| Message ID | 532A1A30.3040306@caramail.com |
|---|---|
| State | New |
| Headers | show |
On 03/19/2014 03:29 PM, Olivier Danet wrote: > The signed integer division -0x8000_0000_0000_0000 / -1 must be handled > separately to avoid an overflow on the QEMU host. > > Signed-off-by: Olivier Danet <odanet@caramail.com> > --- > target-sparc/helper.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) Reviewed-by: Richard Henderson <rth@twiddle.net> r~
On 03/19/2014 03:29 PM, Olivier Danet wrote: > + if ((int32_t) x0 != x0) { > + x0 = x0 < 0 ? 0x80000000 : 0x7fffffff; > + overflow = 1; > + } Actually, there's an existing bug here that we might as well fix. ## ... the 32-bit result is sign-extended to 64 bits and ## written into register R[rd]. That 0x80000000 is not going to promote properly to 64-bits. We might as well go ahead and use INT32_MIN and INT32_MAX here at the same time. r~
diff --git a/target-sparc/helper.c b/target-sparc/helper.c index f3c7fbf..3822c48 100644 --- a/target-sparc/helper.c +++ b/target-sparc/helper.c @@ -122,12 +122,15 @@ static target_ulong helper_sdiv_common(CPUSPARCState *env, target_ulong a, if (x1 == 0) { cpu_restore_state(CPU(cpu), 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 == INT64_MIN) { + x0 = 0x7fffffff; overflow = 1; + } else { + x0 = x0 / x1; + if ((int32_t) x0 != x0) { + x0 = x0 < 0 ? 0x80000000 : 0x7fffffff; + overflow = 1; + } } if (cc) {
The signed integer division -0x8000_0000_0000_0000 / -1 must be handled separately to avoid an overflow on the QEMU host. Signed-off-by: Olivier Danet <odanet@caramail.com> --- target-sparc/helper.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)