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: src/lib/msun/amd64/fenv.h,v 1.8 2011/10/10 15:43:09 das Exp $ 27 */ 28 29 #ifndef _FENV_H_ 30 #define _FENV_H_ 31 32 #include "cdefs-compat.h" 33 #include "types-compat.h" 34 35 #include "math_private.h" 36 37 #ifndef __fenv_static 38 #define __fenv_static static 39 #endif 40 41 typedef struct { 42 struct { 43 uint32_t __control; 44 uint32_t __status; 45 uint32_t __tag; 46 char __other[16]; 47 } __x87; 48 uint32_t __mxcsr; 49 } fenv_t; 50 51 typedef uint16_t fexcept_t; 52 53 /* Exception flags */ 54 #define FE_INVALID 0x01 55 #define FE_DENORMAL 0x02 56 #define FE_DIVBYZERO 0x04 57 #define FE_OVERFLOW 0x08 58 #define FE_UNDERFLOW 0x10 59 #define FE_INEXACT 0x20 60 #define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \ 61 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW) 62 63 /* Rounding modes */ 64 #define FE_TONEAREST 0x0000 65 #define FE_DOWNWARD 0x0400 66 #define FE_UPWARD 0x0800 67 #define FE_TOWARDZERO 0x0c00 68 #define _ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \ 69 FE_UPWARD | FE_TOWARDZERO) 70 71 /* 72 * As compared to the x87 control word, the SSE unit's control word 73 * has the rounding control bits offset by 3 and the exception mask 74 * bits offset by 7. 75 */ 76 #define _SSE_ROUND_SHIFT 3 77 #define _SSE_EMASK_SHIFT 7 78 79 __BEGIN_DECLS 80 81 /* Default floating-point environment */ 82 extern const fenv_t __fe_dfl_env; 83 #define FE_DFL_ENV (&__fe_dfl_env) 84 85 #define __fldcw(__cw) __asm __volatile("fldcw %0" : : "m" (__cw)) 86 #define __fldenv(__env) __asm __volatile("fldenv %0" : : "m" (__env)) 87 #define __fldenvx(__env) __asm __volatile("fldenv %0" : : "m" (__env) \ 88 : "st", "st(1)", "st(2)", "st(3)", "st(4)", \ 89 "st(5)", "st(6)", "st(7)") 90 #define __fnclex() __asm __volatile("fnclex") 91 #define __fnstenv(__env) __asm __volatile("fnstenv %0" : "=m" (*(__env))) 92 #define __fnstcw(__cw) __asm __volatile("fnstcw %0" : "=m" (*(__cw))) 93 #define __fnstsw(__sw) __asm __volatile("fnstsw %0" : "=am" (*(__sw))) 94 #define __fwait() __asm __volatile("fwait") 95 #define __ldmxcsr(__csr) __asm __volatile("ldmxcsr %0" : : "m" (__csr)) 96 #define __stmxcsr(__csr) __asm __volatile("stmxcsr %0" : "=m" (*(__csr))) 97 98 __fenv_static __attribute__((always_inline)) DLLEXPORT inline int 99 feclearexcept(int __excepts) 100 { 101 fenv_t __env; 102 103 if (__excepts == FE_ALL_EXCEPT) { 104 __fnclex(); 105 } else { 106 __fnstenv(&__env.__x87); 107 __env.__x87.__status &= ~__excepts; 108 __fldenv(__env.__x87); 109 } 110 __stmxcsr(&__env.__mxcsr); 111 __env.__mxcsr &= ~__excepts; 112 __ldmxcsr(__env.__mxcsr); 113 return (0); 114 } 115 116 __fenv_static DLLEXPORT inline int 117 fegetexceptflag(fexcept_t *__flagp, int __excepts) 118 { 119 uint32_t __mxcsr; 120 uint16_t __status; 121 122 __stmxcsr(&__mxcsr); 123 __fnstsw(&__status); 124 *__flagp = (__mxcsr | __status) & __excepts; 125 return (0); 126 } 127 128 DLLEXPORT int fesetexceptflag(const fexcept_t *__flagp, int __excepts); 129 DLLEXPORT int feraiseexcept(int __excepts); 130 131 __fenv_static __attribute__((always_inline)) DLLEXPORT inline int 132 fetestexcept(int __excepts) 133 { 134 uint32_t __mxcsr; 135 uint16_t __status; 136 137 __stmxcsr(&__mxcsr); 138 __fnstsw(&__status); 139 return ((__status | __mxcsr) & __excepts); 140 } 141 142 __fenv_static DLLEXPORT inline int 143 fegetround(void) 144 { 145 uint16_t __control; 146 147 /* 148 * We assume that the x87 and the SSE unit agree on the 149 * rounding mode. Reading the control word on the x87 turns 150 * out to be about 5 times faster than reading it on the SSE 151 * unit on an Opteron 244. 152 */ 153 __fnstcw(&__control); 154 return (__control & _ROUND_MASK); 155 } 156 157 __fenv_static DLLEXPORT inline int 158 fesetround(int __round) 159 { 160 uint32_t __mxcsr; 161 uint16_t __control; 162 163 if (__round & ~_ROUND_MASK) 164 return (-1); 165 166 __fnstcw(&__control); 167 __control &= ~_ROUND_MASK; 168 __control |= __round; 169 __fldcw(__control); 170 171 __stmxcsr(&__mxcsr); 172 __mxcsr &= ~(_ROUND_MASK << _SSE_ROUND_SHIFT); 173 __mxcsr |= __round << _SSE_ROUND_SHIFT; 174 __ldmxcsr(__mxcsr); 175 176 return (0); 177 } 178 179 DLLEXPORT int fegetenv(fenv_t *__envp); 180 DLLEXPORT int feholdexcept(fenv_t *__envp); 181 182 __fenv_static DLLEXPORT inline int 183 fesetenv(const fenv_t *__envp) 184 { 185 186 /* 187 * XXX Using fldenvx() instead of fldenv() tells the compiler that this 188 * instruction clobbers the i387 register stack. This happens because 189 * we restore the tag word from the saved environment. Normally, this 190 * would happen anyway and we wouldn't care, because the ABI allows 191 * function calls to clobber the i387 regs. However, fesetenv() is 192 * inlined, so we need to be more careful. 193 */ 194 __fldenvx(__envp->__x87); 195 __ldmxcsr(__envp->__mxcsr); 196 return (0); 197 } 198 199 DLLEXPORT int feupdateenv(const fenv_t *__envp); 200 201 #if __BSD_VISIBLE 202 203 DLLEXPORT int feenableexcept(int __mask); 204 DLLEXPORT int fedisableexcept(int __mask); 205 206 /* We currently provide no external definition of fegetexcept(). */ 207 static inline DLLEXPORT int 208 fegetexcept(void) 209 { 210 uint16_t __control; 211 212 /* 213 * We assume that the masks for the x87 and the SSE unit are 214 * the same. 215 */ 216 __fnstcw(&__control); 217 return (~__control & FE_ALL_EXCEPT); 218 } 219 220 #endif /* __BSD_VISIBLE */ 221 222 __END_DECLS 223 224 #endif /* !_FENV_H_ */ 225