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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2015-12-17 12:34:57 -0200 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2015-12-17 14:34:33 -0200 |
| commit | 2094350c9c9c1b87cf34b193ad6541e4a29b62dc (patch) | |
| tree | dd5053ee8aba5d47b33dff0e21bfcfd18436237b | |
| parent | d29d57eed9a6acb646663a02b7eb2bece2c433dc (diff) | |
| download | glibc-2094350c9c9c1b87cf34b193ad6541e4a29b62dc.tar.gz | |
Fix POWER7 logb results for negative subnormals (bug 19375)
The optimized POWER7 logb implementation does not use the absolute
value of the word extracted from the input to apply the leading 0-bits
builtin (to ignore the float sign). This patch fixes it by
clearing the signal bit in the resulting word.
It fixes the subnormal tests failures when running on POWER7 ou
newer chip.
Tested on powerpc64le (POWER8).
[BZ# 19375]
* sysdeps/powerpc/power7/fpu/s_logb.c (__logb): Fix return for
negative subnormals.
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | sysdeps/powerpc/power7/fpu/s_logb.c | 1 |
2 files changed, 6 insertions, 0 deletions
@@ -1,3 +1,8 @@ +2015-12-17 Adhemerval Zanella <adhemerval.zanella@linaro.org> + + * sysdeps/powerpc/power7/fpu/s_logb.c (__logb): Fix return for + negative subnormals. + 2015-12-16 H.J. Lu <hongjiu.lu@intel.com> * sysdeps/unix/sysv/linux/x86_64/sysdep.h diff --git a/sysdeps/powerpc/power7/fpu/s_logb.c b/sysdeps/powerpc/power7/fpu/s_logb.c index c5feb67960..abd1c2ae3c 100644 --- a/sysdeps/powerpc/power7/fpu/s_logb.c +++ b/sysdeps/powerpc/power7/fpu/s_logb.c @@ -58,6 +58,7 @@ __logb (double x) int ma; EXTRACT_WORDS (ix, lx, x); + ix &= 0x7fffffff; if (ix == 0) ma = __builtin_clz (lx) + 32; else |