mirror of
git://sourceware.org/git/glibc.git
synced 2024-12-09 04:11:27 +08:00
101 lines
2.8 KiB
C
101 lines
2.8 KiB
C
|
/* Copyright (C) 1993 Free Software Foundation, Inc.
|
||
|
This file is part of the GNU C Library.
|
||
|
Contributed by Olaf Flebbe.
|
||
|
|
||
|
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
|
||
|
|
||
|
/* Here is the dirty part. Settup up your 387 through the control word
|
||
|
* (cw) register.
|
||
|
*
|
||
|
* 15-13 12 11-10 9-8 7-6 5 4 3 2 1 0
|
||
|
* | reserved | IC | RC | PC | reserved | PM | UM | OM | ZM | DM | IM
|
||
|
*
|
||
|
* IM: Invalid operation mask
|
||
|
* DM: Denormalized operand mask
|
||
|
* ZM: Zero-divide mask
|
||
|
* OM: Overflow mask
|
||
|
* UM: Underflow mask
|
||
|
* PM: Precision (inexact result) mask
|
||
|
*
|
||
|
* Mask bit is 1 means no interrupt.
|
||
|
*
|
||
|
* PC: Precision control
|
||
|
* 11 - round to extended precision
|
||
|
* 10 - round to double precision
|
||
|
* 00 - round to single precision
|
||
|
*
|
||
|
* RC: Rounding control
|
||
|
* 00 - rounding to nearest
|
||
|
* 01 - rounding down (toward - infinity)
|
||
|
* 10 - rounding up (toward + infinity)
|
||
|
* 11 - rounding toward zero
|
||
|
*
|
||
|
* IC: Infinity control
|
||
|
* That is for 8087 and 80287 only.
|
||
|
*
|
||
|
* The hardware default is 0x037f. I choose 0x1372.
|
||
|
*/
|
||
|
|
||
|
#include <features.h>
|
||
|
|
||
|
/* masking of interrupts */
|
||
|
#define _FPU_MASK_IM 0x01
|
||
|
#define _FPU_MASK_DM 0x02
|
||
|
#define _FPU_MASK_ZM 0x04
|
||
|
#define _FPU_MASK_OM 0x08
|
||
|
#define _FPU_MASK_UM 0x10
|
||
|
#define _FPU_MASK_PM 0x20
|
||
|
|
||
|
/* precision control */
|
||
|
#define _FPU_EXTENDED 0x300 /* RECOMMENDED */
|
||
|
#define _FPU_DOUBLE 0x200
|
||
|
#define _FPU_SINGLE 0x0 /* DO NOT USE */
|
||
|
|
||
|
/* rounding control */
|
||
|
#define _FPU_RC_NEAREST 0x0 /* RECOMMENDED */
|
||
|
#define _FPU_RC_DOWN 0x400
|
||
|
#define _FPU_RC_UP 0x800
|
||
|
#define _FPU_RC_ZERO 0xC00
|
||
|
|
||
|
#define _FPU_RESERVED 0xF0C0 /* Reserved bits in cw */
|
||
|
|
||
|
|
||
|
/* Now two recommended cw */
|
||
|
|
||
|
/* Linux default:
|
||
|
- extended precision
|
||
|
- rounding to nearest
|
||
|
- exceptions on overflow, zero divide and NaN */
|
||
|
#define _FPU_DEFAULT 0x1372
|
||
|
|
||
|
/* IEEE: same as above, but exceptions */
|
||
|
#define _FPU_IEEE 0x137f
|
||
|
|
||
|
/* private namespace. It should only be used in init-first.o. */
|
||
|
extern unsigned short __fpu_control;
|
||
|
|
||
|
__BEGIN_DECLS
|
||
|
|
||
|
/* called in init-first.o. It can be used to manipulate 387 control word. */
|
||
|
extern void __setfpucw __P ((unsigned short));
|
||
|
|
||
|
__END_DECLS
|
||
|
|
||
|
#endif /* fpu_control.h */
|