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backend/x64: Update FpFixup constants with denormal behavior

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There is an important subtlety that should be documented here. All the
operands of `FpFixup` that read from the `Src` register actually do a
`DAZ` operation if `MXCSR.DAZ` is set.
This commit is contained in:
Wunkolo 2021-05-31 17:15:48 -07:00 committed by merry
parent 94f84cf1ef
commit 3ed2aebb20
1 changed files with 12 additions and 12 deletions
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24
src/dynarmic/backend/x64/constants.h
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@ -97,13 +97,13 @@ constexpr u8 SNaN = 0b10000000;
// Opcodes for use with vfixupimm
enum class FpFixup : u8 {
A = 0b0000, // A
B = 0b0001, // B
QNaN_B = 0b0010, // QNaN with sign of B
Dest = 0b0000, // Preserve destination
Norm_Src = 0b0001, // Source operand (Denormal as positive-zero)
QNaN_Src = 0b0010, // QNaN with sign of source (Denormal as positive-zero)
IndefNaN = 0b0011, // Indefinite QNaN (Negative QNaN with no payload on x86)
NegInf = 0b0100, // -Infinity
PosInf = 0b0101, // +Infinity
Inf_B = 0b0110, // Infinity with sign of B
Inf_Src = 0b0110, // Infinity with sign of source (Denormal as positive-zero)
NegZero = 0b0111, // -0.0
PosZero = 0b1000, // +0.0
NegOne = 0b1001, // -1.0
@ -116,14 +116,14 @@ enum class FpFixup : u8 {
};
// Generates 32-bit LUT for vfixupimm instruction
constexpr u32 FixupLUT(FpFixup src_qnan = FpFixup::A,
FpFixup src_snan = FpFixup::A,
FpFixup src_zero = FpFixup::A,
FpFixup src_posone = FpFixup::A,
FpFixup src_neginf = FpFixup::A,
FpFixup src_posinf = FpFixup::A,
FpFixup src_pos = FpFixup::A,
FpFixup src_neg = FpFixup::A) {
constexpr u32 FixupLUT(FpFixup src_qnan = FpFixup::Dest,
FpFixup src_snan = FpFixup::Dest,
FpFixup src_zero = FpFixup::Dest,
FpFixup src_posone = FpFixup::Dest,
FpFixup src_neginf = FpFixup::Dest,
FpFixup src_posinf = FpFixup::Dest,
FpFixup src_pos = FpFixup::Dest,
FpFixup src_neg = FpFixup::Dest) {
u32 fixup_lut = 0;
fixup_lut = mcl::bit::set_bits<0, 3, u32>(fixup_lut, static_cast<u32>(src_qnan));
fixup_lut = mcl::bit::set_bits<4, 7, u32>(fixup_lut, static_cast<u32>(src_snan));