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emit_x64_floating_point: FlushToZero is redundant as hardware already does FTZ

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This commit is contained in:
MerryMage 2018-07-31 16:08:13 +01:00
parent 822fd4a875
commit de9d8c461c
1 changed files with 0 additions and 42 deletions
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42
src/backend_x64/emit_x64_floating_point.cpp
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@ -97,33 +97,6 @@ void DenormalsAreZero(BlockOfCode& code, Xbyak::Xmm xmm_value, Xbyak::Reg64 gpr_
code.L(end);
}
template<size_t fsize>
void FlushToZero(BlockOfCode& code, Xbyak::Xmm xmm_value, Xbyak::Reg64 gpr_scratch) {
Xbyak::Label end;
if constexpr (fsize == 32) {
code.movd(gpr_scratch.cvt32(), xmm_value);
code.and_(gpr_scratch.cvt32(), u32(0x7FFFFFFF));
code.sub(gpr_scratch.cvt32(), u32(1));
code.cmp(gpr_scratch.cvt32(), u32(0x007FFFFE));
} else {
auto mask = code.MConst(xword, f64_non_sign_mask);
mask.setBit(64);
auto penult_denormal = code.MConst(xword, f64_penultimate_positive_denormal);
penult_denormal.setBit(64);
code.movq(gpr_scratch, xmm_value);
code.and_(gpr_scratch, mask);
code.sub(gpr_scratch, u32(1));
code.cmp(gpr_scratch, penult_denormal);
}
code.ja(end);
code.pxor(xmm_value, xmm_value);
code.mov(dword[r15 + code.GetJitStateInfo().offsetof_FPSCR_UFC], u32(1 << 3));
code.L(end);
}
template<size_t fsize>
void ZeroIfNaN(BlockOfCode& code, Xbyak::Xmm xmm_value, Xbyak::Xmm xmm_scratch) {
code.pxor(xmm_scratch, xmm_scratch);
@ -245,9 +218,6 @@ void FPTwoOp(BlockOfCode& code, EmitContext& ctx, IR::Inst* inst, Function fn) {
} else {
fn(result);
}
if (ctx.FPSCR_FTZ()) {
FlushToZero<fsize>(code, result, gpr_scratch);
}
if (ctx.FPSCR_DN()) {
DefaultNaN<fsize>(code, result);
} else if (ctx.AccurateNaN()) {
@ -283,9 +253,6 @@ void FPThreeOp(BlockOfCode& code, EmitContext& ctx, IR::Inst* inst, [[maybe_unus
} else {
fn(result, operand);
}
if (ctx.FPSCR_FTZ()) {
FlushToZero<fsize>(code, result, gpr_scratch);
}
if (ctx.FPSCR_DN()) {
DefaultNaN<fsize>(code, result);
} else if (ctx.AccurateNaN()) {
@ -321,9 +288,6 @@ void FPFourOp(BlockOfCode& code, EmitContext& ctx, IR::Inst* inst, Function fn,
PreProcessNaNs<fsize>(code, ctx, result, operand2, operand3, end, nan_handler);
}
fn(result, operand2, operand3);
if (ctx.FPSCR_FTZ()) {
FlushToZero<fsize>(code, result, gpr_scratch);
}
if (ctx.FPSCR_DN()) {
DefaultNaN<fsize>(code, result);
} else if (ctx.AccurateNaN()) {
@ -923,9 +887,6 @@ void EmitX64::EmitFPSingleToDouble(EmitContext& ctx, IR::Inst* inst) {
DenormalsAreZero<32>(code, result, gpr_scratch);
}
code.cvtss2sd(result, result);
if (ctx.FPSCR_FTZ()) {
FlushToZero<64>(code, result, gpr_scratch);
}
if (ctx.FPSCR_DN()) {
DefaultNaN<64>(code, result);
}
@ -942,9 +903,6 @@ void EmitX64::EmitFPDoubleToSingle(EmitContext& ctx, IR::Inst* inst) {
DenormalsAreZero<64>(code, result, gpr_scratch);
}
code.cvtsd2ss(result, result);
if (ctx.FPSCR_FTZ()) {
FlushToZero<32>(code, result, gpr_scratch);
}
if (ctx.FPSCR_DN()) {
DefaultNaN<32>(code, result);
}