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58 lines
2.1 KiB
C
58 lines
2.1 KiB
C
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/* Internal libc stuff for floating point environment routines.
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Copyright (C) 1997 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#ifndef _FENV_LIBC_H
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#define _FENV_LIBC_H 1
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#include <fenv.h>
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/* Transform a logical or of the FE_* bits to a bit pattern for the
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appropriate sticky bits in the FPSCR. */
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#define FE_to_sticky(excepts) \
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(-(excepts & FE_INVALID) & FE_ALL_INVALID \
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| (excepts) & (FE_ALL_EXCEPT & ~FE_INVALID | FE_ALL_INVALID))
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/* The sticky bits in the FPSCR indicating exceptions have occurred. */
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#define FPSCR_STICKY_BITS ((FE_ALL_EXCEPT | FE_ALL_INVALID) & ~FE_INVALID)
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/* Equivalent to fegetenv, but returns a fenv_t instead of taking a
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pointer. */
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#define fegetenv_register() \
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({ fenv_t env; asm ("mffs %0" : "=f" (env)); env; })
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/* Equivalent to fesetenv, but takes a fenv_t instead of a pointer. */
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#define fesetenv_register(env) \
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({ double d = (env); asm ("mtfsf 0xff,%0" : : "f" (d)); })
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/* This very handy macro:
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- Sets the rounding mode to 'round to nearest';
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- Sets the processor into IEEE mode; and
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- Prevents exceptions from being raised for inexact results.
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These things happen to be exactly what you need for typical elementary
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functions. */
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#define relax_fenv_state() asm ("mtfsfi 7,0")
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typedef union
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{
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fenv_t fenv;
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unsigned int l[2];
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} fenv_union_t;
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#endif /* fenv_libc.h */
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