ieee.h revision 1.4
1 /* $NetBSD: ieee.h,v 1.4 2003/10/25 18:19:10 kleink Exp $ */ 2 3 /* 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This software was developed by the Computer Systems Engineering group 8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 9 * contributed to Berkeley. 10 * 11 * All advertising materials mentioning features or use of this software 12 * must display the following acknowledgement: 13 * This product includes software developed by the University of 14 * California, Lawrence Berkeley Laboratory. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 3. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)ieee.h 8.1 (Berkeley) 6/11/93 41 */ 42 43 /* 44 * ieee.h defines the machine-dependent layout of the machine's IEEE 45 * floating point. 46 */ 47 48 /* 49 * Define the number of bits in each fraction and exponent. 50 * 51 * k k+1 52 * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented 53 * 54 * (-exp_bias+1) 55 * as fractions that look like 0.fffff x 2 . This means that 56 * 57 * -126 58 * the number 0.10000 x 2 , for instance, is the same as the normalized 59 * 60 * -127 -128 61 * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero 62 * 63 * -129 64 * in the fraction; to represent 2 , we need two, and so on. This 65 * 66 * (-exp_bias-fracbits+1) 67 * implies that the smallest denormalized number is 2 68 * 69 * for whichever format we are talking about: for single precision, for 70 * 71 * -126 -149 72 * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and 73 * 74 * -149 == -127 - 23 + 1. 75 */ 76 77 /* 78 * The ARM has two sets of FP data formats. The FPA supports 32-bit, 64-bit 79 * and 96-bit IEEE formats, with the words in big-endian order. VFP supports 80 * 32-bin and 64-bit IEEE formats with the words in the CPU's native byte 81 * order. 82 * 83 * The FPA also has two packed decimal formats, but we ignore them here. 84 */ 85 86 #define SNG_EXPBITS 8 87 #define SNG_FRACBITS 23 88 89 #define DBL_EXPBITS 11 90 #define DBL_FRACBITS 52 91 92 #ifndef __VFP_FP__ 93 #define EXT_EXPBITS 15 94 #define EXT_FRACBITS 64 95 #endif 96 97 struct ieee_single { 98 u_int sng_frac:23; 99 u_int sng_exponent:8; 100 u_int sng_sign:1; 101 }; 102 103 #ifdef __VFP_FP__ 104 struct ieee_double { 105 #ifdef __ARMEB__ 106 u_int dbl_sign:1; 107 u_int dbl_exp:11; 108 u_int dbl_frach:20; 109 u_int dbl_fracl; 110 #else /* !__ARMEB__ */ 111 u_int dbl_fracl; 112 u_int dbl_frach:20; 113 u_int dbl_exp:11; 114 u_int dbl_sign:1; 115 #endif /* !__ARMEB__ */ 116 }; 117 #else /* !__VFP_FP__ */ 118 struct ieee_double { 119 u_int dbl_frach:20; 120 u_int dbl_exp:11; 121 u_int dbl_sign:1; 122 u_int dbl_fracl; 123 }; 124 125 struct ieee_ext { 126 u_int ext_exp:15; 127 u_int ext_zero:16; 128 u_int ext_sign:1; 129 u_int ext_frach:31; 130 u_int ext_j:1; 131 u_int ext_fracl; 132 }; 133 #endif /* !__VFP_FP__ */ 134 135 /* 136 * Floats whose exponent is in [1..INFNAN) (of whatever type) are 137 * `normal'. Floats whose exponent is INFNAN are either Inf or NaN. 138 * Floats whose exponent is zero are either zero (iff all fraction 139 * bits are zero) or subnormal values. 140 * 141 * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its 142 * high fraction; if the bit is set, it is a `quiet NaN'. 143 */ 144 #define SNG_EXP_INFNAN 255 145 #define DBL_EXP_INFNAN 2047 146 #ifndef __VFP_FP__ 147 #define EXT_EXP_INFNAN 32767 148 #endif /* !__VFP_FP__ */ 149 150 #if 0 151 #define SNG_QUIETNAN (1 << 22) 152 #define DBL_QUIETNAN (1 << 19) 153 #ifndef __VFP_FP__ 154 #define EXT_QUIETNAN (1 << 15) 155 #endif /* !__VFP_FP__ */ 156 #endif 157 158 /* 159 * Exponent biases. 160 */ 161 #define SNG_EXP_BIAS 127 162 #define DBL_EXP_BIAS 1023 163 #ifndef __VFP_FP__ 164 #define EXT_EXP_BIAS 16383 165 #endif /* !__VFP_FP__ */ 166
Indexes created Sun Oct 12 09:09:55 GMT 2025