target-alpha: overflow condition for sublv and subqv

The conditions to detect overflow in sub operations was wrong.

This patch is necessary to boot Tru64.

Signed-off-by: Tristan Gingold <gingold@adacore.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7073 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 8 insertions, 8 deletions

diff --git a/target-alpha/op_helper.c b/target-alpha/op_helper.c
index 7ad1b3d55c..e61fa7396c 100644
--- a/target-alpha/op_helper.c
+++ b/target-alpha/op_helper.c
@@ -158,22 +158,22 @@ uint64_t helper_addlv (uint64_t op1, uint64_t op2)
 
 uint64_t helper_subqv (uint64_t op1, uint64_t op2)
 {
-    uint64_t tmp = op1;
-    op1 -= op2;
-    if (unlikely(((~tmp) ^ op1 ^ (-1ULL)) & ((~tmp) ^ op2) & (1ULL << 63))) {
+    uint64_t res;
+    res = op1 - op2;
+    if (unlikely((op1 ^ op2) & (res ^ op1) & (1ULL << 63))) {
         helper_excp(EXCP_ARITH, EXCP_ARITH_OVERFLOW);
     }
-    return op1;
+    return res;
 }
 
 uint64_t helper_sublv (uint64_t op1, uint64_t op2)
 {
-    uint64_t tmp = op1;
-    op1 = (uint32_t)(op1 - op2);
-    if (unlikely(((~tmp) ^ op1 ^ (-1UL)) & ((~tmp) ^ op2) & (1UL << 31))) {
+    uint32_t res;
+    res = op1 - op2;
+    if (unlikely((op1 ^ op2) & (res ^ op1) & (1UL << 31))) {
         helper_excp(EXCP_ARITH, EXCP_ARITH_OVERFLOW);
     }
-    return op1;
+    return res;
 }
 
 uint64_t helper_mullv (uint64_t op1, uint64_t op2)