glibc/sysdeps/i386/fpu/fegetenv.c
Joseph Myers 77d08acaad Include SSE state in i386 fenv_t (bug 16064).
This patch fixes bug 16064, i386 fenv_t not including SSE state, using
the technique suggested there of storing the state in the existing
__eip field of fenv_t to avoid needing to increase the size of fenv_t
and add new symbol versions.  The included testcase, which previously
failed for i386 (but passed for x86_64), illustrates how the previous
state was buggy.

This patch causes the SSE state to be included *to the extent it is on
x86_64*.  Where some state should logically be included but isn't for
x86_64 (see bug 16068), this patch does not cause it to be included
for i386 either.  The idea is that any patch fixing that bug should
fix it for both x86_64 and i386 at once.

Tested i386 and x86_64.  (I haven't tested the case of a CPU without
SSE2 disabling the test.)

	[BZ #16064]
	* sysdeps/i386/fpu/fegetenv.c: Include <unistd.h>, <ldsodefs.h>
	and <dl-procinfo.h>.
	(__fegetenv): Save SSE state in envp->__eip if supported.
	* sysdeps/i386/fpu/feholdexcpt.c (feholdexcept): Save SSE state in
	envp->__eip if supported.
	* sysdeps/i386/fpu/fesetenv.c: Include <unistd.h>, <ldsodefs.h>
	and <dl-procinfo.h>.
	(__fesetenv): Always set __eip, __cs_selector, __opcode,
	__data_offset and __data_selector in environment to 0.  Set SSE
	state if supported.
	* sysdeps/x86/fpu/Makefile [$(subdir) = math] (tests): Add
	test-fenv-sse.
	[$(subdir) = math] (CFLAGS-test-fenv-sse.c): Add -msse2
	-mfpmath=sse.
	* sysdeps/x86/fpu/test-fenv-sse.c: New file.
2014-05-09 16:59:56 +00:00

49 lines
1.6 KiB
C

/* Store current floating-point environment.
Copyright (C) 1997-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <fenv.h>
#include <unistd.h>
#include <ldsodefs.h>
#include <dl-procinfo.h>
int
__fegetenv (fenv_t *envp)
{
__asm__ ("fnstenv %0" : "=m" (*envp));
/* And load it right back since the processor changes the mask.
Intel thought this opcode to be used in interrupt handlers which
would block all exceptions. */
__asm__ ("fldenv %0" : : "m" (*envp));
if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
__asm__ ("stmxcsr %0" : "=m" (envp->__eip));
/* Success. */
return 0;
}
#include <shlib-compat.h>
#if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
strong_alias (__fegetenv, __old_fegetenv)
compat_symbol (libm, __old_fegetenv, fegetenv, GLIBC_2_1);
#endif
libm_hidden_ver (__fegetenv, fegetenv)
versioned_symbol (libm, __fegetenv, fegetenv, GLIBC_2_2);