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SH-2 recompiler: compare for CMP/EQ on AArch64 (ST-V black screens) (#2187)

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jit_cmp() asked the flags of the compare with SLJIT_SET(cond & ~1). For
SLJIT_EQUAL that is SLJIT_SET(0), no flag at all: the x86 back ends
compare anyway, the AArch64 one does not, so CMP/EQ Rm,Rn and CMP/EQ
#imm,R0 set T from stale flags. The ST-V BIOS then took wrong branches
and games stayed on a black screen or ran with broken graphics with the
SH-2 Dynarec option on. The zero flag is now asked with SLJIT_SET_Z, as
the SH-3 recompiler already does.


Claude-Session: https://claude.ai/code/session_013Vje3pEtpLHubqCGwCgoQX

Co-authored-by: Claude Opus 5.5 <[email protected]>
This commit is contained in:
zanacandClaude Opus 5.5 authored and GitHub committed 2026-10-31 15:46:16 -04:00
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commit b168882c39
1 file changed
+4 -2
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src/cpu/sh2/sh2jit.c
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@@ -593,10 +593,12 @@ static void jit_alu(struct sljit_compiler *C, sljit_s32 op, int n, sljit_s32 src
sljit_emit_op1(C, SLJIT_MOV32, JREG(n), SLJIT_R0, 0);
}
/* T = (src1 cmp src2) */
/* T = (src1 cmp src2). The zero flag is asked with SLJIT_SET_Z: SLJIT_SET(SLJIT_EQUAL)
is 0, no flag at all, and the AArch64 back end then does not compare */
static void jit_cmp(struct sljit_compiler *C, sljit_s32 cond, sljit_s32 src1, sljit_sw src1w, sljit_s32 src2, sljit_sw src2w)
{
sljit_emit_op2u(C, SLJIT_SUB32 | SLJIT_SET(cond & ~1), src1, src1w, src2, src2w);
sljit_s32 setf = (cond == SLJIT_EQUAL) ? SLJIT_SET_Z : SLJIT_SET(cond & ~1);
sljit_emit_op2u(C, SLJIT_SUB32 | setf, src1, src1w, src2, src2w);
jit_set_t(C, cond);
}