powerpc: Fix llround spurious inexact on 32-bit POWER4 [BZ #22697]
Commit Message
This issue is similar to BZ #19235, where spurious exceptions are
created from adding 0.5 then converting to an integer.
The solution is based on Joseph's fix for BZ #19235.
2018-01-10 Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
[BZ #22697]
* sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S (__llround):
Do not add 0.5 to integer or out-of-range arguments.
---
sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S | 5 +++++
1 file changed, 5 insertions(+)
Comments
On 01/11/2018 04:20 AM, Tulio Magno Quites Machado Filho wrote:
> This issue is similar to BZ #19235, where spurious exceptions are
> created from adding 0.5 then converting to an integer.
> The solution is based on Joseph's fix for BZ #19235.
>
> 2018-01-10 Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
>
> [BZ #22697]
> * sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S (__llround):
> Do not add 0.5 to integer or out-of-range arguments.
LGTM
>
Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com> writes:
> On 01/11/2018 04:20 AM, Tulio Magno Quites Machado Filho wrote:
>> This issue is similar to BZ #19235, where spurious exceptions are
>> created from adding 0.5 then converting to an integer.
>> The solution is based on Joseph's fix for BZ #19235.
>>
>> 2018-01-10 Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
>>
>> [BZ #22697]
>> * sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S (__llround):
>> Do not add 0.5 to integer or out-of-range arguments.
>
>
> LGTM
Pushed as af1e6be4ba60.
Thanks!
@@ -71,6 +71,11 @@ ENTRY (__llround)
fcmpu cr1,fp1,fp12 /* x is negative? x < 0.0 */
blt- cr6,.Lretzero /* 0.5 > x < -0.5 so just return 0. */
bge- cr7,.Lnobias /* 2^52 > x < -2^52 just convert with no bias. */
+ /* Test whether an integer to avoid spurious "inexact". */
+ fadd fp3,fp2,fp9
+ fsub fp3,fp3,fp9
+ fcmpu cr5,fp2,fp3
+ beq cr5,.Lnobias
fadd fp3,fp2,fp10 /* |x|+=0.5 bias to prepare to round. */
bge cr1,.Lconvert /* x is positive so don't negate x. */
fnabs fp3,fp3 /* -(|x|+=0.5) */