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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
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')
-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.  */