On 07/01/2026 04:52, Paolo Bonzini wrote:
The value that is pushed by PUSHF is the full EFLAGS, while CC_OP_EFLAGS
only wants arithmetic flags in CC_SRC. To avoid this, follow what other
helpers to and set CC_SRC/CC_OP directly in helper_read_eflags. This
is basically free and fixes an issue booting Windows 3.11.
Reported-by: Mark Cave-Ayland <[email protected]>
Fixes: e661e2d7a37 ("target/i386/tcg: update cc_op after PUSHF", 2025-12-27)
Signed-off-by: Paolo Bonzini <[email protected]>
---
target/i386/tcg/cc_helper.c | 4 +++-
target/i386/tcg/emit.c.inc | 3 +--
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/target/i386/tcg/cc_helper.c b/target/i386/tcg/cc_helper.c
index 91e492196af..6ddd64fcb07 100644
--- a/target/i386/tcg/cc_helper.c
+++ b/target/i386/tcg/cc_helper.c
@@ -414,7 +414,9 @@ target_ulong helper_read_eflags(CPUX86State *env)
{
uint32_t eflags;
- eflags = cpu_cc_compute_all(env);
+ CC_SRC = eflags = cpu_cc_compute_all(env);
+ CC_OP = CC_OP_EFLAGS;
+
eflags |= (env->df & DF_MASK);
eflags |= env->eflags & ~(VM_MASK | RF_MASK);
return eflags;
diff --git a/target/i386/tcg/emit.c.inc b/target/i386/tcg/emit.c.inc
index 0fde3d669d9..e55b65176fc 100644
--- a/target/i386/tcg/emit.c.inc
+++ b/target/i386/tcg/emit.c.inc
@@ -3253,8 +3253,7 @@ static void gen_PUSHF(DisasContext *s, X86DecodedInsn
*decode)
gen_update_cc_op(s);
gen_helper_read_eflags(s->T0, tcg_env);
gen_push_v(s, s->T0);
- decode->cc_src = s->T0;
- decode->cc_op = CC_OP_EFLAGS;
+ assume_cc_op(s, CC_OP_EFLAGS);
}
static MemOp gen_shift_count(DisasContext *s, X86DecodedInsn *decode,
Thanks Paolo! I've given this a quick test and it fixes the issue here:
Tested-by: Mark Cave-Ayland <[email protected]>
ATB,
Mark.
