fpu_control.h
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/* FPU control word bits. Mips version.
Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Olaf Flebbe and Ralf Baechle.
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. */
#ifndef _FPU_CONTROL_H
#define _FPU_CONTROL_H
/* MIPS FPU floating point control register bits.
*
* 31-25 -> floating point conditions code bits 7-1. These bits are only
* available in MIPS IV.
* 24 -> flush denormalized results to zero instead of
* causing unimplemented operation exception. This bit is only
* available for MIPS III and newer.
* 23 -> Condition bit
* 22-18 -> reserved (read as 0, write with 0)
* 17 -> cause bit for unimplemented operation
* 16 -> cause bit for invalid exception
* 15 -> cause bit for division by zero exception
* 14 -> cause bit for overflow exception
* 13 -> cause bit for underflow exception
* 12 -> cause bit for inexact exception
* 11 -> enable exception for invalid exception
* 10 -> enable exception for division by zero exception
* 9 -> enable exception for overflow exception
* 8 -> enable exception for underflow exception
* 7 -> enable exception for inexact exception
* 6 -> flag invalid exception
* 5 -> flag division by zero exception
* 4 -> flag overflow exception
* 3 -> flag underflow exception
* 2 -> flag inexact exception
* 1-0 -> rounding control
*
*
* Rounding Control:
* 00 - rounding to nearest (RN)
* 01 - rounding toward zero (RZ)
* 10 - rounding (up) toward plus infinity (RP)
* 11 - rounding (down)toward minus infinity (RM)
*/
#include <features.h>
/* masking of interrupts */
#define _FPU_MASK_V 0x0800 /* Invalid operation */
#define _FPU_MASK_Z 0x0400 /* Division by zero */
#define _FPU_MASK_O 0x0200 /* Overflow */
#define _FPU_MASK_U 0x0100 /* Underflow */
#define _FPU_MASK_I 0x0080 /* Inexact operation */
/* flush denormalized numbers to zero */
#define _FPU_FLUSH_TZ 0x1000000
/* rounding control */
#define _FPU_RC_NEAREST 0x0 /* RECOMMENDED */
#define _FPU_RC_ZERO 0x1
#define _FPU_RC_UP 0x2
#define _FPU_RC_DOWN 0x3
#define _FPU_RESERVED 0xfe3c0000 /* Reserved bits in cw */
/* The fdlibm code requires strict IEEE double precision arithmetic,
and no interrupts for exceptions, rounding to nearest. */
#define _FPU_DEFAULT 0x00000000
/* IEEE: same as above, but exceptions */
#define _FPU_IEEE 0x00000F80
/* Type of the control word. */
typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__HI__)));
/* Macros for accessing the hardware control word. */
#define _FPU_GETCW(cw) __asm__ ("cfc1 %0,$31" : "=r" (cw) : )
#define _FPU_SETCW(cw) __asm__ ("ctc1 %0,$31" : : "r" (cw))
/* Default control word set at startup. */
extern fpu_control_t __fpu_control;
#endif /* fpu_control.h */