diff options
| author | Sintendo <3380580+Sintendo@users.noreply.github.com> | 2025-02-01 21:11:23 +0100 |
|---|---|---|
| committer | Sintendo <3380580+Sintendo@users.noreply.github.com> | 2025-02-02 12:57:59 +0100 |
| commit | b7c3f91643535b760a71de5b1faaae2b91ac7af2 (patch) | |
| tree | 58d3f583ceeef4f318b98fa1465bacbaf89434a4 | |
| parent | c5870ed0c71d3821b792543631937110e2d27202 (diff) | |
JitArm64_Integer: cmpl - Subtract 12-bit constant
You can encode a 12-bit immediate in a SUB instruction on ARM64. We can
exploit this to avoid materializing the immediate.
This approach saves an instruction if it does not need to be
materialized in a register afterwards. Otherwise, we just materialize
it later and the total number of instructions stays the same.
Before:
0x5280003a mov w26, #0x1 ; =1
0xcb1a033b sub x27, x25, x26
After:
0xd100073b sub x27, x25, #0x1
| -rw-r--r-- | Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp index 518922343d..ef44a72efd 100644 --- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp +++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Integer.cpp @@ -728,9 +728,13 @@ void JitArm64::cmpl(UGeckoInstruction inst) { NEG(CR, EncodeRegTo64(gpr.R(b))); } - else if (gpr.IsImm(b) && !gpr.GetImm(b)) + else if (gpr.IsImm(b) && (gpr.GetImm(b) & 0xFFF) == gpr.GetImm(b)) { - MOV(EncodeRegTo32(CR), gpr.R(a)); + const u32 imm = gpr.GetImm(b); + if (imm == 0) + MOV(EncodeRegTo32(CR), gpr.R(a)); + else + SUB(CR, EncodeRegTo64(gpr.R(a)), imm); } else { |