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/* Copyright (C) 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson <rth@tamu.edu>, 1997
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* This file should never be included directly. */
#ifndef _FENVBITS_H
#define _FENVBITS_H 1
/* Define the bits representing the exception.
Note that these are the bit positions as defined by the OSF/1
ieee_{get,set}_control_word interface and not by the hardware fpcr.
See the Alpha Architecture Handbook section 4.7.7.3 for details,
but in summary, trap shadows mean the hardware register can acquire
extra exception bits so for proper IEEE support the tracking has to
be done in software -- in this case with kernel support.
As to why the system call interface isn't in the same format as
the hardware register, only those crazy folks at DEC can tell you. */
enum
{
FE_INEXACT = 1UL << 21,
#define FE_INEXACT FE_INEXACT
FE_UNDERFLOW = 1UL << 20,
#define FE_UNDERFLOW FE_UNDERFLOW
FE_OVERFLOW = 1UL << 19,
#define FE_OVERFLOW FE_OVERFLOW
FE_DIVBYZERO = 1UL << 18,
#define FE_DIVBYZERO FE_DIVBYZERO
FE_INVALID = 1UL << 17,
#define FE_INVALID FE_INVALID
FE_ALL_EXCEPT =
(FE_INEXACT | FE_DIVBYZERO | FE_UNDERFLOW | FE_OVERFLOW | FE_INVALID)
#define FE_ALL_EXCEPT FE_ALL_EXCEPT
};
/* Alpha chips support all four defined rouding modes.
Note that code must be compiled to use dynamic rounding (/d) instructions
to see these changes. For gcc this is -mfp-rounding-mode=d; for DEC cc
this is -fprm d. The default for both is static rounding to nearest.
These are shifted down 58 bits from the hardware fpcr because the
functions are declared to take integers. */
enum
{
FE_TOWARDSZERO = 0,
#define FE_TOWARDSZERO FE_TOWARDSZERO
FE_DOWNWARD = 1,
#define FE_DOWNWARD FE_DOWNWARD
FE_TONEAREST = 2,
#define FE_TONEAREST FE_TONEAREST
FE_UPWARD = 3,
#define FE_UPWARD FE_UPWARD
};
/* Type representing exception flags. */
typedef unsigned long fexcept_t;
/* Type representing floating-point environment. */
typedef unsigned long fenv_t;
/* If the default argument is used we use this value. Note that due to
architecture-specified page mappings, no user-space pointer will ever
have its two high bits set. Co-opt one. */
#define FE_DFL_ENV ((fenv_t *) 0x8800000000000000UL)
#ifdef __USE_GNU
/* Floating-point environment where none of the exceptions are masked. */
# define FE_NOMASK_ENV ((fenv_t *) 0x880000000000003eUL)
#endif
/* The system calls to talk to the kernel's FP code. */
extern unsigned long __ieee_get_fp_control(void);
extern void __ieee_set_fp_control(unsigned long);
#endif /* fenvbits.h */
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