1 /*- 2 * Copyright (c) 2003 Peter Wemm. 3 * Copyright (c) 1990 Andrew Moore, Talke Studio 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by the University of 17 * California, Berkeley and its contributors. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#) ieeefp.h 1.0 (Berkeley) 9/23/93 35 * $FreeBSD$ 36 */ 37 38 #ifndef _MACHINE_IEEEFP_H_ 39 #define _MACHINE_IEEEFP_H_ 40 41 /* 42 * Deprecated historical FPU control interface 43 * 44 * IEEE floating point type, constant and function definitions. 45 * XXX: FP*FLD and FP*OFF are undocumented pollution. 46 */ 47 48 #ifndef _SYS_CDEFS_H_ 49 #error this file needs sys/cdefs.h as a prerequisite 50 #endif 51 52 /* 53 * Rounding modes. 54 */ 55 typedef enum { 56 FP_RN=0, /* round to nearest */ 57 FP_RM, /* round down towards minus infinity */ 58 FP_RP, /* round up towards plus infinity */ 59 FP_RZ /* truncate */ 60 } fp_rnd_t; 61 62 /* 63 * Precision (i.e., rounding precision) modes. 64 */ 65 typedef enum { 66 FP_PS=0, /* 24 bit (single-precision) */ 67 FP_PRS, /* reserved */ 68 FP_PD, /* 53 bit (double-precision) */ 69 FP_PE /* 64 bit (extended-precision) */ 70 } fp_prec_t; 71 72 #define fp_except_t int 73 74 /* 75 * Exception bit masks. 76 */ 77 #define FP_X_INV 0x01 /* invalid operation */ 78 #define FP_X_DNML 0x02 /* denormal */ 79 #define FP_X_DZ 0x04 /* zero divide */ 80 #define FP_X_OFL 0x08 /* overflow */ 81 #define FP_X_UFL 0x10 /* underflow */ 82 #define FP_X_IMP 0x20 /* (im)precision */ 83 #define FP_X_STK 0x40 /* stack fault */ 84 85 /* 86 * FPU control word bit-field masks. 87 */ 88 #define FP_MSKS_FLD 0x3f /* exception masks field */ 89 #define FP_PRC_FLD 0x300 /* precision control field */ 90 #define FP_RND_FLD 0xc00 /* rounding control field */ 91 92 /* 93 * FPU status word bit-field masks. 94 */ 95 #define FP_STKY_FLD 0x3f /* sticky flags field */ 96 97 /* 98 * FPU control word bit-field offsets (shift counts). 99 */ 100 #define FP_MSKS_OFF 0 /* exception masks offset */ 101 #define FP_PRC_OFF 8 /* precision control offset */ 102 #define FP_RND_OFF 10 /* rounding control offset */ 103 104 /* 105 * FPU status word bit-field offsets (shift counts). 106 */ 107 #define FP_STKY_OFF 0 /* sticky flags offset */ 108 109 #ifdef __GNUCLIKE_ASM 110 111 #define __fldcw(addr) __asm __volatile("fldcw %0" : : "m" (*(addr))) 112 #define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr))) 113 #define __fnclex() __asm __volatile("fnclex") 114 #define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr))) 115 #define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr))) 116 #define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr))) 117 118 /* 119 * Load the control word. Be careful not to trap if there is a currently 120 * unmasked exception (ones that will become freshly unmasked are not a 121 * problem). This case must be handled by a save/restore of the 122 * environment or even of the full x87 state. Accessing the environment 123 * is very inefficient, so only do it when necessary. 124 */ 125 static __inline void 126 __fnldcw(unsigned short _cw, unsigned short _newcw) 127 { 128 struct { 129 unsigned _cw; 130 unsigned _other[6]; 131 } _env; 132 unsigned short _sw; 133 134 if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) { 135 __fnstsw(&_sw); 136 if (((_sw & ~_cw) & FP_STKY_FLD) != 0) { 137 __fnstenv(&_env); 138 _env._cw = _newcw; 139 __fldenv(&_env); 140 return; 141 } 142 } 143 __fldcw(&_newcw); 144 } 145 146 static __inline fp_rnd_t 147 fpgetround(void) 148 { 149 unsigned short _cw; 150 151 __fnstcw(&_cw); 152 return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF)); 153 } 154 155 static __inline fp_rnd_t 156 fpsetround(fp_rnd_t _m) 157 { 158 fp_rnd_t _p; 159 unsigned short _cw, _newcw; 160 161 __fnstcw(&_cw); 162 _p = (fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF); 163 _newcw = _cw & ~FP_RND_FLD; 164 _newcw |= (_m << FP_RND_OFF) & FP_RND_FLD; 165 __fnldcw(_cw, _newcw); 166 return (_p); 167 } 168 169 static __inline fp_prec_t 170 fpgetprec(void) 171 { 172 unsigned short _cw; 173 174 __fnstcw(&_cw); 175 return ((fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF)); 176 } 177 178 static __inline fp_prec_t 179 fpsetprec(fp_prec_t _m) 180 { 181 fp_prec_t _p; 182 unsigned short _cw, _newcw; 183 184 __fnstcw(&_cw); 185 _p = (fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF); 186 _newcw = _cw & ~FP_PRC_FLD; 187 _newcw |= (_m << FP_PRC_OFF) & FP_PRC_FLD; 188 __fnldcw(_cw, _newcw); 189 return (_p); 190 } 191 192 /* 193 * Get or set the exception mask. 194 * Note that the x87 mask bits are inverted by the API -- a mask bit of 1 195 * means disable for x87 and SSE, but for fp*mask() it means enable. 196 */ 197 198 static __inline fp_except_t 199 fpgetmask(void) 200 { 201 unsigned short _cw; 202 203 __fnstcw(&_cw); 204 return ((~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF); 205 } 206 207 static __inline fp_except_t 208 fpsetmask(fp_except_t _m) 209 { 210 fp_except_t _p; 211 unsigned short _cw, _newcw; 212 213 __fnstcw(&_cw); 214 _p = (~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF; 215 _newcw = _cw & ~FP_MSKS_FLD; 216 _newcw |= (~_m << FP_MSKS_OFF) & FP_MSKS_FLD; 217 __fnldcw(_cw, _newcw); 218 return (_p); 219 } 220 221 static __inline fp_except_t 222 fpgetsticky(void) 223 { 224 unsigned _ex; 225 unsigned short _sw; 226 227 __fnstsw(&_sw); 228 _ex = (_sw & FP_STKY_FLD) >> FP_STKY_OFF; 229 return ((fp_except_t)_ex); 230 } 231 232 static __inline fp_except_t 233 fpresetsticky(fp_except_t _m) 234 { 235 struct { 236 unsigned _cw; 237 unsigned _sw; 238 unsigned _other[5]; 239 } _env; 240 fp_except_t _p; 241 242 _m &= FP_STKY_FLD >> FP_STKY_OFF; 243 _p = fpgetsticky(); 244 if ((_p & ~_m) == _p) 245 return (_p); 246 if ((_p & ~_m) == 0) { 247 __fnclex(); 248 return (_p); 249 } 250 __fnstenv(&_env); 251 _env._sw &= ~_m; 252 __fldenv(&_env); 253 return (_p); 254 } 255 256 #endif /* __GNUCLIKE_ASM */ 257 258 #endif /* !_MACHINE_IEEEFP_H_ */ 259