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| author | Joseph Myers <joseph@codesourcery.com> | 2015-11-05 21:56:31 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2015-11-05 21:56:31 +0000 |
| commit | 01189b083b8ce54fc568fd2ab0dd433d869ede0e (patch) | |
| tree | 15620545ab980f008bdec41540a43f1efea79ed0 /sysdeps/i386/i686 | |
| parent | 939fdd1c36dde8884543bc9c3b8506e76c9ff0e4 (diff) | |
| download | glibc-01189b083b8ce54fc568fd2ab0dd433d869ede0e.tar.gz | |
Fix i386/x86_64 log* (1) zero sign for -ffinite-math-only (bug 19213).
For the -ffinite-math-only versions of various x86_64 and x86 log*
functions, a zero result from log* (1) is returned with incorrect sign
in round-downward mode. This patch fixes this in a similar way to the
previous fixes for the non-*_finite versions of the functions.
Tested for x86_64 and x86 (including an i586 build), together with a
patch that will be applied separately to enable the main libm-test.inc
tests for the finite-math-only functions.
[BZ #19213]
* sysdeps/i386/fpu/e_log.S (__log_finite): Ensure +0 is always
returned for argument 1.
* sysdeps/i386/fpu/e_logf.S (__logf_finite): Likewise.
* sysdeps/i386/fpu/e_logl.S (__logl_finite): Likewise.
* sysdeps/i386/i686/fpu/e_logl.S (__logl_finite): Likewise.
* sysdeps/x86_64/fpu/e_log10l.S (__log10l_finite): Likewise.
* sysdeps/x86_64/fpu/e_log2l.S (__log2l_finite): Likewise.
* sysdeps/x86_64/fpu/e_logl.S (__logl_finite): Likewise.
Diffstat (limited to 'sysdeps/i386/i686')
| -rw-r--r-- | sysdeps/i386/i686/fpu/e_logl.S | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/sysdeps/i386/i686/fpu/e_logl.S b/sysdeps/i386/i686/fpu/e_logl.S index 0ccc8fc71e..e9ecbcd472 100644 --- a/sysdeps/i386/i686/fpu/e_logl.S +++ b/sysdeps/i386/i686/fpu/e_logl.S @@ -81,7 +81,13 @@ ENTRY(__logl_finite) fcomip %st(1) // |x-1| : x-1 : x : log(2) fstp %st(0) // x-1 : x : log(2) jc 2b - fstp %st(1) // x-1 : log(2) + fxam + fnstsw + andb $0x45, %ah + cmpb $0x40, %ah + jne 6f + fabs // log(1) is +0 in all rounding modes. +6: fstp %st(1) // x-1 : log(2) fyl2xp1 // log(x) ret END(__logl_finite) |