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emit_x64_vector_floating_point: Hardware FMA implementation for RSqrtStepFused

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This commit is contained in:
MerryMage 2018-09-12 21:01:06 +01:00
parent e553c4fe8d
commit 06ba397af2
1 changed files with 51 additions and 5 deletions
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56
src/backend/x64/emit_x64_vector_floating_point.cpp
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@ -979,21 +979,67 @@ void EmitX64::EmitFPVectorRSqrtEstimate64(EmitContext& ctx, IR::Inst* inst) {
EmitRSqrtEstimate<u64>(code, ctx, inst);
}
template<typename FPT>
template<size_t fsize>
static void EmitRSqrtStepFused(BlockOfCode& code, EmitContext& ctx, IR::Inst* inst) {
EmitThreeOpFallback(code, ctx, inst, [](VectorArray<FPT>& result, const VectorArray<FPT>& op1, const VectorArray<FPT>& op2, FP::FPCR fpcr, FP::FPSR& fpsr) {
using FPT = mp::unsigned_integer_of_size<fsize>;
const auto fallback_fn = [](VectorArray<FPT>& result, const VectorArray<FPT>& op1, const VectorArray<FPT>& op2, FP::FPCR fpcr, FP::FPSR& fpsr) {
for (size_t i = 0; i < result.size(); i++) {
result[i] = FP::FPRSqrtStepFused<FPT>(op1[i], op2[i], fpcr, fpsr);
}
});
};
if (code.DoesCpuSupport(Xbyak::util::Cpu::tFMA) && code.DoesCpuSupport(Xbyak::util::Cpu::tAVX)) {
auto args = ctx.reg_alloc.GetArgumentInfo(inst);
const Xbyak::Xmm result = ctx.reg_alloc.ScratchXmm();
const Xbyak::Xmm operand1 = ctx.reg_alloc.UseXmm(args[0]);
const Xbyak::Xmm operand2 = ctx.reg_alloc.UseXmm(args[1]);
const Xbyak::Xmm tmp = ctx.reg_alloc.ScratchXmm();
const Xbyak::Xmm mask = ctx.reg_alloc.ScratchXmm();
Xbyak::Label end, fallback;
code.vmovaps(result, GetVectorOf<fsize, false, 0, 3>(code));
FCODE(vfnmadd231p)(result, operand1, operand2);
// An explanation for this is given in EmitFPRSqrtStepFused.
code.vmovaps(mask, GetVectorOf<fsize, fsize == 32 ? 0x7f000000 : 0x7fe0000000000000>(code));
FCODE(vandp)(tmp, result, mask);
if constexpr (fsize == 32) {
code.vpcmpeqd(tmp, tmp, mask);
} else {
code.vpcmpeqq(tmp, tmp, mask);
}
code.ptest(tmp, tmp);
code.jnz(fallback, code.T_NEAR);
FCODE(vmulp)(result, result, GetVectorOf<fsize, false, -1, 1>(code));
code.L(end);
code.SwitchToFarCode();
code.L(fallback);
code.sub(rsp, 8);
ABI_PushCallerSaveRegistersAndAdjustStackExcept(code, HostLocXmmIdx(result.getIdx()));
EmitThreeOpFallbackWithoutRegAlloc(code, ctx, result, operand1, operand2, fallback_fn);
ABI_PopCallerSaveRegistersAndAdjustStackExcept(code, HostLocXmmIdx(result.getIdx()));
code.add(rsp, 8);
code.jmp(end, code.T_NEAR);
code.SwitchToNearCode();
ctx.reg_alloc.DefineValue(inst, result);
return;
}
EmitThreeOpFallback(code, ctx, inst, fallback_fn);
}
void EmitX64::EmitFPVectorRSqrtStepFused32(EmitContext& ctx, IR::Inst* inst) {
EmitRSqrtStepFused<u32>(code, ctx, inst);
EmitRSqrtStepFused<32>(code, ctx, inst);
}
void EmitX64::EmitFPVectorRSqrtStepFused64(EmitContext& ctx, IR::Inst* inst) {
EmitRSqrtStepFused<u64>(code, ctx, inst);
EmitRSqrtStepFused<64>(code, ctx, inst);
}
void EmitX64::EmitFPVectorS32ToSingle(EmitContext& ctx, IR::Inst* inst) {