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/* 68k FPU control word definitions.
Copyright (C) 1996-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<https://www.gnu.org/licenses/>. */
#ifndef _FPU_CONTROL_H
#define _FPU_CONTROL_H
/*
* Motorola floating point control register bits.
*
* 31-16 -> reserved (read as 0, ignored on write)
* 15 -> enable trap for BSUN exception
* 14 -> enable trap for SNAN exception
* 13 -> enable trap for OPERR exception
* 12 -> enable trap for OVFL exception
* 11 -> enable trap for UNFL exception
* 10 -> enable trap for DZ exception
* 9 -> enable trap for INEX2 exception (INEX on Coldfire)
* 8 -> enable trap for INEX1 exception (IDE on Coldfire)
* 7-6 -> Precision Control (only bit 6 is used on Coldfire)
* 5-4 -> Rounding Control
* 3-0 -> zero (read as 0, write as 0)
*
*
* Precision Control:
* 00 - round to extended precision
* 01 - round to single precision
* 10 - round to double precision
* 11 - undefined
*
* Rounding Control:
* 00 - rounding to nearest (RN)
* 01 - rounding toward zero (RZ)
* 10 - rounding (down)toward minus infinity (RM)
* 11 - rounding (up) toward plus infinity (RP)
*
* The hardware default is 0x0000. I choose 0x5400.
*/
#include <features.h>
#if defined (__mcoldfire__) && !defined (__mcffpu__)
# define _FPU_RESERVED 0xffffffff
# define _FPU_DEFAULT 0x00000000
# define _FPU_GETCW(cw) ((cw) = 0)
# define _FPU_SETCW(cw) ((void) (cw))
#else
/* masking of interrupts */
# define _FPU_MASK_BSUN 0x8000
# define _FPU_MASK_SNAN 0x4000
# define _FPU_MASK_OPERR 0x2000
# define _FPU_MASK_OVFL 0x1000
# define _FPU_MASK_UNFL 0x0800
# define _FPU_MASK_DZ 0x0400
# define _FPU_MASK_INEX1 0x0200
# define _FPU_MASK_INEX2 0x0100
/* precision control */
# ifdef __mcoldfire__
# define _FPU_DOUBLE 0x00
# else
# define _FPU_EXTENDED 0x00 /* RECOMMENDED */
# define _FPU_DOUBLE 0x80
# endif
# define _FPU_SINGLE 0x40 /* DO NOT USE */
/* rounding control */
# define _FPU_RC_NEAREST 0x00 /* RECOMMENDED */
# define _FPU_RC_ZERO 0x10
# define _FPU_RC_DOWN 0x20
# define _FPU_RC_UP 0x30
# ifdef __mcoldfire__
# define _FPU_RESERVED 0xFFFF800F
# else
# define _FPU_RESERVED 0xFFFF000F /* Reserved bits in fpucr */
# endif
/* Now two recommended fpucr */
/* The fdlibm code requires no interrupts for exceptions. Don't
change the rounding mode, it would break long double I/O! */
# define _FPU_DEFAULT 0x00000000
/* IEEE: same as above, but exceptions. We must make it non-zero so
that __setfpucw works. This bit will be ignored. */
# define _FPU_IEEE 0x00000001
/* Macros for accessing the hardware control word. */
# define _FPU_GETCW(cw) __asm__ ("fmove%.l %!, %0" : "=dm" (cw))
# define _FPU_SETCW(cw) __asm__ volatile ("fmove%.l %0, %!" : : "dm" (cw))
#endif
/* Type of the control word. */
typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__)));
/* Default control word set at startup. */
extern fpu_control_t __fpu_control;
#endif /* _M68K_FPU_CONTROL_H */
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