From 0637a7ec597d6b96ac9b6274f390bf2ee22807fd Mon Sep 17 00:00:00 2001 From: Sintendo Date: Thu, 4 Mar 2021 22:16:52 +0100 Subject: [PATCH] Jit64: divwx - Optimize power-of-two divisors Power-of-two divisors can be done more elegantly, so handle them separately. - Division by 4 Before: 41 BD 04 00 00 00 mov r13d,4 41 8B C0 mov eax,r8d 45 85 ED test r13d,r13d 74 0D je overflow 3D 00 00 00 80 cmp eax,80000000h 75 0E jne normal_path 41 83 FD FF cmp r13d,0FFFFFFFFh 75 08 jne normal_path overflow: C1 F8 1F sar eax,1Fh 44 8B E8 mov r13d,eax EB 07 jmp done normal_path: 99 cdq 41 F7 FD idiv eax,r13d 44 8B E8 mov r13d,eax done: After: 45 85 C0 test r8d,r8d 45 8D 68 03 lea r13d,[r8+3] 45 0F 49 E8 cmovns r13d,r8d 41 C1 FD 02 sar r13d,2 --- .../Core/Core/PowerPC/Jit64/Jit_Integer.cpp | 21 +++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp b/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp index 41bd9d6ea7..e673a52b6d 100644 --- a/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp +++ b/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp @@ -1460,6 +1460,27 @@ void Jit64::divwx(UGeckoInstruction inst) SetJumpTarget(done); } + else if (MathUtil::IsPow2(divisor) || MathUtil::IsPow2(-divisor)) + { + u32 abs_val = std::abs(divisor); + + X64Reg tmp = RSCRATCH; + if (Ra.IsSimpleReg() && Ra.GetSimpleReg() != Rd) + tmp = Ra.GetSimpleReg(); + else + MOV(32, R(tmp), Ra); + + TEST(32, R(tmp), R(tmp)); + LEA(32, Rd, MDisp(tmp, abs_val - 1)); + CMOVcc(32, Rd, R(tmp), CC_NS); + SAR(32, Rd, Imm8(IntLog2(abs_val))); + + if (divisor < 0) + NEG(32, Rd); + + if (inst.OE) + GenerateConstantOverflow(false); + } else { // Optimize signed 32-bit integer division by a constant