The-Homebrew-Cloud/dolphin
2
0
Fork 0
mirror of https://github.com/dolphin-emu/dolphin.git synced 2025-02-11 06:59:07 +01:00
Code Issues Packages Projects Releases Wiki Activity

JitArm64_Integer: Optimize subfic for zero

Browse Source 
When the immediate value is zero, we can do a negation. On ARM64 the NEG
/NEGS instructions are just an alias for SUB/SUBS with a hardcoded WZR.

Before:
```
ldr    w22, [x29, #0x28]
mov    w21, #0x0                 ; =0
subs   w22, w21, w22
```

After:
```
ldr    w22, [x29, #0x28]
negs   w22, w22
```
This commit is contained in:
Sintendo 2024-06-26 00:07:20 +02:00
parent f49659fbfc
commit d877cfa4e2
1 changed files with 10 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp
View File

@ -1392,13 +1392,19 @@ void JitArm64::subfic(UGeckoInstruction inst)
} }
else else
{ {
const bool allocate_reg = d == a; const bool will_read = d == a;
gpr.BindToRegister(d, allocate_reg); const bool is_zero = imm == 0;
const bool allocate_reg = will_read && !is_zero;
gpr.BindToRegister(d, will_read);
// d = imm - a // d = imm - a
ARM64Reg RD = gpr.R(d); ARM64Reg RD = gpr.R(d);
ARM64Reg WA = allocate_reg ? gpr.GetReg() : RD; ARM64Reg WA = ARM64Reg::WZR;
if (!is_zero)
{
WA = will_read ? gpr.GetReg() : RD;
MOVI2R(WA, imm); MOVI2R(WA, imm);
}
CARRY_IF_NEEDED(SUB, SUBS, RD, WA, gpr.R(a)); CARRY_IF_NEEDED(SUB, SUBS, RD, WA, gpr.R(a));
if (allocate_reg) if (allocate_reg)