uint32 x;
+
+ runtime·f64to32c(d, &x);
+ return x;
+}
+
+static uint64
+f2d(uint32 f)
+{
+ uint64 x;
+
+ runtime·f32to64c(f, &x);
+ return x;
+}
+
+static uint32
+fstatus(bool nan, int32 cmp)
+{
+ if(nan)
+ return FLAGS_C | FLAGS_V;
+ if(cmp == 0)
+ return FLAGS_Z | FLAGS_C;
+ if(cmp < 0)
+ return FLAGS_N;
+ return FLAGS_C;
+}
+
+// conditions array record the required CPSR cond field for the
+// first 5 pairs of conditional execution opcodes
+// higher 4 bits are must set, lower 4 bits are must clear
+#pragma dataflag NOPTR
+static const uint8 conditions[10/2] = {
+ [0/2] = (FLAGS_Z >> 24) | 0, // 0: EQ (Z set), 1: NE (Z clear)
+ [2/2] = (FLAGS_C >> 24) | 0, // 2: CS/HS (C set), 3: CC/LO (C clear)
+ [4/2] = (FLAGS_N >> 24) | 0, // 4: MI (N set), 5: PL (N clear)
+ [6/2] = (FLAGS_V >> 24) | 0, // 6: VS (V set), 7: VC (V clear)
+ [8/2] = (FLAGS_C >> 24) |
+ (FLAGS_Z >> 28), // 8: HI (C set and Z clear), 9: LS (C clear and Z set)
+};
+
+#define FAULT (0x80000000U) // impossible PC offset
+
+// returns number of words that the fp instruction
+// is occupying, 0 if next instruction isn't float.
+static uint32
+stepflt(uint32 *pc, uint32 *regs)
+{
+ uint32 i, opc, regd, regm, regn, cpsr;
+ int32 delta;
+ uint32 *addr;
+ uint64 uval;
+ int64 sval;
+ bool nan, ok;
+ int32 cmp;
+ M *m;
+
+ // m is locked in vlop_arm.s, so g->m cannot change during this function call,
+ // so caching it in a local variable is safe.
+ m = g->m;
+ i = *pc;
+
+ if(trace)
+ runtime·printf("stepflt %p %x (cpsr %x)\n", pc, i, regs[CPSR] >> 28);
+
+ opc = i >> 28;
+ if(opc == 14) // common case first
+ goto execute;
+ cpsr = regs[CPSR] >> 28;
+ switch(opc) {
+ case 0: case 1: case 2: case 3: case 4:
+ case 5: case 6: case 7: case 8: case 9:
+ if(((cpsr & (conditions[opc/2] >> 4)) == (conditions[opc/2] >> 4)) &&
+ ((cpsr & (conditions[opc/2] & 0xf)) == 0)) {
+ if(opc & 1) return 1;
+ } else {
+ if(!(opc & 1)) return 1;
+ }
+ break;
+ case 10: // GE (N == V)
+ case 11: // LT (N != V)
+ if((cpsr & (FLAGS_N >> 28)) == (cpsr & (FLAGS_V >> 28))) {
+ if(opc & 1) return 1;
+ } else {
+ if(!(opc & 1)) return 1;
+ }
+ break;
+ case 12: // GT (N == V and Z == 0)
+ case 13: // LE (N != V or Z == 1)
+ if((cpsr & (FLAGS_N >> 28)) == (cpsr & (FLAGS_V >> 28)) &&
+ (cpsr & (FLAGS_Z >> 28)) == 0) {
+ if(opc & 1) return 1;
+ } else {
+ if(!(opc & 1)) return 1;
+ }
+ break;
+ case 14: // AL
+ break;
+ case 15: // shouldn't happen
+ return 0;
+ }
+ if(trace)
+ runtime·printf("conditional %x (cpsr %x) pass\n", opc, cpsr);
+ i = (0xeU << 28) | (i & 0xfffffff);
+
+execute:
+ // special cases
+ if((i&0xfffff000) == 0xe59fb000) {
+ // load r11 from pc-relative address.
+ // might be part of a floating point move
+ // (or might not, but no harm in simulating
+ // one instruction too many).
+ addr = (uint32*)((uint8*)pc + (i&0xfff) + 8);
+ regs[11] = addr[0];
+
+ if(trace)
+ runtime·printf("*** cpu R[%d] = *(%p) %x\n",
+ 11, addr, regs[11]);
+ return 1;
+ }
+ if(i == 0xe08bb00d) {
+ // add sp to r11.
+ // might be part of a large stack offset address
+ // (or might not, but again no harm done).
+ regs[11] += regs[13];
+
+ if(trace)
+ runtime·printf("*** cpu R[%d] += R[%d] %x\n",
+ 11, 13, regs[11]);
+ return 1;
+ }
+ if(i == 0xeef1fa10) {
+ regs[CPSR] = (regs[CPSR]&0x0fffffff) | m->fflag;
+
+ if(trace)
+ runtime·printf("*** fpsr R[CPSR] = F[CPSR] %x\n", regs[CPSR]);
+ return 1;
+ }
+ if((i&0xff000000) == 0xea000000) {
+ // unconditional branch
+ // can happen in the middle of floating point
+ // if the linker decides it is time to lay down
+ // a sequence of instruction stream constants.
+ delta = i&0xffffff;
+ delta = (delta<<8) >> 8; // sign extend
+
+ if(trace)
+ runtime·printf("*** cpu PC += %x\n", (delta+2)*4);
+ return delta+2;
+ }
+
+ goto stage1;
+
+stage1: // load/store regn is cpureg, regm is 8bit offset
+ regd = i>>12 & 0xf;
+ regn = i>>16 & 0xf;
+ regm = (i & 0xff) << 2; // PLUS or MINUS ??
+
+ switch(i & 0xfff00f00) {
+ default:
+ goto stage2;
+
+ case 0xed900a00: // single load
+ addr = (uint32*)(regs[regn] + regm);
+ if((uintptr)addr < 4096) {
+ if(trace)
+ runtime·printf("*** load @%p => fault\n", addr);
+ return FAULT;
+ }
+ m->freglo[regd] = addr[0];
+
+ if(trace)
+ runtime·printf("*** load F[%d] = %x\n",
+ regd, m->freglo[regd]);
+ break;
+
+ case 0xed900b00: // double load
+ addr = (uint32*)(regs[regn] + regm);
+ if((uintptr)addr < 4096) {
+ if(trace)
+ runtime·printf("*** double load @%p => fault\n", addr);
+ return FAULT;
+ }
+ m->freglo[regd] = addr[0];
+ m->freghi[regd] = addr[1];
+
+ if(trace)
+ runtime·printf("*** load D[%d] = %x-%x\n",
+ regd, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xed800a00: // single store
+ addr = (uint32*)(regs[regn] + regm);
+ if((uintptr)addr < 4096) {
+ if(trace)
+ runtime·printf("*** store @%p => fault\n", addr);
+ return FAULT;
+ }
+ addr[0] = m->freglo[regd];
+
+ if(trace)
+ runtime·printf("*** *(%p) = %x\n",
+ addr, addr[0]);
+ break;
+
+ case 0xed800b00: // double store
+ addr = (uint32*)(regs[regn] + regm);
+ if((uintptr)addr < 4096) {
+ if(trace)
+ runtime·printf("*** double store @%p => fault\n", addr);
+ return FAULT;
+ }
+ addr[0] = m->freglo[regd];
+ addr[1] = m->freghi[regd];
+
+ if(trace)
+ runtime·printf("*** *(%p) = %x-%x\n",
+ addr, addr[1], addr[0]);
+ break;
+ }
+ return 1;
+
+stage2: // regd, regm, regn are 4bit variables
+ regm = i>>0 & 0xf;
+ switch(i & 0xfff00ff0) {
+ default:
+ goto stage3;
+
+ case 0xf3000110: // veor
+ m->freglo[regd] = m->freglo[regm]^m->freglo[regn];
+ m->freghi[regd] = m->freghi[regm]^m->freghi[regn];
+
+ if(trace)
+ runtime·printf("*** veor D[%d] = %x-%x\n",
+ regd, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeeb00b00: // D[regd] = const(regn,regm)
+ regn = (regn<<4) | regm;
+ regm = 0x40000000UL;
+ if(regn & 0x80)
+ regm |= 0x80000000UL;
+ if(regn & 0x40)
+ regm ^= 0x7fc00000UL;
+ regm |= (regn & 0x3f) << 16;
+ m->freglo[regd] = 0;
+ m->freghi[regd] = regm;
+
+ if(trace)
+ runtime·printf("*** immed D[%d] = %x-%x\n",
+ regd, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeeb00a00: // F[regd] = const(regn,regm)
+ regn = (regn<<4) | regm;
+ regm = 0x40000000UL;
+ if(regn & 0x80)
+ regm |= 0x80000000UL;
+ if(regn & 0x40)
+ regm ^= 0x7e000000UL;
+ regm |= (regn & 0x3f) << 19;
+ m->freglo[regd] = regm;
+
+ if(trace)
+ runtime·printf("*** immed D[%d] = %x\n",
+ regd, m->freglo[regd]);
+ break;
+
+ case 0xee300b00: // D[regd] = D[regn]+D[regm]
+ runtime·fadd64c(getd(regn), getd(regm), &uval);
+ putd(regd, uval);
+
+ if(trace)
+ runtime·printf("*** add D[%d] = D[%d]+D[%d] %x-%x\n",
+ regd, regn, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xee300a00: // F[regd] = F[regn]+F[regm]
+ runtime·fadd64c(f2d(m->freglo[regn]), f2d(m->freglo[regm]), &uval);
+ m->freglo[regd] = d2f(uval);
+
+ if(trace)
+ runtime·printf("*** add F[%d] = F[%d]+F[%d] %x\n",
+ regd, regn, regm, m->freglo[regd]);
+ break;
+
+ case 0xee300b40: // D[regd] = D[regn]-D[regm]
+ runtime·fsub64c(getd(regn), getd(regm), &uval);
+ putd(regd, uval);
+
+ if(trace)
+ runtime·printf("*** sub D[%d] = D[%d]-D[%d] %x-%x\n",
+ regd, regn, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xee300a40: // F[regd] = F[regn]-F[regm]
+ runtime·fsub64c(f2d(m->freglo[regn]), f2d(m->freglo[regm]), &uval);
+ m->freglo[regd] = d2f(uval);
+
+ if(trace)
+ runtime·printf("*** sub F[%d] = F[%d]-F[%d] %x\n",
+ regd, regn, regm, m->freglo[regd]);
+ break;
+
+ case 0xee200b00: // D[regd] = D[regn]*D[regm]
+ runtime·fmul64c(getd(regn), getd(regm), &uval);
+ putd(regd, uval);
+
+ if(trace)
+ runtime·printf("*** mul D[%d] = D[%d]*D[%d] %x-%x\n",
+ regd, regn, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xee200a00: // F[regd] = F[regn]*F[regm]
+ runtime·fmul64c(f2d(m->freglo[regn]), f2d(m->freglo[regm]), &uval);
+ m->freglo[regd] = d2f(uval);
+
+ if(trace)
+ runtime·printf("*** mul F[%d] = F[%d]*F[%d] %x\n",
+ regd, regn, regm, m->freglo[regd]);
+ break;
+
+ case 0xee800b00: // D[regd] = D[regn]/D[regm]
+ runtime·fdiv64c(getd(regn), getd(regm), &uval);
+ putd(regd, uval);
+
+ if(trace)
+ runtime·printf("*** div D[%d] = D[%d]/D[%d] %x-%x\n",
+ regd, regn, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xee800a00: // F[regd] = F[regn]/F[regm]
+ runtime·fdiv64c(f2d(m->freglo[regn]), f2d(m->freglo[regm]), &uval);
+ m->freglo[regd] = d2f(uval);
+
+ if(trace)
+ runtime·printf("*** div F[%d] = F[%d]/F[%d] %x\n",
+ regd, regn, regm, m->freglo[regd]);
+ break;
+
+ case 0xee000b10: // S[regn] = R[regd] (MOVW) (regm ignored)
+ m->freglo[regn] = regs[regd];
+
+ if(trace)
+ runtime·printf("*** cpy S[%d] = R[%d] %x\n",
+ regn, regd, m->freglo[regn]);
+ break;
+
+ case 0xee100b10: // R[regd] = S[regn] (MOVW) (regm ignored)
+ regs[regd] = m->freglo[regn];
+
+ if(trace)
+ runtime·printf("*** cpy R[%d] = S[%d] %x\n",
+ regd, regn, regs[regd]);
+ break;
+ }
+ return 1;
+
+stage3: // regd, regm are 4bit variables
+ switch(i & 0xffff0ff0) {
+ default:
+ goto done;
+
+ case 0xeeb00a40: // F[regd] = F[regm] (MOVF)
+ m->freglo[regd] = m->freglo[regm];
+
+ if(trace)
+ runtime·printf("*** F[%d] = F[%d] %x\n",
+ regd, regm, m->freglo[regd]);
+ break;
+
+ case 0xeeb00b40: // D[regd] = D[regm] (MOVD)
+ m->freglo[regd] = m->freglo[regm];
+ m->freghi[regd] = m->freghi[regm];
+
+ if(trace)
+ runtime·printf("*** D[%d] = D[%d] %x-%x\n",
+ regd, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeeb10bc0: // D[regd] = sqrt D[regm]
+ runtime·sqrtC(getd(regm), &uval);
+ putd(regd, uval);
+
+ if(trace)
+ runtime·printf("*** D[%d] = sqrt D[%d] %x-%x\n",
+ regd, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeeb00bc0: // D[regd] = abs D[regm]
+ m->freglo[regd] = m->freglo[regm];
+ m->freghi[regd] = m->freghi[regm] & ((1<<31)-1);
+
+ if(trace)
+ runtime·printf("*** D[%d] = abs D[%d] %x-%x\n",
+ regd, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeeb00ac0: // F[regd] = abs F[regm]
+ m->freglo[regd] = m->freglo[regm] & ((1<<31)-1);
+
+ if(trace)
+ runtime·printf("*** F[%d] = abs F[%d] %x\n",
+ regd, regm, m->freglo[regd]);
+ break;
+
+ case 0xeeb40bc0: // D[regd] :: D[regm] (CMPD)
+ runtime·fcmp64c(getd(regd), getd(regm), &cmp, &nan);
+ m->fflag = fstatus(nan, cmp);
+
+ if(trace)
+ runtime·printf("*** cmp D[%d]::D[%d] %x\n",
+ regd, regm, m->fflag);
+ break;
+
+ case 0xeeb40ac0: // F[regd] :: F[regm] (CMPF)
+ runtime·fcmp64c(f2d(m->freglo[regd]), f2d(m->freglo[regm]), &cmp, &nan);
+ m->fflag = fstatus(nan, cmp);
+
+ if(trace)
+ runtime·printf("*** cmp F[%d]::F[%d] %x\n",
+ regd, regm, m->fflag);
+ break;
+
+ case 0xeeb70ac0: // D[regd] = F[regm] (MOVFD)
+ putd(regd, f2d(m->freglo[regm]));
+
+ if(trace)
+ runtime·printf("*** f2d D[%d]=F[%d] %x-%x\n",
+ regd, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeeb70bc0: // F[regd] = D[regm] (MOVDF)
+ m->freglo[regd] = d2f(getd(regm));
+
+ if(trace)
+ runtime·printf("*** d2f F[%d]=D[%d] %x-%x\n",
+ regd, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeebd0ac0: // S[regd] = F[regm] (MOVFW)
+ runtime·f64tointc(f2d(m->freglo[regm]), &sval, &ok);
+ if(!ok || (int32)sval != sval)
+ sval = 0;
+ m->freglo[regd] = sval;
+
+ if(trace)
+ runtime·printf("*** fix S[%d]=F[%d] %x\n",
+ regd, regm, m->freglo[regd]);
+ break;
+
+ case 0xeebc0ac0: // S[regd] = F[regm] (MOVFW.U)
+ runtime·f64tointc(f2d(m->freglo[regm]), &sval, &ok);
+ if(!ok || (uint32)sval != sval)
+ sval = 0;
+ m->freglo[regd] = sval;
+
+ if(trace)
+ runtime·printf("*** fix unsigned S[%d]=F[%d] %x\n",
+ regd, regm, m->freglo[regd]);
+ break;
+
+ case 0xeebd0bc0: // S[regd] = D[regm] (MOVDW)
+ runtime·f64tointc(getd(regm), &sval, &ok);
+ if(!ok || (int32)sval != sval)
+ sval = 0;
+ m->freglo[regd] = sval;
+
+ if(trace)
+ runtime·printf("*** fix S[%d]=D[%d] %x\n",
+ regd, regm, m->freglo[regd]);
+ break;
+
+ case 0xeebc0bc0: // S[regd] = D[regm] (MOVDW.U)
+ runtime·f64tointc(getd(regm), &sval, &ok);
+ if(!ok || (uint32)sval != sval)
+ sval = 0;
+ m->freglo[regd] = sval;
+
+ if(trace)
+ runtime·printf("*** fix unsigned S[%d]=D[%d] %x\n",
+ regd, regm, m->freglo[regd]);
+ break;
+
+ case 0xeeb80ac0: // D[regd] = S[regm] (MOVWF)
+ cmp = m->freglo[regm];
+ if(cmp < 0) {
+ runtime·fintto64c(-cmp, &uval);
+ putf(regd, d2f(uval));
+ m->freglo[regd] ^= 0x80000000;
+ } else {
+ runtime·fintto64c(cmp, &uval);
+ putf(regd, d2f(uval));
+ }
+
+ if(trace)
+ runtime·printf("*** float D[%d]=S[%d] %x-%x\n",
+ regd, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeeb80a40: // D[regd] = S[regm] (MOVWF.U)
+ runtime·fintto64c(m->freglo[regm], &uval);
+ putf(regd, d2f(uval));
+
+ if(trace)
+ runtime·printf("*** float unsigned D[%d]=S[%d] %x-%x\n",
+ regd, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeeb80bc0: // D[regd] = S[regm] (MOVWD)
+ cmp = m->freglo[regm];
+ if(cmp < 0) {
+ runtime·fintto64c(-cmp, &uval);
+ putd(regd, uval);
+ m->freghi[regd] ^= 0x80000000;
+ } else {
+ runtime·fintto64c(cmp, &uval);
+ putd(regd, uval);
+ }
+
+ if(trace)
+ runtime·printf("*** float D[%d]=S[%d] %x-%x\n",
+ regd, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+
+ case 0xeeb80b40: // D[regd] = S[regm] (MOVWD.U)
+ runtime·fintto64c(m->freglo[regm], &uval);
+ putd(regd, uval);
+
+ if(trace)
+ runtime·printf("*** float unsigned D[%d]=S[%d] %x-%x\n",
+ regd, regm, m->freghi[regd], m->freglo[regd]);
+ break;
+ }
+ return 1;
+
+done:
+ if((i&0xff000000) == 0xee000000 ||
+ (i&0xff000000) == 0xed000000) {
+ runtime·printf("stepflt %p %x\n", pc, i);
+ fabort();
+ }
+ return 0;
+}
+
+typedef struct Sfregs Sfregs;
+
+// NOTE: These are all recorded as pointers because they are possibly live registers,
+// and we don't know what they contain. Recording them as pointers should be
+// safer than not.
+struct Sfregs
+{
+ uint32 *r0;
+ uint32 *r1;
+ uint32 *r2;
+ uint32 *r3;
+ uint32 *r4;
+ uint32 *r5;
+ uint32 *r6;
+ uint32 *r7;
+ uint32 *r8;
+ uint32 *r9;
+ uint32 *r10;
+ uint32 *r11;
+ uint32 *r12;
+ uint32 *r13;
+ uint32 cspr;
+};
+
+static void sfloat2(void);
+void _sfloatpanic(void);
+
+#pragma textflag NOSPLIT
+uint32*
+runtime·_sfloat2(uint32 *pc, Sfregs regs)
+{
+ void (*fn)(void);
+
+ g->m->ptrarg[0] = pc;
+ g->m->ptrarg[1] = &regs;
+ fn = sfloat2;
+ runtime·onM(&fn);
+ pc = g->m->ptrarg[0];
+ g->m->ptrarg[0] = nil;
+ return pc;
+}
+
+static void
+sfloat2(void)
+{
+ uint32 *pc;
+ G *curg;
+ Sfregs *regs;
+ int32 skip;
+ bool first;
+
+ pc = g->m->ptrarg[0];
+ regs = g->m->ptrarg[1];
+ g->m->ptrarg[0] = nil;
+ g->m->ptrarg[1] = nil;
+
+ first = true;
+ while(skip = stepflt(pc, (uint32*)&regs->r0)) {
+ first = false;
+ if(skip == FAULT) {
+ // Encountered bad address in store/load.
+ // Record signal information and return to assembly
+ // trampoline that fakes the call.
+ enum { SIGSEGV = 11 };
+ curg = g->m->curg;
+ curg->sig = SIGSEGV;
+ curg->sigcode0 = 0;
+ curg->sigcode1 = 0;
+ curg->sigpc = (uint32)pc;
+ pc = (uint32*)_sfloatpanic;
+ break;
+ }
+ pc += skip;
+ }
+ if(first) {
+ runtime·printf("sfloat2 %p %x\n", pc, *pc);
+ fabort(); // not ok to fail first instruction
+ }
+
+ g->m->ptrarg[0] = pc;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-17 21:18:39 +0000