| Message ID | 20091015210846.GB7071@volta.aurel32.net |
|---|---|
| State | New |
| Headers | show |
On Thu, Oct 15, 2009 at 11:08 PM, Aurelien Jarno <aurelien@aurel32.net> wrote: > (INT32_MIN / -1) triggers an overflow, and the result depends on the > host architecture (INT32_MIN on arm, -1 on ppc, SIGFPE on x86). Use a > test to output the correct value. > > Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> > --- > target-arm/helper.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/target-arm/helper.c b/target-arm/helper.c > index 701629a..b3d6198 100644 > --- a/target-arm/helper.c > +++ b/target-arm/helper.c > @@ -404,6 +404,8 @@ int32_t HELPER(sdiv)(int32_t num, int32_t den) > { > if (den == 0) > return 0; > + if (num == INT_MIN && den == -1) > + return INT_MIN; > return num / den; > } > > -- > 1.6.1.3 Acked-by: Laurent Desnogues <laurent.desnogues@gmail.com> That is provided we accept the behaviour for division by zero is not strictly conforming to what the ARM ARM says. Also note this instruction is not available on v7-A CPU's (Cortex-A8 for instance). It's part of v7-R (Cortex R4). Laurent
diff --git a/target-arm/helper.c b/target-arm/helper.c index 701629a..b3d6198 100644 --- a/target-arm/helper.c +++ b/target-arm/helper.c @@ -404,6 +404,8 @@ int32_t HELPER(sdiv)(int32_t num, int32_t den) { if (den == 0) return 0; + if (num == INT_MIN && den == -1) + return INT_MIN; return num / den; }
(INT32_MIN / -1) triggers an overflow, and the result depends on the host architecture (INT32_MIN on arm, -1 on ppc, SIGFPE on x86). Use a test to output the correct value. Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> --- target-arm/helper.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)