crtfastmath.c

linux下的gcc编译器

/*
 * Copyright (C) 2001 Free Software Foundation, Inc.
 * Contributed by Richard Henderson ([e-mail])
 *
 * This file is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 * 
 * In addition to the permissions in the GNU General Public License, the
 * Free Software Foundation gives you unlimited permission to link the
 * compiled version of this file with other programs, and to distribute
 * those programs without any restriction coming from the use of this
 * file.  (The General Public License restrictions do apply in other
 * respects; for example, they cover modification of the file, and
 * distribution when not linked into another program.)
 * 
 * This file 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
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 * 
 *    As a special exception, if you link this library with files
 *    compiled with GCC to produce an executable, this does not cause
 *    the resulting executable to be covered by the GNU General Public License.
 *    This exception does not however invalidate any other reasons why
 *    the executable file might be covered by the GNU General Public License.
 */

/* Assume OSF/1 compatible interfaces.  */

extern void __ieee_set_fp_control (unsigned long int);

#define IEEE_MAP_DMZ  (1UL<<12)       /* Map denorm inputs to zero */
#define IEEE_MAP_UMZ  (1UL<<13)       /* Map underflowed outputs to zero */

static void __attribute__((constructor))
set_fast_math (void)
{
  __ieee_set_fp_control (IEEE_MAP_DMZ | IEEE_MAP_UMZ);
}