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 uint32_t __mxcsr; 115 uint16_t __status; 116 117 __stmxcsr(&__mxcsr); 118 __fnstsw(&__status); 119 *__flagp = (__mxcsr | __status) & __excepts; 120 return (0); 121 } 122 123 int fesetexceptflag(const fexcept_t *__flagp, int __excepts); 124 int feraiseexcept(int __excepts); 125 126 static __inline int 127 fetestexcept(int __excepts) 128 { 129 uint32_t __mxcsr; 130 uint16_t __status; 131 132 __stmxcsr(&__mxcsr); 133 __fnstsw(&__status); 134 return ((__status | __mxcsr) & __excepts); 135 } 136 137 static __inline int 138 fegetround(void) 139 { 140 uint16_t __control; 141 142 /* 143 * We assume that the x87 and the SSE unit agree on the 144 * rounding mode. Reading the control word on the x87 turns 145 * out to be about 5 times faster than reading it on the SSE 146 * unit on an Opteron 244. 147 */ 148 __fnstcw(&__control); 149 return (__control & _ROUND_MASK); 150 } 151 152 static __inline int 153 fesetround(int __round) 154 { 155 uint32_t __mxcsr; 156 uint16_t __control; 157 158 if (__round & ~_ROUND_MASK) 159 return (-1); 160 161 __fnstcw(&__control); 162 __control &= ~_ROUND_MASK; 163 __control |= __round; 164 __fldcw(__control); 165 166 __stmxcsr(&__mxcsr); 167 __mxcsr &= ~(_ROUND_MASK << _SSE_ROUND_SHIFT); 168 __mxcsr |= __round << _SSE_ROUND_SHIFT; 169 __ldmxcsr(__mxcsr); 170 171 return (0); 172 } 173 174 int fegetenv(fenv_t *__envp); 175 int feholdexcept(fenv_t *__envp); 176 177 static __inline int 178 fesetenv(const fenv_t *__envp) 179 { 180 181 /* 182 * XXX Using fldenvx() instead of fldenv() tells the compiler that this 183 * instruction clobbers the i387 register stack. This happens because 184 * we restore the tag word from the saved environment. Normally, this 185 * would happen anyway and we wouldn't care, because the ABI allows 186 * function calls to clobber the i387 regs. However, fesetenv() is 187 * inlined, so we need to be more careful. 188 */ 189 __fldenvx(__envp->__x87); 190 __ldmxcsr(__envp->__mxcsr); 191 return (0); 192 } 193 194 int feupdateenv(const fenv_t *__envp); 195 196 #if __BSD_VISIBLE 197 198 int feenableexcept(int __mask); 199 int fedisableexcept(int __mask); 200 201 static __inline int 202 fegetexcept(void) 203 { 204 uint16_t __control; 205 206 /* 207 * We assume that the masks for the x87 and the SSE unit are 208 * the same. 209 */ 210 __fnstcw(&__control); 211 return (~__control & FE_ALL_EXCEPT); 212 } 213 214 #endif /* __BSD_VISIBLE */ 215 216 __END_DECLS 217 218 #endif /* !_FENV_H_ */ 219