Retro68/gcc/libgcc/config/i386/crtprec.c

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2012-03-27 23:13:14 +00:00
/*
* Copyright (C) 2007, 2009 Free Software Foundation, Inc.
*
* 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 3, or (at your option) any
* later version.
*
* 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.
*
* Under Section 7 of GPL version 3, you are granted additional
* permissions described in the GCC Runtime Library Exception, version
* 3.1, as published by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License and
* a copy of the GCC Runtime Library Exception along with this program;
* see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
* <http://www.gnu.org/licenses/>.
*/
#if __PREC == 32
#define X87CW (0 << 8) /* Single precision (24 bits) */
#elif __PREC == 64
#define X87CW (2 << 8) /* Double precision (53 bits) */
#elif __PREC == 80
#define X87CW (3 << 8) /* Extended precision (64 bits) */
#else
#error "Wrong precision requested."
#endif
#define X87CW_PCMASK (3 << 8)
static void __attribute__((constructor))
set_precision (void)
{
unsigned short int cwd;
asm volatile ("fstcw\t%0" : "=m" (cwd));
cwd &= ~X87CW_PCMASK;
cwd |= X87CW;
asm volatile ("fldcw\t%0" : : "m" (cwd));
}