1/*- 2 * Copyright (c) 2004-2005 David Schultz <das@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 * $FreeBSD$ 27 */ 28 29#ifndef _FENV_H_ 30#define _FENV_H_ 31 32#include <sys/cdefs.h> 33#include <sys/_types.h> 34 35/* 36 * To preserve binary compatibility with FreeBSD 5.3, we pack the 37 * mxcsr into some reserved fields, rather than changing sizeof(fenv_t). 38 */ 39typedef struct { 40 __uint16_t __control; 41 __uint16_t __mxcsr_hi; 42 __uint16_t __status; 43 __uint16_t __mxcsr_lo; 44 __uint32_t __tag; 45 char __other[16]; 46} fenv_t; 47 48#define __get_mxcsr(env) (((env).__mxcsr_hi << 16) | \ 49 ((env).__mxcsr_lo)) 50#define __set_mxcsr(env, x) do { \ 51 (env).__mxcsr_hi = (__uint32_t)(x) >> 16; \ 52 (env).__mxcsr_lo = (__uint16_t)(x); \ 53} while (0) 54 55typedef __uint16_t fexcept_t; 56 57/* Exception flags */ 58#define FE_INVALID 0x01 59#define FE_DENORMAL 0x02 60#define FE_DIVBYZERO 0x04 61#define FE_OVERFLOW 0x08 62#define FE_UNDERFLOW 0x10 63#define FE_INEXACT 0x20 64#define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \ 65 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW) 66 67/* Rounding modes */ 68#define FE_TONEAREST 0x0000 69#define FE_DOWNWARD 0x0400 70#define FE_UPWARD 0x0800 71#define FE_TOWARDZERO 0x0c00 72#define _ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \ 73 FE_UPWARD | FE_TOWARDZERO) 74 75/* 76 * As compared to the x87 control word, the SSE unit's control word 77 * has the rounding control bits offset by 3 and the exception mask 78 * bits offset by 7. 79 */ 80#define _SSE_ROUND_SHIFT 3 81#define _SSE_EMASK_SHIFT 7 82 83__BEGIN_DECLS 84 85/* After testing for SSE support once, we cache the result in __has_sse. */ 86enum __sse_support { __SSE_YES, __SSE_NO, __SSE_UNK }; 87extern enum __sse_support __has_sse; 88int __test_sse(void); 89#ifdef __SSE__ 90#define __HAS_SSE() 1 91#else 92#define __HAS_SSE() (__has_sse == __SSE_YES || \ 93 (__has_sse == __SSE_UNK && __test_sse())) 94#endif 95 96/* Default floating-point environment */ 97extern const fenv_t __fe_dfl_env; 98#define FE_DFL_ENV (&__fe_dfl_env) 99 100#define __fldcw(__cw) __asm __volatile("fldcw %0" : : "m" (__cw)) 101#define __fldenv(__env) __asm __volatile("fldenv %0" : : "m" (__env)) 102#define __fldenvx(__env) __asm __volatile("fldenv %0" : : "m" (__env) \ 103 : "st", "st(1)", "st(2)", "st(3)", "st(4)", \ 104 "st(5)", "st(6)", "st(7)") 105#define __fnclex() __asm __volatile("fnclex") 106#define __fnstenv(__env) __asm __volatile("fnstenv %0" : "=m" (*(__env))) 107#define __fnstcw(__cw) __asm __volatile("fnstcw %0" : "=m" (*(__cw))) 108#define __fnstsw(__sw) __asm __volatile("fnstsw %0" : "=am" (*(__sw))) 109#define __fwait() __asm __volatile("fwait") 110#define __ldmxcsr(__csr) __asm __volatile("ldmxcsr %0" : : "m" (__csr)) 111#define __stmxcsr(__csr) __asm __volatile("stmxcsr %0" : "=m" (*(__csr))) 112 113static __inline int 114feclearexcept(int __excepts) 115{ 116 fenv_t __env; 117 int __mxcsr; 118 119 if (__excepts == FE_ALL_EXCEPT) { 120 __fnclex(); 121 } else { 122 __fnstenv(&__env); 123 __env.__status &= ~__excepts; 124 __fldenv(__env); 125 } 126 if (__HAS_SSE()) { 127 __stmxcsr(&__mxcsr); 128 __mxcsr &= ~__excepts; 129 __ldmxcsr(__mxcsr); 130 } 131 return (0); 132} 133 134static __inline int 135fegetexceptflag(fexcept_t *__flagp, int __excepts) 136{ 137 int __mxcsr; 138 __uint16_t __status; 139 140 __fnstsw(&__status); 141 if (__HAS_SSE()) 142 __stmxcsr(&__mxcsr); 143 else 144 __mxcsr = 0; 145 *__flagp = (__mxcsr | __status) & __excepts; 146 return (0); 147} 148 149int fesetexceptflag(const fexcept_t *__flagp, int __excepts); 150int feraiseexcept(int __excepts); 151 152static __inline int 153fetestexcept(int __excepts) 154{ 155 int __mxcsr; 156 __uint16_t __status; 157 158 __fnstsw(&__status); 159 if (__HAS_SSE()) 160 __stmxcsr(&__mxcsr); 161 else 162 __mxcsr = 0; 163 return ((__status | __mxcsr) & __excepts); 164} 165 166static __inline int 167fegetround(void) 168{ 169 int __control; 170 171 /* 172 * We assume that the x87 and the SSE unit agree on the 173 * rounding mode. Reading the control word on the x87 turns 174 * out to be about 5 times faster than reading it on the SSE 175 * unit on an Opteron 244. 176 */ 177 __fnstcw(&__control); 178 return (__control & _ROUND_MASK); 179} 180 181static __inline int 182fesetround(int __round) 183{ 184 int __mxcsr, __control; 185 186 if (__round & ~_ROUND_MASK) 187 return (-1); 188 189 __fnstcw(&__control); 190 __control &= ~_ROUND_MASK; 191 __control |= __round; 192 __fldcw(__control); 193 194 if (__HAS_SSE()) { 195 __stmxcsr(&__mxcsr); 196 __mxcsr &= ~(_ROUND_MASK << _SSE_ROUND_SHIFT); 197 __mxcsr |= __round << _SSE_ROUND_SHIFT; 198 __ldmxcsr(__mxcsr); 199 } 200 201 return (0); 202} 203 204int fegetenv(fenv_t *__envp); 205int feholdexcept(fenv_t *__envp); 206 207static __inline int 208fesetenv(const fenv_t *__envp) 209{ 210 fenv_t __env = *__envp; 211 int __mxcsr; 212 213 __mxcsr = __get_mxcsr(__env); 214 __set_mxcsr(__env, 0xffffffff); 215 /* 216 * XXX Using fldenvx() instead of fldenv() tells the compiler that this 217 * instruction clobbers the i387 register stack. This happens because 218 * we restore the tag word from the saved environment. Normally, this 219 * would happen anyway and we wouldn't care, because the ABI allows 220 * function calls to clobber the i387 regs. However, fesetenv() is 221 * inlined, so we need to be more careful. 222 */ 223 __fldenvx(__env); 224 if (__HAS_SSE()) 225 __ldmxcsr(__mxcsr); 226 return (0); 227} 228 229int feupdateenv(const fenv_t *__envp); 230 231#if __BSD_VISIBLE 232 233int feenableexcept(int __mask); 234int fedisableexcept(int __mask); 235 236static __inline int 237fegetexcept(void) 238{ 239 int __control; 240 241 /* 242 * We assume that the masks for the x87 and the SSE unit are 243 * the same. 244 */ 245 __fnstcw(&__control); 246 return (~__control & FE_ALL_EXCEPT); 247} 248 249#endif /* __BSD_VISIBLE */ 250 251__END_DECLS 252 253#endif /* !_FENV_H_ */ 254