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Smaller ComputeMemoryAddress/Offset sequence 

Replace a movzx after setae in both ComputeMemoryAddressOffset and ComputeMemoryAddress with a xor_ of eax prior to the cmp. This reduces the length in bytes of both sequences by 1, and should be a moderate ICache usage reduction thanks to the frequency of these sequences.
This commit is contained in:
chrisps 2020-01-17 07:28:36 -08:00 committed by Gliniak
parent 166be463be
commit 9dfbef8acf
1 changed files with 2 additions and 2 deletions
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4
src/xenia/cpu/backend/x64/x64_seq_memory.cc
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@ -52,9 +52,9 @@ RegExp ComputeMemoryAddressOffset(X64Emitter& e, const T& guest,
if (xe::memory::allocation_granularity() > 0x1000) {
// Emulate the 4 KB physical address offset in 0xE0000000+ when can't do
// it via memory mapping.
e.xor_(e.eax, e.eax);
e.cmp(guest.reg().cvt32(), 0xE0000000 - offset_const);
e.setae(e.al);
e.movzx(e.eax, e.al);
e.shl(e.eax, 12);
e.add(e.eax, guest.reg().cvt32());
} else {
@ -89,9 +89,9 @@ RegExp ComputeMemoryAddress(X64Emitter& e, const T& guest) {
if (xe::memory::allocation_granularity() > 0x1000) {
// Emulate the 4 KB physical address offset in 0xE0000000+ when can't do
// it via memory mapping.
e.xor_(e.eax, e.eax);
e.cmp(guest.reg().cvt32(), 0xE0000000);
e.setae(e.al);
e.movzx(e.eax, e.al);
e.shl(e.eax, 12);
e.add(e.eax, guest.reg().cvt32());
} else {