On 12/03/14 21:26, Olivier Danet wrote:
Hi Olivier,
Here is a patch for handling this corner case on SPARC32.
SPARC64 division already checks this in helper_sdivx(), some other
architectures
seem to do the same (for example, target-arm/helper.c: HELPER(sdiv))
===================================================================
The integer division 0x8000_0000_0000_0000 / -1 must be handled separately
to avoid overflows on the QEMU host.
Signed-off-by: Olivier Danet <oda...@caramail.com>
-------------------------------------------------------------------
diff --git a/target-sparc/helper.c b/target-sparc/helper.c
index 57c20af..b6b5937 100644
--- a/target-sparc/helper.c
+++ b/target-sparc/helper.c
@@ -116,14 +116,16 @@ static target_ulong
helper_sdiv_common(CPUSPARCState *env, target_ulong a,
if (x1 == 0) {
cpu_restore_state(env, GETPC());
helper_raise_exception(env, TT_DIV_ZERO);
- }
-
- x0 = x0 / x1;
- if ((int32_t) x0 != x0) {
- x0 = x0 < 0 ? 0x80000000 : 0x7fffffff;
+ } else if (x1 == -1 && x0 == 0x8000000000000000) {
+ x0 = 0x7fffffff;
overflow = 1;
Thanks for the patch! I think based upon Peter's recent series that the
sign constant would need a ULL suffix in order to function correctly on
32-bit platforms.
My personal preference would be for (1ULL << 63) unless Peter (CC added)
can think of a reason to leave the hex constant in its current form?
That said, I've tested the patch on a Debian etch Linux image and it
works for me.
+ } else {
+ x0 = x0 / x1;
+ if ((int32_t) x0 != x0) {
+ x0 = x0 < 0 ? 0x80000000 : 0x7fffffff;
+ overflow = 1;
+ }
}
-
Looks like a whitespace change accidentally made it into this patch too.
if (cc) {
env->cc_dst = x0;
env->cc_src2 = overflow;
-------------------------------------------------------------------
ATB,
Mark.
