gcc/config/sparc/crtfastmath.c

   1 /*
   2  * Copyright (C) 2001 Free Software Foundation, Inc.
   3  * Contributed by David S. Miller (davem@redhat.com)
   4  *
   5  * This file is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2, or (at your option) any
   8  * later version.
   9  *
  10  * In addition to the permissions in the GNU General Public License, the
  11  * Free Software Foundation gives you unlimited permission to link the
  12  * compiled version of this file with other programs, and to distribute
  13  * those programs without any restriction coming from the use of this
  14  * file.  (The General Public License restrictions do apply in other
  15  * respects; for example, they cover modification of the file, and
  16  * distribution when not linked into another program.)
  17  *
  18  * This file is distributed in the hope that it will be useful, but
  19  * WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21  * General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; see the file COPYING.  If not, write to
  25  * the Free Software Foundation, 59 Temple Place - Suite 330,
  26  * Boston, MA 02111-1307, USA.
  27  *
  28  *    As a special exception, if you link this library with files
  29  *    compiled with GCC to produce an executable, this does not cause
  30  *    the resulting executable to be covered by the GNU General Public License.
  31  *    This exception does not however invalidate any other reasons why
  32  *    the executable file might be covered by the GNU General Public License.
  33  */
  34
  35 #define FPRS_NS         (1 << 22)       /* Non-Standard fpu results */
  36
  37 static void __attribute__((constructor))
  38 set_fast_math (void)
  39 {
  40   unsigned int fsr;
  41
  42   /* This works for the 64-bit case because, even if 32-bit ld/st of
  43      the fsr register modified the upper 32-bit, the only thing up there
  44      are the 3 other condition codes which are "do not care" at the time
  45      that this runs.  */
  46
  47   __asm__("st %%fsr, %0"
  48           : "=m" (fsr));
  49
  50   fsr |= FPRS_NS;
  51
  52   __asm__("ld %0, %%fsr"
  53           : : "m" (fsr));
  54 }