diff options
Diffstat (limited to 'sysdeps/alpha/fpu/fesetenv.c')
-rw-r--r-- | sysdeps/alpha/fpu/fesetenv.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/sysdeps/alpha/fpu/fesetenv.c b/sysdeps/alpha/fpu/fesetenv.c new file mode 100644 index 0000000000..3692967a5b --- /dev/null +++ b/sysdeps/alpha/fpu/fesetenv.c @@ -0,0 +1,45 @@ +/* Install given floating-point environment. + Copyright (C) 1997 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.h> + +void +fesetenv (const fenv_t *envp) +{ + unsigned long 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)envp >= 0) + env = *envp; + else + env = (unsigned long)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 & ~(3UL << 58)) | (env & (3UL << 58)); + __asm__ __volatile__("mt_fpcr %0" : : "f"(fpcr)); + + /* Reset the exception status and mask with the kernel's FP code. */ + __ieee_set_fp_control(env & (FE_ALL_EXCEPT | 0x3e)); +} |