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 typedef struct { 36 struct { 37 __uint32_t __control; 38 __uint32_t __status; 39 __uint32_t __tag; 40 char __other[16]; 41 } __x87; 42 __uint32_t __mxcsr; 43 } fenv_t; 44 45 typedef __uint16_t fexcept_t; 46 47 /* Exception flags */ 48 #define FE_INVALID 0x01 49 #define FE_DENORMAL 0x02 50 #define FE_DIVBYZERO 0x04 51 #define FE_OVERFLOW 0x08 52 #define FE_UNDERFLOW 0x10 53 #define FE_INEXACT 0x20 54 #define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \ 55 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW) 56 57 /* Rounding modes */ 58 #define FE_TONEAREST 0x0000 59 #define FE_DOWNWARD 0x0400 60 #define FE_UPWARD 0x0800 61 #define FE_TOWARDZERO 0x0c00 62 #define _ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \ 63 FE_UPWARD | FE_TOWARDZERO) 64 65 /* 66 * As compared to the x87 control word, the SSE unit's control word 67 * has the rounding control bits offset by 3 and the exception mask 68 * bits offset by 7. 69 */ 70 #define _SSE_ROUND_SHIFT 3 71 #define _SSE_EMASK_SHIFT 7 72 73 __BEGIN_DECLS 74 75 /* Default floating-point environment */ 76 extern const fenv_t __fe_dfl_env; 77 #define FE_DFL_ENV (&__fe_dfl_env) 78 79 #define __fldcw(__cw) __asm __volatile("fldcw %0" : : "m" (__cw)) 80 #define __fldenv(__env) __asm __volatile("fldenv %0" : : "m" (__env)) 81 #define __fldenvx(__env) __asm __volatile("fldenv %0" : : "m" (__env) \ 82 : "st", "st(1)", "st(2)", "st(3)", "st(4)", \ 83 "st(5)", "st(6)", "st(7)") 84 #define __fnclex() __asm __volatile("fnclex") 85 #define __fnstenv(__env) __asm __volatile("fnstenv %0" : "=m" (*(__env))) 86 #define __fnstcw(__cw) __asm __volatile("fnstcw %0" : "=m" (*(__cw))) 87 #define __fnstsw(__sw) __asm __volatile("fnstsw %0" : "=am" (*(__sw))) 88 #define __fwait() __asm __volatile("fwait") 89 #define __ldmxcsr(__csr) __asm __volatile("ldmxcsr %0" : : "m" (__csr)) 90 #define __stmxcsr(__csr) __asm __volatile("stmxcsr %0" : "=m" (*(__csr))) 91 92 static __inline int 93 feclearexcept(int __excepts) 94 { 95 fenv_t __env; 96 97 if (__excepts == FE_ALL_EXCEPT) { 98 __fnclex(); 99 } else { 100 __fnstenv(&__env.__x87); 101 __env.__x87.__status &= ~__excepts; 102 __fldenv(__env.__x87); 103 } 104 __stmxcsr(&__env.__mxcsr); 105 __env.__mxcsr &= ~__excepts; 106 __ldmxcsr(__env.__mxcsr); 107 return (0); 108 } 109 110 static __inline int 111 fegetexceptflag(fexcept_t *__flagp, int __excepts) 112 { 113 int __mxcsr, __status; 114 115 __stmxcsr(&__mxcsr); 116 __fnstsw(&__status); 117 *__flagp = (__mxcsr | __status) & __excepts; 118 return (0); 119 } 120 121 int fesetexceptflag(const fexcept_t *__flagp, int __excepts); 122 int feraiseexcept(int __excepts); 123 124 static __inline int 125 fetestexcept(int __excepts) 126 { 127 int __mxcsr, __status; 128 129 __stmxcsr(&__mxcsr); 130 __fnstsw(&__status); 131 return ((__status | __mxcsr) & __excepts); 132 } 133 134 static __inline int 135 fegetround(void) 136 { 137 int __control; 138 139 /* 140 * We assume that the x87 and the SSE unit agree on the 141 * rounding mode. Reading the control word on the x87 turns 142 * out to be about 5 times faster than reading it on the SSE 143 * unit on an Opteron 244. 144 */ 145 __fnstcw(&__control); 146 return (__control & _ROUND_MASK); 147 } 148 149 static __inline int 150 fesetround(int __round) 151 { 152 int __mxcsr, __control; 153 154 if (__round & ~_ROUND_MASK) 155 return (-1); 156 157 __fnstcw(&__control); 158 __control &= ~_ROUND_MASK; 159 __control |= __round; 160 __fldcw(__control); 161 162 __stmxcsr(&__mxcsr); 163 __mxcsr &= ~(_ROUND_MASK << _SSE_ROUND_SHIFT); 164 __mxcsr |= __round << _SSE_ROUND_SHIFT; 165 __ldmxcsr(__mxcsr); 166 167 return (0); 168 } 169 170 int fegetenv(fenv_t *__envp); 171 int feholdexcept(fenv_t *__envp); 172 173 static __inline int 174 fesetenv(const fenv_t *__envp) 175 { 176 177 /* 178 * XXX Using fldenvx() instead of fldenv() tells the compiler that this 179 * instruction clobbers the i387 register stack. This happens because 180 * we restore the tag word from the saved environment. Normally, this 181 * would happen anyway and we wouldn't care, because the ABI allows 182 * function calls to clobber the i387 regs. However, fesetenv() is 183 * inlined, so we need to be more careful. 184 */ 185 __fldenvx(__envp->__x87); 186 __ldmxcsr(__envp->__mxcsr); 187 return (0); 188 } 189 190 int feupdateenv(const fenv_t *__envp); 191 192 #if __BSD_VISIBLE 193 194 int feenableexcept(int __mask); 195 int fedisableexcept(int __mask); 196 197 static __inline int 198 fegetexcept(void) 199 { 200 int __control; 201 202 /* 203 * We assume that the masks for the x87 and the SSE unit are 204 * the same. 205 */ 206 __fnstcw(&__control); 207 return (~__control & FE_ALL_EXCEPT); 208 } 209 210 #endif /* __BSD_VISIBLE */ 211 212 __END_DECLS 213 214 #endif /* !_FENV_H_ */ 215