fenvinline.h

来自「它通过提供glibc兼容使得应用程序移植到较小的c 库时相当得容易. 它能够应用」· C头文件 代码 · 共 60 行

/* Inline floating-point environment handling functions for powerpc.
   Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#if defined __GNUC__ && !defined _SOFT_FLOAT && !defined __NO_MATH_INLINES

/* Inline definition for fegetround.  */
# define fegetround() \
  (__extension__  ({ int __fegetround_result;				      \
		     __asm__ ("mcrfs 7,7 ; mfcr %0"			      \
			     : "=r"(__fegetround_result) : : "cr7");	      \
		     __fegetround_result & 3; }))

/* The weird 'i#*X' constraints on the following suppress a gcc
   warning when __excepts is not a constant.  Otherwise, they mean the
   same as just plain 'i'.  */

/* Inline definition for feraiseexcept.  */
# define feraiseexcept(__excepts) \
  ((__builtin_constant_p (__excepts)					      \
    && ((__excepts) & ((__excepts)-1)) == 0				      \
    && (__excepts) != FE_INVALID)					      \
   ? ((__excepts) != 0							      \
      ? (__extension__ ({ __asm__ __volatile__				      \
			  ("mtfsb1 %s0"					      \
			   : : "i#*X"(__builtin_ffs (__excepts)));	      \
			  0; }))					      \
      : 0)								      \
   : (feraiseexcept) (__excepts))

/* Inline definition for feclearexcept.  */
# define feclearexcept(__excepts) \
  ((__builtin_constant_p (__excepts)					      \
    && ((__excepts) & ((__excepts)-1)) == 0				      \
    && (__excepts) != FE_INVALID)					      \
   ? ((__excepts) != 0							      \
      ? (__extension__ ({ __asm__ __volatile__				      \
			  ("mtfsb0 %s0"					      \
			   : : "i#*X"(__builtin_ffs (__excepts)));	      \
			  0; }))					      \
      : 0)								      \
   : (feclearexcept) (__excepts))

#endif /* __GNUC__ && !_SOFT_FLOAT */