ieeefp.h revision 226607
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: head/sys/amd64/include/ieeefp.h 226607 2011-10-21 06:41:46Z das $ 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,SSE}*FLD and {FP,SSE}*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 */ 55typedef 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 */ 65typedef 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 * SSE mxcsr register bit-field masks. 99 */ 100#define SSE_STKY_FLD 0x3f /* exception flags */ 101#define SSE_DAZ_FLD 0x40 /* Denormals are zero */ 102#define SSE_MSKS_FLD 0x1f80 /* exception masks field */ 103#define SSE_RND_FLD 0x6000 /* rounding control */ 104#define SSE_FZ_FLD 0x8000 /* flush to zero on underflow */ 105 106/* 107 * FPU control word bit-field offsets (shift counts). 108 */ 109#define FP_MSKS_OFF 0 /* exception masks offset */ 110#define FP_PRC_OFF 8 /* precision control offset */ 111#define FP_RND_OFF 10 /* rounding control offset */ 112 113/* 114 * FPU status word bit-field offsets (shift counts). 115 */ 116#define FP_STKY_OFF 0 /* sticky flags offset */ 117 118/* 119 * SSE mxcsr register bit-field offsets (shift counts). 120 */ 121#define SSE_STKY_OFF 0 /* exception flags offset */ 122#define SSE_DAZ_OFF 6 /* DAZ exception mask offset */ 123#define SSE_MSKS_OFF 7 /* other exception masks offset */ 124#define SSE_RND_OFF 13 /* rounding control offset */ 125#define SSE_FZ_OFF 15 /* flush to zero offset */ 126 127#ifdef __GNUCLIKE_ASM 128 129#define __fldcw(addr) __asm __volatile("fldcw %0" : : "m" (*(addr))) 130#define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr))) 131#define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr))) 132#define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr))) 133#define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr))) 134#define __ldmxcsr(addr) __asm __volatile("ldmxcsr %0" : : "m" (*(addr))) 135#define __stmxcsr(addr) __asm __volatile("stmxcsr %0" : "=m" (*(addr))) 136 137/* 138 * Load the control word. Be careful not to trap if there is a currently 139 * unmasked exception (ones that will become freshly unmasked are not a 140 * problem). This case must be handled by a save/restore of the 141 * environment or even of the full x87 state. Accessing the environment 142 * is very inefficient, so only do it when necessary. 143 */ 144static __inline void 145__fnldcw(unsigned short _cw, unsigned short _newcw) 146{ 147 struct { 148 unsigned _cw; 149 unsigned _other[6]; 150 } _env; 151 unsigned short _sw; 152 153 if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) { 154 __fnstsw(&_sw); 155 if (((_sw & ~_cw) & FP_STKY_FLD) != 0) { 156 __fnstenv(&_env); 157 _env._cw = _newcw; 158 __fldenv(&_env); 159 return; 160 } 161 } 162 __fldcw(&_newcw); 163} 164 165/* 166 * General notes about conflicting SSE vs FP status bits. 167 * This code assumes that software will not fiddle with the control 168 * bits of the SSE and x87 in such a way to get them out of sync and 169 * still expect this to work. Break this at your peril. 170 * Because I based this on the i386 port, the x87 state is used for 171 * the fpget*() functions, and is shadowed into the SSE state for 172 * the fpset*() functions. For dual source fpget*() functions, I 173 * merge the two together. I think. 174 */ 175 176static __inline fp_rnd_t 177__fpgetround(void) 178{ 179 unsigned short _cw; 180 181 __fnstcw(&_cw); 182 return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF)); 183} 184 185static __inline fp_rnd_t 186__fpsetround(fp_rnd_t _m) 187{ 188 fp_rnd_t _p; 189 unsigned _mxcsr; 190 unsigned short _cw, _newcw; 191 192 __fnstcw(&_cw); 193 _p = (fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF); 194 _newcw = _cw & ~FP_RND_FLD; 195 _newcw |= (_m << FP_RND_OFF) & FP_RND_FLD; 196 __fnldcw(_cw, _newcw); 197 __stmxcsr(&_mxcsr); 198 _mxcsr &= ~SSE_RND_FLD; 199 _mxcsr |= (_m << SSE_RND_OFF) & SSE_RND_FLD; 200 __ldmxcsr(&_mxcsr); 201 return (_p); 202} 203 204/* 205 * Get or set the rounding precision for x87 arithmetic operations. 206 * There is no equivalent SSE mode or control. 207 */ 208 209static __inline fp_prec_t 210__fpgetprec(void) 211{ 212 unsigned short _cw; 213 214 __fnstcw(&_cw); 215 return ((fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF)); 216} 217 218static __inline fp_prec_t 219__fpsetprec(fp_prec_t _m) 220{ 221 fp_prec_t _p; 222 unsigned short _cw, _newcw; 223 224 __fnstcw(&_cw); 225 _p = (fp_prec_t)((_cw & FP_PRC_FLD) >> FP_PRC_OFF); 226 _newcw = _cw & ~FP_PRC_FLD; 227 _newcw |= (_m << FP_PRC_OFF) & FP_PRC_FLD; 228 __fnldcw(_cw, _newcw); 229 return (_p); 230} 231 232/* 233 * Get or set the exception mask. 234 * Note that the x87 mask bits are inverted by the API -- a mask bit of 1 235 * means disable for x87 and SSE, but for fp*mask() it means enable. 236 */ 237 238static __inline fp_except_t 239__fpgetmask(void) 240{ 241 unsigned short _cw; 242 243 __fnstcw(&_cw); 244 return ((~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF); 245} 246 247static __inline fp_except_t 248__fpsetmask(fp_except_t _m) 249{ 250 fp_except_t _p; 251 unsigned _mxcsr; 252 unsigned short _cw, _newcw; 253 254 __fnstcw(&_cw); 255 _p = (~_cw & FP_MSKS_FLD) >> FP_MSKS_OFF; 256 _newcw = _cw & ~FP_MSKS_FLD; 257 _newcw |= (~_m << FP_MSKS_OFF) & FP_MSKS_FLD; 258 __fnldcw(_cw, _newcw); 259 __stmxcsr(&_mxcsr); 260 /* XXX should we clear non-ieee SSE_DAZ_FLD and SSE_FZ_FLD ? */ 261 _mxcsr &= ~SSE_MSKS_FLD; 262 _mxcsr |= (~_m << SSE_MSKS_OFF) & SSE_MSKS_FLD; 263 __ldmxcsr(&_mxcsr); 264 return (_p); 265} 266 267static __inline fp_except_t 268__fpgetsticky(void) 269{ 270 unsigned _ex, _mxcsr; 271 unsigned short _sw; 272 273 __fnstsw(&_sw); 274 _ex = (_sw & FP_STKY_FLD) >> FP_STKY_OFF; 275 __stmxcsr(&_mxcsr); 276 _ex |= (_mxcsr & SSE_STKY_FLD) >> SSE_STKY_OFF; 277 return ((fp_except_t)_ex); 278} 279 280#endif /* __GNUCLIKE_ASM */ 281 282#if !defined(__IEEEFP_NOINLINES__) && defined(__GNUCLIKE_ASM) 283 284#define fpgetmask() __fpgetmask() 285#define fpgetprec() __fpgetprec() 286#define fpgetround() __fpgetround() 287#define fpgetsticky() __fpgetsticky() 288#define fpsetmask(m) __fpsetmask(m) 289#define fpsetprec(m) __fpsetprec(m) 290#define fpsetround(m) __fpsetround(m) 291 292#else /* !(!__IEEEFP_NOINLINES__ && __GNUCLIKE_ASM) */ 293 294/* Augment the userland declarations. */ 295__BEGIN_DECLS 296extern fp_rnd_t fpgetround(void); 297extern fp_rnd_t fpsetround(fp_rnd_t); 298extern fp_except_t fpgetmask(void); 299extern fp_except_t fpsetmask(fp_except_t); 300extern fp_except_t fpgetsticky(void); 301extern fp_except_t fpsetsticky(fp_except_t); 302fp_prec_t fpgetprec(void); 303fp_prec_t fpsetprec(fp_prec_t); 304__END_DECLS 305 306#endif /* !__IEEEFP_NOINLINES__ && __GNUCLIKE_ASM */ 307 308#endif /* !_MACHINE_IEEEFP_H_ */ 309