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JitArm64: Optimize frsqrte denormal path (in an "interesting" way)

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This commit is contained in:
JosJuice 2023-10-11 21:48:41 +02:00
parent 9b21046dfc
commit 9cc1df6c14
1 changed files with 3 additions and 3 deletions
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6
Source/Core/Core/PowerPC/JitArm64/JitAsm.cpp
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@ -329,12 +329,12 @@ void JitArm64::GenerateFrsqrte()
FixupBranch negative = TBNZ(ARM64Reg::X1, 63); FixupBranch negative = TBNZ(ARM64Reg::X1, 63);
FixupBranch normal = CBNZ(ARM64Reg::X2); FixupBranch normal = CBNZ(ARM64Reg::X2);
// "Normalize" denormal values // "Normalize" denormal values.
// The simplified calculation used here results in the upper 11 bits being incorrect,
// but that's fine, because the code below never reads those bits.
CLZ(ARM64Reg::X3, ARM64Reg::X1); CLZ(ARM64Reg::X3, ARM64Reg::X1);
MOVI2R(ARM64Reg::X2, 12);
LSLV(ARM64Reg::X1, ARM64Reg::X1, ARM64Reg::X3); LSLV(ARM64Reg::X1, ARM64Reg::X1, ARM64Reg::X3);
LSR(ARM64Reg::X1, ARM64Reg::X1, 11); LSR(ARM64Reg::X1, ARM64Reg::X1, 11);
SUB(ARM64Reg::X3, ARM64Reg::X2, ARM64Reg::X3);
BFI(ARM64Reg::X1, ARM64Reg::X3, 52, 12); BFI(ARM64Reg::X1, ARM64Reg::X3, 52, 12);
SetJumpTarget(normal); SetJumpTarget(normal);