diff options
Diffstat (limited to 'src/cmd/8g/ggen.c')
| -rw-r--r-- | src/cmd/8g/ggen.c | 96 |
1 files changed, 81 insertions, 15 deletions
diff --git a/src/cmd/8g/ggen.c b/src/cmd/8g/ggen.c index 6db0474c9..108c493aa 100644 --- a/src/cmd/8g/ggen.c +++ b/src/cmd/8g/ggen.c @@ -480,12 +480,40 @@ samereg(Node *a, Node *b) * according to op. */ void -dodiv(int op, Type *t, Node *nl, Node *nr, Node *res, Node *ax, Node *dx) +dodiv(int op, Node *nl, Node *nr, Node *res, Node *ax, Node *dx) { - Node n1, t1, t2, nz; + int check; + Node n1, t1, t2, n4, nz; + Type *t; + Prog *p1, *p2, *p3; + + // Have to be careful about handling + // most negative int divided by -1 correctly. + // The hardware will trap. + // Also the byte divide instruction needs AH, + // which we otherwise don't have to deal with. + // Easiest way to avoid for int8, int16: use int32. + // For int32 and int64, use explicit test. + // Could use int64 hw for int32. + t = nl->type; + check = 0; + if(issigned[t->etype]) { + check = 1; + if(isconst(nl, CTINT) && mpgetfix(nl->val.u.xval) != -1LL<<(t->width*8-1)) + check = 0; + else if(isconst(nr, CTINT) && mpgetfix(nr->val.u.xval) != -1) + check = 0; + } + if(t->width < 4) { + if(issigned[t->etype]) + t = types[TINT32]; + else + t = types[TUINT32]; + check = 0; + } - tempname(&t1, nl->type); - tempname(&t2, nr->type); + tempname(&t1, t); + tempname(&t2, t); cgen(nl, &t1); cgen(nr, &t2); @@ -495,6 +523,24 @@ dodiv(int op, Type *t, Node *nl, Node *nr, Node *res, Node *ax, Node *dx) regalloc(&n1, t, N); gmove(&t2, &n1); gmove(&t1, ax); + p3 = P; + if(check) { + nodconst(&n4, t, -1); + gins(optoas(OCMP, t), &n1, &n4); + p1 = gbranch(optoas(ONE, t), T); + nodconst(&n4, t, -1LL<<(t->width*8-1)); + gins(optoas(OCMP, t), ax, &n4); + p2 = gbranch(optoas(ONE, t), T); + if(op == ODIV) + gmove(&n4, res); + if(op == OMOD) { + nodconst(&n4, t, 0); + gmove(&n4, res); + } + p3 = gbranch(AJMP, T); + patch(p1, pc); + patch(p2, pc); + } if(!issigned[t->etype]) { nodconst(&nz, t, 0); gmove(&nz, dx); @@ -507,6 +553,8 @@ dodiv(int op, Type *t, Node *nl, Node *nr, Node *res, Node *ax, Node *dx) gmove(ax, res); else gmove(dx, res); + if(check) + patch(p3, pc); } static void @@ -553,13 +601,13 @@ cgen_div(int op, Node *nl, Node *nr, Node *res) if(is64(nl->type)) fatal("cgen_div %T", nl->type); - t = nl->type; - if(t->width == 1) - t = types[t->etype+2]; // int8 -> int16, uint8 -> uint16 - + if(issigned[nl->type->etype]) + t = types[TINT32]; + else + t = types[TUINT32]; savex(D_AX, &ax, &oldax, res, t); savex(D_DX, &dx, &olddx, res, t); - dodiv(op, t, nl, nr, res, &ax, &dx); + dodiv(op, nl, nr, res, &ax, &dx); restx(&dx, &olddx); restx(&ax, &oldax); } @@ -572,9 +620,9 @@ cgen_div(int op, Node *nl, Node *nr, Node *res) void cgen_shift(int op, Node *nl, Node *nr, Node *res) { - Node n1, n2, cx, oldcx; + Node n1, n2, nt, cx, oldcx, hi, lo; int a, w; - Prog *p1; + Prog *p1, *p2; uvlong sc; if(nl->type->width > 4) @@ -608,8 +656,13 @@ cgen_shift(int op, Node *nl, Node *nr, Node *res) gmove(&cx, &oldcx); } - nodreg(&n1, types[TUINT32], D_CX); - regalloc(&n1, nr->type, &n1); // to hold the shift type in CX + if(nr->type->width > 4) { + tempname(&nt, nr->type); + n1 = nt; + } else { + nodreg(&n1, types[TUINT32], D_CX); + regalloc(&n1, nr->type, &n1); // to hold the shift type in CX + } if(samereg(&cx, res)) regalloc(&n2, nl->type, N); @@ -624,8 +677,21 @@ cgen_shift(int op, Node *nl, Node *nr, Node *res) } // test and fix up large shifts - gins(optoas(OCMP, nr->type), &n1, ncon(w)); - p1 = gbranch(optoas(OLT, types[TUINT32]), T); + if(nr->type->width > 4) { + // delayed reg alloc + nodreg(&n1, types[TUINT32], D_CX); + regalloc(&n1, types[TUINT32], &n1); // to hold the shift type in CX + split64(&nt, &lo, &hi); + gmove(&lo, &n1); + gins(optoas(OCMP, types[TUINT32]), &hi, ncon(0)); + p2 = gbranch(optoas(ONE, types[TUINT32]), T); + gins(optoas(OCMP, types[TUINT32]), &n1, ncon(w)); + p1 = gbranch(optoas(OLT, types[TUINT32]), T); + patch(p2, pc); + } else { + gins(optoas(OCMP, nr->type), &n1, ncon(w)); + p1 = gbranch(optoas(OLT, types[TUINT32]), T); + } if(op == ORSH && issigned[nl->type->etype]) { gins(a, ncon(w-1), &n2); } else { |