glibc/sysdeps/alpha/fpu/fesetenv.c
2000-08-19 16:07:37 +00:00

52 lines
2.0 KiB
C

/* Install given floating-point environment.
Copyright (C) 1997, 1999, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson <rth@tamu.edu>, 1997
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <fenv_libc.h>
int
__fesetenv (const fenv_t *envp)
{
unsigned long int fpcr;
fenv_t env;
/* Magic encoding of default values: high bit set (never possible for a
user-space address) is not indirect. And we don't even have to get
rid of it since we mask things around just below. */
if ((long int) envp >= 0)
env = *envp;
else
env = (unsigned long int) envp;
/* Reset the rounding mode with the hardware fpcr. Note that the following
system call is an implied trap barrier for our modification. */
__asm__ __volatile__ ("excb; mf_fpcr %0" : "=f" (fpcr));
fpcr = (fpcr & ~FPCR_ROUND_MASK) | (env & FPCR_ROUND_MASK);
__asm__ __volatile__ ("mt_fpcr %0" : : "f" (fpcr));
/* Reset the exception status and mask with the kernel's FP code. */
__ieee_set_fp_control (env & SWCR_ALL_MASK);
/* Success. */
return 0;
}
strong_alias (__fesetenv, __old_fesetenv)
symbol_version (__old_fesetenv, fesetenv, GLIBC_2.1);
default_symbol_version (__fesetenv, fesetenv, GLIBC_2.2);