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git.ipfire.org Git - thirdparty/glibc.git/blob - sysdeps/i386/fpu/fesetmode.c
1 /* Install given floating-point control modes. i386 version.
2 Copyright (C) 2016-2019 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
20 #include <fpu_control.h>
23 #include <dl-procinfo.h>
25 /* All exceptions, including the x86-specific "denormal operand"
27 #define FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM)
30 fesetmode (const femode_t
*modep
)
33 if (modep
== FE_DFL_MODE
)
36 cw
= modep
->__control_word
;
38 if (HAS_CPU_FEATURE (SSE
))
41 __asm__ ("stmxcsr %0" : "=m" (mxcsr
));
42 /* Preserve SSE exception flags but restore other state in
44 mxcsr
&= FE_ALL_EXCEPT_X86
;
45 if (modep
== FE_DFL_MODE
)
46 /* Default MXCSR state has all bits zero except for those
47 masking exceptions. */
48 mxcsr
|= FE_ALL_EXCEPT_X86
<< 7;
50 mxcsr
|= modep
->__mxcsr
& ~FE_ALL_EXCEPT_X86
;
51 __asm__ ("ldmxcsr %0" : : "m" (mxcsr
));