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authorJoseph Myers <joseph@codesourcery.com>2014-03-26 18:59:08 +0000
committerJoseph Myers <joseph@codesourcery.com>2014-03-26 18:59:08 +0000
commit9be36fb8cb5bcdab5bbbc7a36388dc9a3d1cc397 (patch)
tree2cc35309dc7cb65fbe9f8fe46762edf8a50a7f02 /sysdeps/x86_64
parent60a2f3c166cebf56048d00cee47b9ed1969844d6 (diff)
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Make x86_64 fegetenv preserve exception mask (bug 16198).
Bug 16198 is x86_64 fegetenv wrongly masking exceptions for which traps are enabled, because that's a side-effect of the fnstenv instruction. This patch fixes it to use fldenv immediately after fnstenv, like the i386 version. Tested x86_64 and x86. [BZ #16198] * sysdeps/x86_64/fpu/fegetenv.c (fegetenv): Use fldenv after fnstenv. * math/test-fenv-preserve.c: New file. * math/Makefile (tests): Add test-fenv-preserve.
Diffstat (limited to 'sysdeps/x86_64')
-rw-r--r--sysdeps/x86_64/fpu/fegetenv.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/sysdeps/x86_64/fpu/fegetenv.c b/sysdeps/x86_64/fpu/fegetenv.c
index 364f917719..0e0c269375 100644
--- a/sysdeps/x86_64/fpu/fegetenv.c
+++ b/sysdeps/x86_64/fpu/fegetenv.c
@@ -22,6 +22,9 @@ int
fegetenv (fenv_t *envp)
{
__asm__ ("fnstenv %0\n"
+ /* fnstenv changes the exception mask, so load back the
+ stored environment. */
+ "fldenv %0\n"
"stmxcsr %1" : "=m" (*envp), "=m" (envp->__mxcsr));
/* Success. */