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 <stdint.h> 33 #include <sys/cdefs.h> 34 #include <sys/types.h> 35 36 typedef struct { 37 struct { 38 uint32_t __control; 39 uint32_t __status; 40 uint32_t __tag; 41 char __other[16]; 42 } __x87; 43 uint32_t __mxcsr; 44 } fenv_t; 45 46 typedef uint16_t fexcept_t; 47 48 /* Exception flags */ 49 #define FE_INVALID 0x01 50 #define FE_DENORMAL 0x02 51 #define FE_DIVBYZERO 0x04 52 #define FE_OVERFLOW 0x08 53 #define FE_UNDERFLOW 0x10 54 #define FE_INEXACT 0x20 55 #define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \ 56 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW) 57 58 /* Rounding modes */ 59 #define FE_TONEAREST 0x0000 60 #define FE_DOWNWARD 0x0400 61 #define FE_UPWARD 0x0800 62 #define FE_TOWARDZERO 0x0c00 63 #define _ROUND_MASK (FE_TONEAREST | FE_DOWNWARD | \ 64 FE_UPWARD | FE_TOWARDZERO) 65 66 /* 67 * As compared to the x87 control word, the SSE unit's control word 68 * has the rounding control bits offset by 3 and the exception mask 69 * bits offset by 7. 70 */ 71 #define _SSE_ROUND_SHIFT 3 72 #define _SSE_EMASK_SHIFT 7 73 74 __BEGIN_DECLS 75 76 /* Default floating-point environment */ 77 extern const fenv_t __fe_dfl_env; 78 #define FE_DFL_ENV (&__fe_dfl_env) 79 80 #define __fldcw(__cw) __asm __volatile("fldcw %0" : : "m" (__cw)) 81 #define __fldenv(__env) __asm __volatile("fldenv %0" : : "m" (__env)) 82 #define __fldenvx(__env) __asm __volatile("fldenv %0" : : "m" (__env) \ 83 : "st", "st(1)", "st(2)", "st(3)", "st(4)", \ 84 "st(5)", "st(6)", "st(7)") 85 #define __fnclex() __asm __volatile("fnclex") 86 #define __fnstenv(__env) __asm __volatile("fnstenv %0" : "=m" (*(__env))) 87 #define __fnstcw(__cw) __asm __volatile("fnstcw %0" : "=m" (*(__cw))) 88 #define __fnstsw(__sw) __asm __volatile("fnstsw %0" : "=am" (*(__sw))) 89 #define __fwait() __asm __volatile("fwait") 90 #define __ldmxcsr(__csr) __asm __volatile("ldmxcsr %0" : : "m" (__csr)) 91 #define __stmxcsr(__csr) __asm __volatile("stmxcsr %0" : "=m" (*(__csr))) 92 93 static __inline int 94 feclearexcept(int __excepts) 95 { 96 fenv_t __env; 97 98 if (__excepts == FE_ALL_EXCEPT) { 99 __fnclex(); 100 } else { 101 __fnstenv(&__env.__x87); 102 __env.__x87.__status &= ~__excepts; 103 __fldenv(__env.__x87); 104 } 105 __stmxcsr(&__env.__mxcsr); 106 __env.__mxcsr &= ~__excepts; 107 __ldmxcsr(__env.__mxcsr); 108 return (0); 109 } 110 111 static __inline int 112 fegetexceptflag(fexcept_t *__flagp, int __excepts) 113 { 114 int __mxcsr, __status; 115 116 __stmxcsr(&__mxcsr); 117 __fnstsw(&__status); 118 *__flagp = (__mxcsr | __status) & __excepts; 119 return (0); 120 } 121 122 int fesetexceptflag(const fexcept_t *__flagp, int __excepts); 123 int feraiseexcept(int __excepts); 124 125 static __inline int 126 fetestexcept(int __excepts) 127 { 128 int __mxcsr, __status; 129 130 __stmxcsr(&__mxcsr); 131 __fnstsw(&__status); 132 return ((__status | __mxcsr) & __excepts); 133 } 134 135 static __inline int 136 fegetround(void) 137 { 138 int __control; 139 140 /* 141 * We assume that the x87 and the SSE unit agree on the 142 * rounding mode. Reading the control word on the x87 turns 143 * out to be about 5 times faster than reading it on the SSE 144 * unit on an Opteron 244. 145 */ 146 __fnstcw(&__control); 147 return (__control & _ROUND_MASK); 148 } 149 150 static __inline int 151 fesetround(int __round) 152 { 153 int __mxcsr, __control; 154 155 if (__round & ~_ROUND_MASK) 156 return (-1); 157 158 __fnstcw(&__control); 159 __control &= ~_ROUND_MASK; 160 __control |= __round; 161 __fldcw(__control); 162 163 __stmxcsr(&__mxcsr); 164 __mxcsr &= ~(_ROUND_MASK << _SSE_ROUND_SHIFT); 165 __mxcsr |= __round << _SSE_ROUND_SHIFT; 166 __ldmxcsr(__mxcsr); 167 168 return (0); 169 } 170 171 int fegetenv(fenv_t *__envp); 172 int feholdexcept(fenv_t *__envp); 173 174 static __inline int 175 fesetenv(const fenv_t *__envp) 176 { 177 178 /* 179 * XXX Using fldenvx() instead of fldenv() tells the compiler that this 180 * instruction clobbers the i387 register stack. This happens because 181 * we restore the tag word from the saved environment. Normally, this 182 * would happen anyway and we wouldn't care, because the ABI allows 183 * function calls to clobber the i387 regs. However, fesetenv() is 184 * inlined, so we need to be more careful. 185 */ 186 __fldenvx(__envp->__x87); 187 __ldmxcsr(__envp->__mxcsr); 188 return (0); 189 } 190 191 int feupdateenv(const fenv_t *__envp); 192 193 #if __BSD_VISIBLE 194 195 int feenableexcept(int __mask); 196 int fedisableexcept(int __mask); 197 198 static __inline int 199 fegetexcept(void) 200 { 201 int __control; 202 203 /* 204 * We assume that the masks for the x87 and the SSE unit are 205 * the same. 206 */ 207 __fnstcw(&__control); 208 return (~__control & FE_ALL_EXCEPT); 209 } 210 211 #endif /* __BSD_VISIBLE */ 212 213 __END_DECLS 214 215 #endif /* !_FENV_H_ */ 216