From 9be36fb8cb5bcdab5bbbc7a36388dc9a3d1cc397 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 26 Mar 2014 18:59:08 +0000 Subject: 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. --- sysdeps/x86_64/fpu/fegetenv.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'sysdeps/x86_64/fpu') diff --git a/sysdeps/x86_64/fpu/fegetenv.c b/sysdeps/x86_64/fpu/fegetenv.c index 364f917..0e0c269 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. */ -- cgit v1.1