No difference in generated code, but the XOR-based formula is
easily understood on its own. This will make more sense once
ADD/SUB stop using dst^src1^src2 to compute AF.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
target/i386/tcg/cc_helper_template.h.inc | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/target/i386/tcg/cc_helper_template.h.inc
b/target/i386/tcg/cc_helper_template.h.inc
index 9aff16b8801..b821e5bca3b 100644
--- a/target/i386/tcg/cc_helper_template.h.inc
+++ b/target/i386/tcg/cc_helper_template.h.inc
@@ -175,13 +175,10 @@ static uint32_t glue(compute_all_logic, SUFFIX)(DATA_TYPE
dst, DATA_TYPE src1)
static uint32_t glue(compute_all_inc, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
{
uint32_t cf, pf, af, zf, sf, of;
- DATA_TYPE src2;
cf = src1;
- src1 = dst - 1;
- src2 = 1;
pf = compute_pf(dst);
- af = (dst ^ src1 ^ src2) & CC_A;
+ af = (dst ^ (dst - 1)) & CC_A; /* bits 0..3 are all clear */
zf = (dst == 0) * CC_Z;
sf = lshift(dst, 8 - DATA_BITS) & CC_S;
of = (dst == SIGN_MASK) * CC_O;
@@ -191,13 +188,10 @@ static uint32_t glue(compute_all_inc, SUFFIX)(DATA_TYPE
dst, DATA_TYPE src1)
static uint32_t glue(compute_all_dec, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
{
uint32_t cf, pf, af, zf, sf, of;
- DATA_TYPE src2;
cf = src1;
- src1 = dst + 1;
- src2 = 1;
pf = compute_pf(dst);
- af = (dst ^ src1 ^ src2) & CC_A;
+ af = (dst ^ (dst + 1)) & CC_A; /* bits 0..3 are all set */
zf = (dst == 0) * CC_Z;
sf = lshift(dst, 8 - DATA_BITS) & CC_S;
of = (dst == SIGN_MASK - 1) * CC_O;
--
2.49.0
