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[a64] Detect `MOVI` utilizations for vector-element splats(u8,u16,u32) 

The 64-bit cases uses a particular Replicated 8-bit immediate so
something else will have to handle that  This cases a lot of cases
without having to touch memory. Does not catch cases of
`1.0`(0x3f800000).
This commit is contained in:
Wunkolo 2024-05-28 14:39:10 -07:00
parent f830f790d1
commit 8f6c0ad985
1 changed files with 54 additions and 4 deletions
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58
src/xenia/cpu/backend/a64/a64_emitter.cc
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@ -848,11 +848,61 @@ void A64Emitter::LoadConstantV(oaknut::QReg dest, const vec128_t& v) {
} else if (v.low == ~uint64_t(0) && v.high == ~uint64_t(0)) {
// 1111...
MOVI(dest.B16(), 0xFF);
} else if (std::adjacent_find(std::cbegin(v.u8), std::cend(v.u8),
std::not_equal_to<>()) == std::cend(v.u8)) {
// 0xXX, 0xXX, 0xXX...
MOVI(dest.B16(), v.u8[0]);
} else {
// Try to figure out some common splat-patterns to utilize MOVI rather than
// stashing to memory.
const bool all_same_u8 =
std::adjacent_find(std::cbegin(v.u8), std::cend(v.u8),
std::not_equal_to<>()) == std::cend(v.u8);
if (all_same_u8) {
// 0xXX, 0xXX, 0xXX...
MOVI(dest.B16(), v.u8[0]);
return;
}
const bool all_same_u16 =
std::adjacent_find(std::cbegin(v.u16), std::cend(v.u16),
std::not_equal_to<>()) == std::cend(v.u16);
if (all_same_u16) {
if ((v.u16[0] & 0xFF00) == 0) {
// 0x00XX, 0x00XX, 0x00XX...
MOVI(dest.H8(), uint8_t(v.u16[0]));
return;
} else if ((v.u16[0] & 0x00FF) == 0) {
// 0xXX00, 0xXX00, 0xXX00...
MOVI(dest.H8(), uint8_t(v.u16[0] >> 8), oaknut::util::LSL, 8);
return;
}
}
const bool all_same_u32 =
std::adjacent_find(std::cbegin(v.u32), std::cend(v.u32),
std::not_equal_to<>()) == std::cend(v.u32);
if (all_same_u32) {
if ((v.u32[0] & 0x00FFFFFF) == 0) {
// This is used a lot for certain float-splats and should be checked
// first before the others
// 0xXX000000, 0xXX000000, 0xXX000000...
MOVI(dest.S4(), uint8_t(v.u32[0] >> 24), oaknut::util::LSL, 24);
return;
} else if ((v.u32[0] & 0xFFFFFF00) == 0) {
// 0x000000XX, 0x000000XX, 0x000000XX...
MOVI(dest.S4(), uint8_t(v.u32[0]));
return;
} else if ((v.u32[0] & 0xFFFF00FF) == 0) {
// 0x0000XX00, 0x0000XX00, 0x0000XX00...
MOVI(dest.S4(), uint8_t(v.u32[0] >> 8), oaknut::util::LSL, 8);
return;
} else if ((v.u32[0] & 0xFF00FFFF) == 0) {
// 0x00XX0000, 0x00XX0000, 0x00XX0000...
MOVI(dest.S4(), uint8_t(v.u32[0] >> 16), oaknut::util::LSL, 16);
return;
}
}
// TODO(benvanik): see what other common values are.
// TODO(benvanik): build constant table - 99% are reused.
MovMem64(SP, kStashOffset, v.low);