diff options
Diffstat (limited to 'gcc/config/i386/crtprec.c')
-rw-r--r-- | gcc/config/i386/crtprec.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/gcc/config/i386/crtprec.c b/gcc/config/i386/crtprec.c new file mode 100644 index 00000000000..0c98b815233 --- /dev/null +++ b/gcc/config/i386/crtprec.c @@ -0,0 +1,57 @@ +/* + * Copyright (C) 2007 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 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, 51 Franklin Street, Fifth Floor, + * Boston, MA 02110-1301, 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. + */ + +#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)); +} |