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[a64] Optimize zero MovMem64 

Read direction from the ZR in the case that we are just storing a 64 or 32 bit zero
This commit is contained in:
Wunkolo 2024-05-27 13:17:44 -07:00
parent 7b9f791cab
commit 818a77356e
1 changed files with 7 additions and 15 deletions
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22
src/xenia/cpu/backend/a64/a64_emitter.cc
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@ -645,7 +645,6 @@ oaknut::XReg A64Emitter::GetContextReg() { return X27; }
oaknut::XReg A64Emitter::GetMembaseReg() { return X28; }
void A64Emitter::ReloadContext() {
// mov(GetContextReg(), qword[rsp + StackLayout::GUEST_CTX_HOME]);
LDR(GetContextReg(), SP, StackLayout::GUEST_CTX_HOME);
}
@ -667,20 +666,13 @@ bool A64Emitter::ConstantFitsIn32Reg(uint64_t v) {
void A64Emitter::MovMem64(const oaknut::XRegSp& addr, intptr_t offset,
uint64_t v) {
// if ((v & ~0x7FFFFFFF) == 0) {
// // Fits under 31 bits, so just load using normal mov.
// mov(qword[addr], v);
// } else if ((v & ~0x7FFFFFFF) == ~0x7FFFFFFF) {
// // Negative number that fits in 32bits.
// mov(qword[addr], v);
// } else if (!(v >> 32)) {
// // All high bits are zero. It'd be nice if we had a way to load a 32bit
// // immediate without sign extending!
// // TODO(benvanik): this is super common, find a better way.
// mov(dword[addr], static_cast<uint32_t>(v));
// mov(dword[addr + 4], 0);
// } else
{
if (v == 0) {
STR(XZR, addr, offset);
} else if (!(v >> 32)) {
// All high bits are zero, 32-bit MOV
MOV(W0, static_cast<uint32_t>(v));
STR(X0, addr, offset);
} else {
// 64bit number that needs double movs.
MOV(X0, v);
STR(X0, addr, offset);