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