1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 2003 Peter Wemm. 5 * Copyright (c) 1990 Andrew Moore, Talke Studio 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#) ieeefp.h 1.0 (Berkeley) 9/23/93 37 * $FreeBSD$ 38 */ 39 40 #ifndef _MACHINE_IEEEFP_H_ 41 #define _MACHINE_IEEEFP_H_ 42 43 /* 44 * Deprecated historical FPU control interface 45 * 46 * IEEE floating point type, constant and function definitions. 47 * XXX: {FP,SSE}*FLD and {FP,SSE}*OFF are undocumented pollution. 48 */ 49 50 #ifndef _SYS_CDEFS_H_ 51 #error this file needs sys/cdefs.h as a prerequisite 52 #endif 53 54 /* 55 * Rounding modes. 56 */ 57 typedef enum { 58 FP_RN=0, /* round to nearest */ 59 FP_RM, /* round down towards minus infinity */ 60 FP_RP, /* round up towards plus infinity */ 61 FP_RZ /* truncate */ 62 } fp_rnd_t; 63 64 /* 65 * Precision (i.e., rounding precision) modes. 66 */ 67 typedef enum { 68 FP_PS=0, /* 24 bit (single-precision) */ 69 FP_PRS, /* reserved */ 70 FP_PD, /* 53 bit (double-precision) */ 71 FP_PE /* 64 bit (extended-precision) */ 72 } fp_prec_t; 73 74 #define fp_except_t int 75 76 /* 77 * Exception bit masks. 78 */ 79 #define FP_X_INV 0x01 /* invalid operation */ 80 #define FP_X_DNML 0x02 /* denormal */ 81 #define FP_X_DZ 0x04 /* zero divide */ 82 #define FP_X_OFL 0x08 /* overflow */ 83 #define FP_X_UFL 0x10 /* underflow */ 84 #define FP_X_IMP 0x20 /* (im)precision */ 85 #define FP_X_STK 0x40 /* stack fault */ 86 87 /* 88 * FPU control word bit-field masks. 89 */ 90 #define FP_MSKS_FLD 0x3f /* exception masks field */ 91 #define FP_PRC_FLD 0x300 /* precision control field */ 92 #define FP_RND_FLD 0xc00 /* rounding control field */ 93 94 /* 95 * FPU status word bit-field masks. 96 */ 97 #define FP_STKY_FLD 0x3f /* sticky flags field */ 98 99 /* 100 * SSE mxcsr register bit-field masks. 101 */ 102 #define SSE_STKY_FLD 0x3f /* exception flags */ 103 #define SSE_DAZ_FLD 0x40 /* Denormals are zero */ 104 #define SSE_MSKS_FLD 0x1f80 /* exception masks field */ 105 #define SSE_RND_FLD 0x6000 /* rounding control */ 106 #define SSE_FZ_FLD 0x8000 /* flush to zero on underflow */ 107 108 /* 109 * FPU control word bit-field offsets (shift counts). 110 */ 111 #define FP_MSKS_OFF 0 /* exception masks offset */ 112 #define FP_PRC_OFF 8 /* precision control offset */ 113 #define FP_RND_OFF 10 /* rounding control offset */ 114 115 /* 116 * FPU status word bit-field offsets (shift counts). 117 */ 118 #define FP_STKY_OFF 0 /* sticky flags offset */ 119 120 /* 121 * SSE mxcsr register bit-field offsets (shift counts). 122 */ 123 #define SSE_STKY_OFF 0 /* exception flags offset */ 124 #define SSE_DAZ_OFF 6 /* DAZ exception mask offset */ 125 #define SSE_MSKS_OFF 7 /* other exception masks offset */ 126 #define SSE_RND_OFF 13 /* rounding control offset */ 127 #define SSE_FZ_OFF 15 /* flush to zero offset */ 128 129 #ifdef __GNUCLIKE_ASM 130 131 #define __fldcw(addr) __asm __volatile("fldcw %0" : : "m" (*(addr))) 132 #define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr))) 133 #define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr))) 134 #define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr))) 135 #define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr))) 136 #define __ldmxcsr(addr) __asm __volatile("ldmxcsr %0" : : "m" (*(addr))) 137 #define __stmxcsr(addr) __asm __volatile("stmxcsr %0" : "=m" (*(addr))) 138 139 /* 140 * Load the control word. Be careful not to trap if there is a currently 141 * unmasked exception (ones that will become freshly unmasked are not a 142 * problem). This case must be handled by a save/restore of the 143 * environment or even of the full x87 state. Accessing the environment 144 * is very inefficient, so only do it when necessary. 145 */ 146 static __inline void 147 __fnldcw(unsigned short _cw, unsigned short _newcw) 148 { 149 struct { 150 unsigned _cw; 151 unsigned _other[6]; 152 } _env; 153 unsigned short _sw; 154 155 if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) { 156 __fnstsw(&_sw); 157 if (((_sw & ~_cw) & FP_STKY_FLD) != 0) { 158 __fnstenv(&_env); 159 _env._cw = _newcw; 160 __fldenv(&_env); 161 return; 162 } 163 } 164 __fldcw(&_newcw); 165 } 166 167 /* 168 * General notes about conflicting SSE vs FP status bits. 169 * This code assumes that software will not fiddle with the control 170 * bits of the SSE and x87 in such a way to get them out of sync and 171 * still expect this to work. Break this at your peril. 172 * Because I based this on the i386 port, the x87 state is used for 173 * the fpget*() functions, and is shadowed into the SSE state for 174 * the fpset*() functions. For dual source fpget*() functions, I 175 * merge the two together. I think. 176 */ 177 178 static __inline fp_rnd_t 179 __fpgetround(void) 180 { 181 unsigned short _cw; 182 183 __fnstcw(&_cw); 184 return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF)); 185 } 186 187 static __inline fp_rnd_t 188 __fpsetround(fp_rnd_t _m) 189 { 190 fp_rnd_t _p; 191 unsigned _mxcsr; 192 unsigned short _cw, _newcw; 193 194 __fnstcw(&_cw); 195 _p = (fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF); 196 _newcw = _cw & ~FP_RND_FLD; 197 _newcw |= (_m << FP_RND_OFF) & FP_RND_FLD; 198 __fnldcw(_cw, _newcw); 199 __stmxcsr(&_mxcsr); 200 _mxcsr &= ~SSE_RND_FLD; 201 _mxcsr |= (_m << SSE_RND_OFF) & SSE_RND_FLD; 202 __ldmxcsr(&_mxcsr); 203 return (_p); 204 } 205 206 /* 207 * Get or set the rounding precision for x87 arithmetic operations. 208 * There is no equivalent SSE mode or control. 209 */ 210 211 static __inline fp_prec_t 212 __fpgetprec(void) 213 { 214 unsigned short _cw; 215 216 __fnstcw(&_cw); 217 return ((fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF)); 218 } 219 220 static __inline fp_prec_t 221 __fpsetprec(fp_prec_t _m) 222 { 223 fp_prec_t _p; 224 unsigned short _cw, _newcw; 225 226 __fnstcw(&_cw); 227 _p = (fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF); 228 _newcw = _cw & ~FP_PRC_FLD; 229 _newcw |= (_m << FP_PRC_OFF) & FP_PRC_FLD; 230 __fnldcw(_cw, _newcw); 231 return (_p); 232 } 233 234 /* 235 * Get or set the exception mask. 236 * Note that the x87 mask bits are inverted by the API -- a mask bit of 1 237 * means disable for x87 and SSE, but for fp*mask() it means enable. 238 */ 239 240 static __inline fp_except_t 241 __fpgetmask(void) 242 { 243 unsigned short _cw; 244 245 __fnstcw(&_cw); 246 return ((~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF); 247 } 248 249 static __inline fp_except_t 250 __fpsetmask(fp_except_t _m) 251 { 252 fp_except_t _p; 253 unsigned _mxcsr; 254 unsigned short _cw, _newcw; 255 256 __fnstcw(&_cw); 257 _p = (~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF; 258 _newcw = _cw & ~FP_MSKS_FLD; 259 _newcw |= (~_m << FP_MSKS_OFF) & FP_MSKS_FLD; 260 __fnldcw(_cw, _newcw); 261 __stmxcsr(&_mxcsr); 262 /* XXX should we clear non-ieee SSE_DAZ_FLD and SSE_FZ_FLD ? */ 263 _mxcsr &= ~SSE_MSKS_FLD; 264 _mxcsr |= (~_m << SSE_MSKS_OFF) & SSE_MSKS_FLD; 265 __ldmxcsr(&_mxcsr); 266 return (_p); 267 } 268 269 static __inline fp_except_t 270 __fpgetsticky(void) 271 { 272 unsigned _ex, _mxcsr; 273 unsigned short _sw; 274 275 __fnstsw(&_sw); 276 _ex = (_sw & FP_STKY_FLD) >> FP_STKY_OFF; 277 __stmxcsr(&_mxcsr); 278 _ex |= (_mxcsr & SSE_STKY_FLD) >> SSE_STKY_OFF; 279 return ((fp_except_t)_ex); 280 } 281 282 #endif /* __GNUCLIKE_ASM */ 283 284 #if !defined(__IEEEFP_NOINLINES__) && defined(__GNUCLIKE_ASM) 285 286 #define fpgetmask() __fpgetmask() 287 #define fpgetprec() __fpgetprec() 288 #define fpgetround() __fpgetround() 289 #define fpgetsticky() __fpgetsticky() 290 #define fpsetmask(m) __fpsetmask(m) 291 #define fpsetprec(m) __fpsetprec(m) 292 #define fpsetround(m) __fpsetround(m) 293 294 #else /* !(!__IEEEFP_NOINLINES__ && __GNUCLIKE_ASM) */ 295 296 /* Augment the userland declarations. */ 297 __BEGIN_DECLS 298 extern fp_rnd_t fpgetround(void); 299 extern fp_rnd_t fpsetround(fp_rnd_t); 300 extern fp_except_t fpgetmask(void); 301 extern fp_except_t fpsetmask(fp_except_t); 302 extern fp_except_t fpgetsticky(void); 303 extern fp_except_t fpsetsticky(fp_except_t); 304 fp_prec_t fpgetprec(void); 305 fp_prec_t fpsetprec(fp_prec_t); 306 __END_DECLS 307 308 #endif /* !__IEEEFP_NOINLINES__ && __GNUCLIKE_ASM */ 309 310 #endif /* !_MACHINE_IEEEFP_H_ */ 311