glibc/sysdeps/x86_64/fpu/fesetenv.c
Paul Eggert 581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00

115 lines
3.8 KiB
C

/* Install given floating-point environment.
Copyright (C) 2001-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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
<https://www.gnu.org/licenses/>. */
#include <fenv.h>
#include <fpu_control.h>
#include <assert.h>
/* All exceptions, including the x86-specific "denormal operand"
exception. */
#define FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM)
int
__fesetenv (const fenv_t *envp)
{
fenv_t temp;
/* Install the environment specified by ENVP. But there are a few
values which we do not want to come from the saved environment.
Therefore, we get the current environment and replace the values
we want to use from the environment specified by the parameter. */
__asm__ ("fnstenv %0\n"
"stmxcsr %1" : "=m" (*&temp), "=m" (*&temp.__mxcsr));
if (envp == FE_DFL_ENV)
{
temp.__control_word |= FE_ALL_EXCEPT_X86;
temp.__control_word &= ~FE_TOWARDZERO;
temp.__control_word |= _FPU_EXTENDED;
temp.__status_word &= ~FE_ALL_EXCEPT_X86;
temp.__eip = 0;
temp.__cs_selector = 0;
temp.__opcode = 0;
temp.__data_offset = 0;
temp.__data_selector = 0;
/* Clear SSE exceptions. */
temp.__mxcsr &= ~FE_ALL_EXCEPT_X86;
/* Set mask for SSE MXCSR. */
temp.__mxcsr |= (FE_ALL_EXCEPT_X86 << 7);
/* Set rounding to FE_TONEAREST. */
temp.__mxcsr &= ~ 0x6000;
temp.__mxcsr |= (FE_TONEAREST << 3);
/* Clear the FZ and DAZ bits. */
temp.__mxcsr &= ~0x8040;
}
else if (envp == FE_NOMASK_ENV)
{
temp.__control_word &= ~(FE_ALL_EXCEPT | FE_TOWARDZERO);
/* Keep the "denormal operand" exception masked. */
temp.__control_word |= __FE_DENORM;
temp.__control_word |= _FPU_EXTENDED;
temp.__status_word &= ~FE_ALL_EXCEPT_X86;
temp.__eip = 0;
temp.__cs_selector = 0;
temp.__opcode = 0;
temp.__data_offset = 0;
temp.__data_selector = 0;
/* Clear SSE exceptions. */
temp.__mxcsr &= ~FE_ALL_EXCEPT_X86;
/* Set mask for SSE MXCSR. */
/* Set rounding to FE_TONEAREST. */
temp.__mxcsr &= ~ 0x6000;
temp.__mxcsr |= (FE_TONEAREST << 3);
/* Do not mask exceptions. */
temp.__mxcsr &= ~(FE_ALL_EXCEPT << 7);
/* Keep the "denormal operand" exception masked. */
temp.__mxcsr |= (__FE_DENORM << 7);
/* Clear the FZ and DAZ bits. */
temp.__mxcsr &= ~0x8040;
}
else
{
temp.__control_word &= ~(FE_ALL_EXCEPT_X86
| FE_TOWARDZERO
| _FPU_EXTENDED);
temp.__control_word |= (envp->__control_word
& (FE_ALL_EXCEPT_X86
| FE_TOWARDZERO
| _FPU_EXTENDED));
temp.__status_word &= ~FE_ALL_EXCEPT_X86;
temp.__status_word |= envp->__status_word & FE_ALL_EXCEPT_X86;
temp.__eip = envp->__eip;
temp.__cs_selector = envp->__cs_selector;
temp.__opcode = envp->__opcode;
temp.__data_offset = envp->__data_offset;
temp.__data_selector = envp->__data_selector;
temp.__mxcsr = envp->__mxcsr;
}
__asm__ ("fldenv %0\n"
"ldmxcsr %1" : : "m" (temp), "m" (temp.__mxcsr));
/* Success. */
return 0;
}
libm_hidden_def (__fesetenv)
weak_alias (__fesetenv, fesetenv)
libm_hidden_weak (fesetenv)