1 /* Copyright (C) 1997-2001,2004,2011 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, write to the Free 16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 17 02111-1307 USA. */ 18 19 #ifndef _FENV_H 20 # error "Never use <bits/fenv.h> directly; include <fenv.h> instead." 21 #endif 22 23 #include <bits/wordsize.h> 24 25 26 /* Define bits representing the exception. We use the bit positions 27 of the appropriate bits in the FPU control word. */ 28 enum 29 { 30 FE_INVALID = 0x01, 31 #define FE_INVALID FE_INVALID 32 __FE_DENORM = 0x02, 33 FE_DIVBYZERO = 0x04, 34 #define FE_DIVBYZERO FE_DIVBYZERO 35 FE_OVERFLOW = 0x08, 36 #define FE_OVERFLOW FE_OVERFLOW 37 FE_UNDERFLOW = 0x10, 38 #define FE_UNDERFLOW FE_UNDERFLOW 39 FE_INEXACT = 0x20 40 #define FE_INEXACT FE_INEXACT 41 }; 42 43 #define FE_ALL_EXCEPT \ 44 (FE_INEXACT | FE_DIVBYZERO | FE_UNDERFLOW | FE_OVERFLOW | FE_INVALID) 45 46 /* The ix87 FPU supports all of the four defined rounding modes. We 47 use again the bit positions in the FPU control word as the values 48 for the appropriate macros. */ 49 enum 50 { 51 FE_TONEAREST = 0, 52 #define FE_TONEAREST FE_TONEAREST 53 FE_DOWNWARD = 0x400, 54 #define FE_DOWNWARD FE_DOWNWARD 55 FE_UPWARD = 0x800, 56 #define FE_UPWARD FE_UPWARD 57 FE_TOWARDZERO = 0xc00 58 #define FE_TOWARDZERO FE_TOWARDZERO 59 }; 60 61 62 /* Type representing exception flags. */ 63 typedef unsigned short int fexcept_t; 64 65 66 /* Type representing floating-point environment. This structure 67 corresponds to the layout of the block written by the `fstenv' 68 instruction and has additional fields for the contents of the MXCSR 69 register as written by the `stmxcsr' instruction. */ 70 typedef struct 71 { 72 unsigned short int __control_word; 73 unsigned short int __unused1; 74 unsigned short int __status_word; 75 unsigned short int __unused2; 76 unsigned short int __tags; 77 unsigned short int __unused3; 78 unsigned int __eip; 79 unsigned short int __cs_selector; 80 unsigned int __opcode:11; 81 unsigned int __unused4:5; 82 unsigned int __data_offset; 83 unsigned short int __data_selector; 84 unsigned short int __unused5; 85 #if __WORDSIZE == 64 86 unsigned int __mxcsr; 87 #endif 88 } 89 fenv_t; 90 91 /* If the default argument is used we use this value. */ 92 #define FE_DFL_ENV ((__const fenv_t *) -1) 93 94 #ifdef __USE_GNU 95 /* Floating-point environment where none of the exception is masked. */ 96 # define FE_NOMASK_ENV ((__const fenv_t *) -2) 97 #endif 98 99 100 #ifdef __USE_EXTERN_INLINES 101 __BEGIN_DECLS 102 103 /* Optimized versions. */ 104 extern int __REDIRECT_NTH (__feraiseexcept_renamed, (int), feraiseexcept); 105 __extern_inline int 106 __NTH (feraiseexcept (int __excepts)) 107 { 108 if (__builtin_constant_p (__excepts) 109 && (__excepts & ~(FE_INVALID | FE_DIVBYZERO)) == 0) 110 { 111 if ((FE_INVALID & __excepts) != 0) 112 { 113 /* One example of a invalid operation is 0.0 / 0.0. */ 114 float __f = 0.0; 115 116 __asm__ __volatile__ ("divss %0, %0 " : : "x" (__f)); 117 (void) &__f; 118 } 119 if ((FE_DIVBYZERO & __excepts) != 0) 120 { 121 float __f = 1.0; 122 float __g = 0.0; 123 124 __asm__ __volatile__ ("divss %1, %0" : : "x" (__f), "x" (__g)); 125 (void) &__f; 126 } 127 128 return 0; 129 } 130 131 return __feraiseexcept_renamed (__excepts); 132 } 133 134 __END_DECLS 135 #endif 136
