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      1 /*-
      2  * Copyright (c) 2004-2005 David Schultz <das (at) FreeBSD.ORG>
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     24  * SUCH DAMAGE.
     25  *
     26  * $FreeBSD: src/lib/msun/powerpc/fenv.h,v 1.3 2005/03/16 19:03:45 das Exp $
     27  */
     28 
     29 #ifndef	_FENV_H_
     30 #define	_FENV_H_
     31 
     32 #include <sys/_types.h>
     33 
     34 typedef	__uint32_t	fenv_t;
     35 typedef	__uint32_t	fexcept_t;
     36 
     37 /* Exception flags */
     38 #define	FE_INEXACT	0x02000000
     39 #define	FE_DIVBYZERO	0x04000000
     40 #define	FE_UNDERFLOW	0x08000000
     41 #define	FE_OVERFLOW	0x10000000
     42 #define	FE_INVALID	0x20000000	/* all types of invalid FP ops */
     43 
     44 /*
     45  * The PowerPC architecture has extra invalid flags that indicate the
     46  * specific type of invalid operation occurred.  These flags may be
     47  * tested, set, and cleared---but not masked---separately.  All of
     48  * these bits are cleared when FE_INVALID is cleared, but only
     49  * FE_VXSOFT is set when FE_INVALID is explicitly set in software.
     50  */
     51 #define	FE_VXCVI	0x00000100	/* invalid integer convert */
     52 #define	FE_VXSQRT	0x00000200	/* square root of a negative */
     53 #define	FE_VXSOFT	0x00000400	/* software-requested exception */
     54 #define	FE_VXVC		0x00080000	/* ordered comparison involving NaN */
     55 #define	FE_VXIMZ	0x00100000	/* inf * 0 */
     56 #define	FE_VXZDZ	0x00200000	/* 0 / 0 */
     57 #define	FE_VXIDI	0x00400000	/* inf / inf */
     58 #define	FE_VXISI	0x00800000	/* inf - inf */
     59 #define	FE_VXSNAN	0x01000000	/* operation on a signalling NaN */
     60 #define	FE_ALL_INVALID	(FE_VXCVI | FE_VXSQRT | FE_VXSOFT | FE_VXVC | \
     61 			 FE_VXIMZ | FE_VXZDZ | FE_VXIDI | FE_VXISI | \
     62 			 FE_VXSNAN | FE_INVALID)
     63 #define	FE_ALL_EXCEPT	(FE_DIVBYZERO | FE_INEXACT | \
     64 			 FE_ALL_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
     65 
     66 /* Rounding modes */
     67 #define	FE_TONEAREST	0x0000
     68 #define	FE_TOWARDZERO	0x0001
     69 #define	FE_UPWARD	0x0002
     70 #define	FE_DOWNWARD	0x0003
     71 #define	_ROUND_MASK	(FE_TONEAREST | FE_DOWNWARD | \
     72 			 FE_UPWARD | FE_TOWARDZERO)
     73 
     74 __BEGIN_DECLS
     75 
     76 /* Default floating-point environment */
     77 extern const fenv_t	__fe_dfl_env;
     78 #define	FE_DFL_ENV	(&__fe_dfl_env)
     79 
     80 /* We need to be able to map status flag positions to mask flag positions */
     81 #define	_FPUSW_SHIFT	22
     82 #define	_ENABLE_MASK	((FE_DIVBYZERO | FE_INEXACT | FE_INVALID | \
     83 			 FE_OVERFLOW | FE_UNDERFLOW) >> _FPUSW_SHIFT)
     84 
     85 #define	__mffs(__env)	__asm __volatile("mffs %0" : "=f" (*(__env)))
     86 #define	__mtfsf(__env)	__asm __volatile("mtfsf 255,%0" : : "f" (__env))
     87 
     88 union __fpscr {
     89 	double __d;
     90 	struct {
     91 		__uint32_t __junk;
     92 		fenv_t __reg;
     93 	} __bits;
     94 };
     95 
     96 static __inline int
     97 feclearexcept(int __excepts)
     98 {
     99 	union __fpscr __r;
    100 
    101 	if (__excepts & FE_INVALID)
    102 		__excepts |= FE_ALL_INVALID;
    103 	__mffs(&__r.__d);
    104 	__r.__bits.__reg &= ~__excepts;
    105 	__mtfsf(__r.__d);
    106 	return (0);
    107 }
    108 
    109 static __inline int
    110 fegetexceptflag(fexcept_t *__flagp, int __excepts)
    111 {
    112 	union __fpscr __r;
    113 
    114 	__mffs(&__r.__d);
    115 	*__flagp = __r.__bits.__reg & __excepts;
    116 	return (0);
    117 }
    118 
    119 static __inline int
    120 fesetexceptflag(const fexcept_t *__flagp, int __excepts)
    121 {
    122 	union __fpscr __r;
    123 
    124 	if (__excepts & FE_INVALID)
    125 		__excepts |= FE_ALL_EXCEPT;
    126 	__mffs(&__r.__d);
    127 	__r.__bits.__reg &= ~__excepts;
    128 	__r.__bits.__reg |= *__flagp & __excepts;
    129 	__mtfsf(__r.__d);
    130 	return (0);
    131 }
    132 
    133 static __inline int
    134 feraiseexcept(int __excepts)
    135 {
    136 	union __fpscr __r;
    137 
    138 	if (__excepts & FE_INVALID)
    139 		__excepts |= FE_VXSOFT;
    140 	__mffs(&__r.__d);
    141 	__r.__bits.__reg |= __excepts;
    142 	__mtfsf(__r.__d);
    143 	return (0);
    144 }
    145 
    146 static __inline int
    147 fetestexcept(int __excepts)
    148 {
    149 	union __fpscr __r;
    150 
    151 	__mffs(&__r.__d);
    152 	return (__r.__bits.__reg & __excepts);
    153 }
    154 
    155 static __inline int
    156 fegetround(void)
    157 {
    158 	union __fpscr __r;
    159 
    160 	__mffs(&__r.__d);
    161 	return (__r.__bits.__reg & _ROUND_MASK);
    162 }
    163 
    164 static __inline int
    165 fesetround(int __round)
    166 {
    167 	union __fpscr __r;
    168 
    169 	if (__round & ~_ROUND_MASK)
    170 		return (-1);
    171 	__mffs(&__r.__d);
    172 	__r.__bits.__reg &= ~_ROUND_MASK;
    173 	__r.__bits.__reg |= __round;
    174 	__mtfsf(__r.__d);
    175 	return (0);
    176 }
    177 
    178 static __inline int
    179 fegetenv(fenv_t *__envp)
    180 {
    181 	union __fpscr __r;
    182 
    183 	__mffs(&__r.__d);
    184 	*__envp = __r.__bits.__reg;
    185 	return (0);
    186 }
    187 
    188 static __inline int
    189 feholdexcept(fenv_t *__envp)
    190 {
    191 	union __fpscr __r;
    192 
    193 	__mffs(&__r.__d);
    194 	*__envp = __r.__d;
    195 	__r.__bits.__reg &= ~(FE_ALL_EXCEPT | _ENABLE_MASK);
    196 	__mtfsf(__r.__d);
    197 	return (0);
    198 }
    199 
    200 static __inline int
    201 fesetenv(const fenv_t *__envp)
    202 {
    203 	union __fpscr __r;
    204 
    205 	__r.__bits.__reg = *__envp;
    206 	__mtfsf(__r.__d);
    207 	return (0);
    208 }
    209 
    210 static __inline int
    211 feupdateenv(const fenv_t *__envp)
    212 {
    213 	union __fpscr __r;
    214 
    215 	__mffs(&__r.__d);
    216 	__r.__bits.__reg &= FE_ALL_EXCEPT;
    217 	__r.__bits.__reg |= *__envp;
    218 	__mtfsf(__r.__d);
    219 	return (0);
    220 }
    221 
    222 #if __BSD_VISIBLE
    223 
    224 static __inline int
    225 feenableexcept(int __mask)
    226 {
    227 	union __fpscr __r;
    228 	fenv_t __oldmask;
    229 
    230 	__mffs(&__r.__d);
    231 	__oldmask = __r.__bits.__reg;
    232 	__r.__bits.__reg |= (__mask & FE_ALL_EXCEPT) >> _FPUSW_SHIFT;
    233 	__mtfsf(__r.__d);
    234 	return ((__oldmask & _ENABLE_MASK) << _FPUSW_SHIFT);
    235 }
    236 
    237 static __inline int
    238 fedisableexcept(int __mask)
    239 {
    240 	union __fpscr __r;
    241 	fenv_t __oldmask;
    242 
    243 	__mffs(&__r.__d);
    244 	__oldmask = __r.__bits.__reg;
    245 	__r.__bits.__reg &= ~((__mask & FE_ALL_EXCEPT) >> _FPUSW_SHIFT);
    246 	__mtfsf(__r.__d);
    247 	return ((__oldmask & _ENABLE_MASK) << _FPUSW_SHIFT);
    248 }
    249 
    250 static __inline int
    251 fegetexcept(void)
    252 {
    253 	union __fpscr __r;
    254 
    255 	__mffs(&__r.__d);
    256 	return ((__r.__bits.__reg & _ENABLE_MASK) << _FPUSW_SHIFT);
    257 }
    258 
    259 #endif /* __BSD_VISIBLE */
    260 
    261 __END_DECLS
    262 
    263 #endif	/* !_FENV_H_ */
    264