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emit_x64_vector: Implement AVX2 AVShift64

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zmt00 2024-02-22 19:27:36 -08:00 committed by merry
parent 879142d424
commit f884bc0dfc
1 changed files with 34 additions and 0 deletions
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34
src/dynarmic/backend/x64/emit_x64_vector.cpp
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@ -692,6 +692,40 @@ void EmitX64::EmitVectorArithmeticVShift64(EmitContext& ctx, IR::Inst* inst) {
return;
}
if (code.HasHostFeature(HostFeature::AVX2)) {
auto args = ctx.reg_alloc.GetArgumentInfo(inst);
const Xbyak::Xmm a = ctx.reg_alloc.UseScratchXmm(args[0]);
const Xbyak::Xmm b = ctx.reg_alloc.UseScratchXmm(args[1]);
const Xbyak::Xmm result = ctx.reg_alloc.ScratchXmm();
const Xbyak::Xmm negative_mask = ctx.reg_alloc.ScratchXmm();
// negative_mask = a < 0 ? 1s : 0s
code.vpxor(xmm0, xmm0, xmm0);
code.vpcmpgtq(negative_mask, xmm0, a);
// store sign bit of lowest byte of each element of b to select left/right shift later
code.vpsllq(xmm0, b, 56);
// sse/avx shifts are only positive, with dedicated left/right forms - shift by lowest byte of abs(b)
code.vpabsb(b, b);
code.vpand(b, b, code.BConst<64>(xword, 0xFF));
// calculate shifts
code.vpsllvq(result, a, b);
// implement variable arithmetic shift in terms of logical shift
// if a is negative, invert it, shift in leading 0s, then invert it again - noop if positive
code.vpxor(a, a, negative_mask);
code.vpsrlvq(a, a, b);
code.vpxor(a, a, negative_mask);
code.blendvpd(result, a); // implicit argument: xmm0 (sign of lowest byte of b)
ctx.reg_alloc.DefineValue(inst, result);
return;
}
EmitTwoArgumentFallback(code, ctx, inst, [](VectorArray<s64>& result, const VectorArray<s64>& a, const VectorArray<s64>& b) {
std::transform(a.begin(), a.end(), b.begin(), result.begin(), VShift<s64>);
});