| Message ID | 20170615081711.25347-2-laurent@vivier.eu |
|---|---|
| State | New |
| Headers | show |
diff --git a/target/m68k/translate.c b/target/m68k/translate.c index ad4d4ef..52653f6 100644 --- a/target/m68k/translate.c +++ b/target/m68k/translate.c @@ -565,7 +565,7 @@ static void gen_flush_flags(DisasContext *s) t1 = tcg_temp_new(); tcg_gen_add_i32(t0, QREG_CC_N, QREG_CC_V); gen_ext(t0, t0, s->cc_op - CC_OP_SUBB, 1); - tcg_gen_xor_i32(t1, QREG_CC_N, QREG_CC_V); + tcg_gen_xor_i32(t1, QREG_CC_N, t0); tcg_gen_xor_i32(QREG_CC_V, QREG_CC_V, t0); tcg_temp_free(t0); tcg_gen_and_i32(QREG_CC_V, QREG_CC_V, t1);
V flag for subtraction is: v = (res ^ src1) & (src1 ^ src2) (see COMPUTE_CCR() in target/m68k/helper.c) But gen_flush_flags() uses: v = (res ^ src2) & (src1 ^ src2) The problem has been found with the following program: .global _start _start: move.l #-2147483648,%d0 subq.l #1,%d0 jvc 1f move.l #1,%d1 move.l #1,%d0 trap #0 1: move.l #0,%d1 move.l #1,%d0 trap #0 It works fine (exit(1)) on real hardware, and with "-singlestep". "-singlestep" uses gen_helper_flush_flags(), whereas without "-singlestep", V flag is computed directly in gen_flush_flags(). This patch updates gen_flush_flags() to have the same result as with gen_helper_flush_flags(). Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <rth@twiddle.net> Message-Id: <20170614203905.19657-1-laurent@vivier.eu> --- target/m68k/translate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)