1 /* 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2010-2019 Red Hat, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef _SYS_FENV_H 30 #define _SYS_FENV_H 1 31 32 #include <sys/cdefs.h> 33 34 #ifdef __cplusplus 35 extern "C" { 36 #endif 37 38 39 /* Primary sources: 40 41 The Open Group Base Specifications Issue 6: 42 http://www.opengroup.org/onlinepubs/000095399/basedefs/fenv.h.html 43 44 C99 Language spec (draft n1256): 45 <url unknown> 46 47 Intel(R) 64 and IA-32 Architectures Software Developer's Manuals: 48 http://www.intel.com/products/processor/manuals/ 49 50 GNU C library manual pages: 51 http://www.gnu.org/software/libc/manual/html_node/Control-Functions.html 52 http://www.gnu.org/software/libc/manual/html_node/Rounding.html 53 http://www.gnu.org/software/libc/manual/html_node/FP-Exceptions.html 54 http://www.gnu.org/software/libc/manual/html_node/Status-bit-operations.html 55 56 Linux online man page(s): 57 http://linux.die.net/man/3/fegetexcept 58 59 The documentation quotes these sources for reference. All definitions and 60 code have been developed solely based on the information from these specs. 61 62 */ 63 64 /* Represents the entire floating-point environment. The floating-point 65 environment refers collectively to any floating-point status flags and 66 control modes supported by the implementation. 67 In this implementation, the struct contains the state information from 68 the fstenv/fnstenv instructions and a copy of the SSE MXCSR, since GCC 69 uses SSE for a lot of floating-point operations. (Cygwin assumes i686 70 or above these days, as does the compiler.) */ 71 72 typedef struct _fenv_t 73 { 74 struct _fpu_env_info { 75 unsigned int _fpu_cw; /* low 16 bits only. */ 76 unsigned int _fpu_sw; /* low 16 bits only. */ 77 unsigned int _fpu_tagw; /* low 16 bits only. */ 78 unsigned int _fpu_ipoff; 79 unsigned int _fpu_ipsel; 80 unsigned int _fpu_opoff; 81 unsigned int _fpu_opsel; /* low 16 bits only. */ 82 } _fpu; 83 unsigned int _sse_mxcsr; 84 } fenv_t; 85 86 /* Represents the floating-point status flags collectively, including 87 any status the implementation associates with the flags. A floating-point 88 status flag is a system variable whose value is set (but never cleared) 89 when a floating-point exception is raised, which occurs as a side effect 90 of exceptional floating-point arithmetic to provide auxiliary information. 91 A floating-point control mode is a system variable whose value may be 92 set by the user to affect the subsequent behavior of floating-point 93 arithmetic. */ 94 95 typedef __uint32_t fexcept_t; 96 97 /* The <fenv.h> header shall define the following constants if and only 98 if the implementation supports the floating-point exception by means 99 of the floating-point functions feclearexcept(), fegetexceptflag(), 100 feraiseexcept(), fesetexceptflag(), and fetestexcept(). Each expands to 101 an integer constant expression with values such that bitwise-inclusive 102 ORs of all combinations of the constants result in distinct values. */ 103 104 #define FE_DIVBYZERO (1 << 2) 105 #define FE_INEXACT (1 << 5) 106 #define FE_INVALID (1 << 0) 107 #define FE_OVERFLOW (1 << 3) 108 #define FE_UNDERFLOW (1 << 4) 109 110 /* The <fenv.h> header shall define the following constant, which is 111 simply the bitwise-inclusive OR of all floating-point exception 112 constants defined above: */ 113 114 /* in agreement w/ Linux the subnormal exception will always be masked */ 115 #define FE_ALL_EXCEPT \ 116 (FE_INEXACT | FE_UNDERFLOW | FE_OVERFLOW | FE_DIVBYZERO | FE_INVALID) 117 118 /* The <fenv.h> header shall define the following constants if and only 119 if the implementation supports getting and setting the represented 120 rounding direction by means of the fegetround() and fesetround() 121 functions. Each expands to an integer constant expression whose values 122 are distinct non-negative vales. */ 123 124 #define FE_DOWNWARD (1) 125 #define FE_TONEAREST (0) 126 #define FE_TOWARDZERO (3) 127 #define FE_UPWARD (2) 128 129 /* Only Solaris and QNX implement fegetprec/fesetprec. As Solaris, use the 130 values defined by http://www.open-std.org/jtc1/sc22//WG14/www/docs/n752.htm 131 QNX defines different values. */ 132 #if __MISC_VISIBLE 133 #define FE_FLTPREC (0) 134 #define FE_DBLPREC (2) 135 #define FE_LDBLPREC (3) 136 #endif 137 /* Additional implementation-defined environments, with macro 138 definitions beginning with FE_ and an uppercase letter,and having 139 type "pointer to const-qualified fenv_t",may also be specified by 140 the implementation. */ 141 142 #if __GNU_VISIBLE 143 /* If possible, the GNU C Library defines a macro FE_NOMASK_ENV which 144 represents an environment where every exception raised causes a trap 145 to occur. You can test for this macro using #ifdef. It is only defined 146 if _GNU_SOURCE is defined. */ 147 extern const fenv_t *_fe_nomask_env; 148 #define FE_NOMASK_ENV (_fe_nomask_env) 149 #endif 150 151 #ifdef __CYGWIN__ 152 153 #if __MISC_VISIBLE 154 int fegetprec (void); 155 int fesetprec (int __prec); 156 #endif 157 158 #endif /* __CYGWIN__ */ 159 160 #ifdef __cplusplus 161 } 162 #endif 163 164 #endif /* _FENV_H */ 165
