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Fix overflow conditions for MIPS add / subtract (Stefan Weil) 

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@1828 c046a42c-6fe2-441c-8c8c-71466251a162
master
bellard 2006-04-23 15:18:58 +00:00
parent da2414e933
commit 76e050c2e6
1 changed files with 4 additions and 2 deletions
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6
target-mips/op.c
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@ -206,7 +206,8 @@ void op_addo (void)
tmp = T0;
T0 += T1;
if ((T0 >> 31) ^ (T1 >> 31) ^ (tmp >> 31)) {
if (((tmp ^ T1 ^ (-1)) & (T0 ^ T1)) >> 31) {
/* operands of same sign, result different sign */
CALL_FROM_TB1(do_raise_exception_direct, EXCP_OVERFLOW);
}
RETURN();
@ -224,7 +225,8 @@ void op_subo (void)
tmp = T0;
T0 = (int32_t)T0 - (int32_t)T1;
if (!((T0 >> 31) ^ (T1 >> 31) ^ (tmp >> 31))) {
if (((tmp ^ T1) & (tmp ^ T0)) >> 31) {
/* operands of different sign, first operand and result different sign */
CALL_FROM_TB1(do_raise_exception_direct, EXCP_OVERFLOW);
}
RETURN();