aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/x86_64
diff options
context:
space:
mode:
authorJoseph Myers <joseph@codesourcery.com>2015-11-05 21:56:31 +0000
committerJoseph Myers <joseph@codesourcery.com>2015-11-05 21:56:31 +0000
commit01189b083b8ce54fc568fd2ab0dd433d869ede0e (patch)
tree15620545ab980f008bdec41540a43f1efea79ed0 /sysdeps/x86_64
parent939fdd1c36dde8884543bc9c3b8506e76c9ff0e4 (diff)
downloadglibc-01189b083b8ce54fc568fd2ab0dd433d869ede0e.zip
glibc-01189b083b8ce54fc568fd2ab0dd433d869ede0e.tar.gz
glibc-01189b083b8ce54fc568fd2ab0dd433d869ede0e.tar.bz2
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/x86_64')
-rw-r--r--sysdeps/x86_64/fpu/e_log10l.S8
-rw-r--r--sysdeps/x86_64/fpu/e_log2l.S8
-rw-r--r--sysdeps/x86_64/fpu/e_logl.S8
3 files changed, 21 insertions, 3 deletions
diff --git a/sysdeps/x86_64/fpu/e_log10l.S b/sysdeps/x86_64/fpu/e_log10l.S
index 2607ad1..8fa6164 100644
--- a/sysdeps/x86_64/fpu/e_log10l.S
+++ b/sysdeps/x86_64/fpu/e_log10l.S
@@ -79,7 +79,13 @@ ENTRY(__log10l_finite)
fnstsw // x-1 : x : log10(2)
andb $0x45, %ah
jz 2b
- fstp %st(1) // x-1 : log10(2)
+ fxam
+ fnstsw
+ andb $0x45, %ah
+ cmpb $0x40, %ah
+ jne 6f
+ fabs // log10(1) is +0 in all rounding modes.
+6: fstp %st(1) // x-1 : log10(2)
fyl2xp1 // log10(x)
ret
END(__log10l_finite)
diff --git a/sysdeps/x86_64/fpu/e_log2l.S b/sysdeps/x86_64/fpu/e_log2l.S
index c12906d..a063255 100644
--- a/sysdeps/x86_64/fpu/e_log2l.S
+++ b/sysdeps/x86_64/fpu/e_log2l.S
@@ -78,7 +78,13 @@ ENTRY(__log2l_finite)
fnstsw // x-1 : x : 1
andb $0x45, %ah
jz 2b
- fstp %st(1) // x-1 : 1
+ fxam
+ fnstsw
+ andb $0x45, %ah
+ cmpb $0x40, %ah
+ jne 6f
+ fabs // log2(1) is +0 in all rounding modes.
+6: fstp %st(1) // x-1 : 1
fyl2xp1 // log(x)
ret
END (__log2l_finite)
diff --git a/sysdeps/x86_64/fpu/e_logl.S b/sysdeps/x86_64/fpu/e_logl.S
index 047b8db..dbe6fd5 100644
--- a/sysdeps/x86_64/fpu/e_logl.S
+++ b/sysdeps/x86_64/fpu/e_logl.S
@@ -81,7 +81,13 @@ ENTRY(__logl_finite)
fnstsw // x-1 : x : log(2)
andb $0x45, %ah
jz 2b
- fstp %st(1) // x-1 : log(2)
+ fxam
+ fnstsw
+ andb $0x45, %ah
+ cmpb $0x40, %ah
+ jne 7f
+ fabs // log(1) is +0 in all rounding modes.
+7: fstp %st(1) // x-1 : log(2)
fyl2xp1 // log(x)
ret
END (__logl_finite)