1 /* $NetBSD: fenv.h,v 1.1 2010/07/31 21:47:54 joerg Exp $ */ 2 /*- 3 * Copyright (c) 2004-2005 David Schultz <das (at) FreeBSD.ORG> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #ifndef _X86_FENV_H_ 29 #define _X86_FENV_H_ 30 31 #include <sys/stdint.h> 32 #include <i386/npx.h> 33 34 /* 35 * Each symbol representing a floating point exception expands to an integer 36 * constant expression with values, such that bitwise-inclusive ORs of _all 37 * combinations_ of the constants result in distinct values. 38 * 39 * We use such values that allow direct bitwise operations on FPU/SSE registers. 40 */ 41 #define FE_INVALID 0x01 /* 000000000001 */ 42 #define FE_DENORMAL 0x02 /* 000000000010 */ 43 #define FE_DIVBYZERO 0x04 /* 000000000100 */ 44 #define FE_OVERFLOW 0x08 /* 000000001000 */ 45 #define FE_UNDERFLOW 0x10 /* 000000010000 */ 46 #define FE_INEXACT 0x20 /* 000000100000 */ 47 48 /* 49 * The following symbol is simply the bitwise-inclusive OR of all floating-point 50 * exception constants defined above. 51 */ 52 #define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \ 53 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW) 54 55 /* 56 * Each symbol representing the rounding direction, expands to an integer 57 * constant expression whose value is distinct non-negative value. 58 * 59 * We use such values that allow direct bitwise operations on FPU/SSE registers. 60 */ 61 #define FE_TONEAREST 0x000 /* 000000000000 */ 62 #define FE_DOWNWARD 0x400 /* 010000000000 */ 63 #define FE_UPWARD 0x800 /* 100000000000 */ 64 #define FE_TOWARDZERO 0xC00 /* 110000000000 */ 65 66 /* 67 * As compared to the x87 control word, the SSE unit's control has the rounding 68 * control bits offset by 3 and the exception mask bits offset by 7 69 */ 70 #define __X87_ROUND_MASK 0xC00 /* 110000000000 */ 71 #define __SSE_ROUND_SHIFT 3 72 #define __SSE_EMASK_SHIFT 7 73 74 /* 75 * fenv_t represents the entire floating-point environment 76 */ 77 typedef struct { 78 struct { 79 uint16_t control; /* Control word register */ 80 uint16_t unused1; 81 uint16_t status; /* Status word register */ 82 uint16_t unused2; 83 uint16_t tag; /* Tag word register */ 84 uint16_t unused3; 85 uint32_t others[4]; /* EIP, Pointer Selector, etc */ 86 } x87; 87 88 uint32_t mxcsr; /* Control and status register */ 89 } fenv_t; 90 91 /* 92 * The following constant represents the default floating-point environment 93 * (that is, the one installed at program startup) and has type pointer to 94 * const-qualified fenv_t. 95 * 96 * It can be used as an argument to the functions within the <fenv.h> header 97 * that manage the floating-point environment. 98 */ 99 extern fenv_t __fe_dfl_env; 100 #define FE_DFL_ENV ((const fenv_t *) &__fe_dfl_env) 101 102 /* 103 * fexcept_t represents the floating-point status flags collectively, including 104 * any status the implementation associates with the flags. 105 * 106 * A floating-point status flag is a system variable whose value is set (but 107 * never cleared) when a floating-point exception is raised, which occurs as a 108 * side effect of exceptional floating-point arithmetic to provide auxiliary 109 * information. 110 * 111 * A floating-point control mode is a system variable whose value may be set by 112 * the user to affect the subsequent behavior of floating-point arithmetic. 113 */ 114 typedef uint32_t fexcept_t; 115 116 #endif /* ! _X86_FENV_H_ */ 117