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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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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 _FPU_CONTROL_H
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#define _FPU_CONTROL_H
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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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#include <features.h>
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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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/* flush denormalized numbers to zero */
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#define _FPU_FLUSH_TZ 0x1000000
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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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#define _FPU_RESERVED 0xfe3c0000 /* Reserved bits in cw */
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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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#define _FPU_DEFAULT 0x00000000
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/* IEEE: same as above, but exceptions */
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#define _FPU_IEEE 0x00000F80
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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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/* 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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/* Default control word set at startup. */
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extern fpu_control_t __fpu_control;
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#endif /* fpu_control.h */
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