From dfb32040bf2550a6592621544e306fad9c4f1dcb Mon Sep 17 00:00:00 2001 From: Sintendo Date: Tue, 2 Nov 2021 23:52:21 +0100 Subject: [PATCH] Jit64: divwx - Micro-optimize division by 2 Prefer using eax to isolate the sign bit. This saves a byte when the destination ends up as r8-15, because those require a REX prefix. Before: 41 8B C5 mov eax,r13d 41 C1 ED 1F shr r13d,1Fh 44 03 E8 add r13d,eax 41 D1 FD sar r13d,1 After: 41 8B C5 mov eax,r13d C1 E8 1F shr eax,1Fh 44 03 E8 add r13d,eax 41 D1 FD sar r13d,1 --- Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp b/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp index d34b432db9..13e654eab5 100644 --- a/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp +++ b/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp @@ -1494,6 +1494,8 @@ void Jit64::divwx(UGeckoInstruction inst) else if (divisor == 2 || divisor == -2) { X64Reg tmp = RSCRATCH; + X64Reg sign = tmp; + if (!Ra.IsSimpleReg()) { // Load dividend from memory @@ -1510,9 +1512,10 @@ void Jit64::divwx(UGeckoInstruction inst) // Copy dividend directly into destination MOV(32, Rd, Ra); tmp = Ra.GetSimpleReg(); + sign = Rd; } - SHR(32, Rd, Imm8(31)); + SHR(32, R(sign), Imm8(31)); ADD(32, Rd, R(tmp)); SAR(32, Rd, Imm8(1));