Annotation of sys/arch/arm/include/ieee.h, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: ieee.h,v 1.1 2004/02/01 05:09:49 drahn Exp $ */
! 2: /* $NetBSD: ieee.h,v 1.2 2001/02/21 17:43:50 bjh21 Exp $ */
! 3:
! 4: /*
! 5: * Copyright (c) 1992, 1993
! 6: * The Regents of the University of California. All rights reserved.
! 7: *
! 8: * This software was developed by the Computer Systems Engineering group
! 9: * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
! 10: * contributed to Berkeley.
! 11: *
! 12: * All advertising materials mentioning features or use of this software
! 13: * must display the following acknowledgement:
! 14: * This product includes software developed by the University of
! 15: * California, Lawrence Berkeley Laboratory.
! 16: *
! 17: * Redistribution and use in source and binary forms, with or without
! 18: * modification, are permitted provided that the following conditions
! 19: * are met:
! 20: * 1. Redistributions of source code must retain the above copyright
! 21: * notice, this list of conditions and the following disclaimer.
! 22: * 2. Redistributions in binary form must reproduce the above copyright
! 23: * notice, this list of conditions and the following disclaimer in the
! 24: * documentation and/or other materials provided with the distribution.
! 25: * 3. All advertising materials mentioning features or use of this software
! 26: * must display the following acknowledgement:
! 27: * This product includes software developed by the University of
! 28: * California, Berkeley and its contributors.
! 29: * 4. Neither the name of the University nor the names of its contributors
! 30: * may be used to endorse or promote products derived from this software
! 31: * without specific prior written permission.
! 32: *
! 33: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 34: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 35: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 36: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 37: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 38: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 39: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 40: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 41: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 42: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 43: * SUCH DAMAGE.
! 44: *
! 45: * @(#)ieee.h 8.1 (Berkeley) 6/11/93
! 46: */
! 47:
! 48: /*
! 49: * ieee.h defines the machine-dependent layout of the machine's IEEE
! 50: * floating point.
! 51: */
! 52:
! 53: /*
! 54: * Define the number of bits in each fraction and exponent.
! 55: *
! 56: * k k+1
! 57: * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented
! 58: *
! 59: * (-exp_bias+1)
! 60: * as fractions that look like 0.fffff x 2 . This means that
! 61: *
! 62: * -126
! 63: * the number 0.10000 x 2 , for instance, is the same as the normalized
! 64: *
! 65: * -127 -128
! 66: * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero
! 67: *
! 68: * -129
! 69: * in the fraction; to represent 2 , we need two, and so on. This
! 70: *
! 71: * (-exp_bias-fracbits+1)
! 72: * implies that the smallest denormalized number is 2
! 73: *
! 74: * for whichever format we are talking about: for single precision, for
! 75: *
! 76: * -126 -149
! 77: * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and
! 78: *
! 79: * -149 == -127 - 23 + 1.
! 80: */
! 81:
! 82: /*
! 83: * The ARM has two sets of FP data formats. The FPA supports 32-bit, 64-bit
! 84: * and 96-bit IEEE formats, with the words in big-endian order. VFP supports
! 85: * 32-bin and 64-bit IEEE formats with the words in the CPU's native byte
! 86: * order.
! 87: *
! 88: * The FPA also has two packed decimal formats, but we ignore them here.
! 89: */
! 90:
! 91: #define SNG_EXPBITS 8
! 92: #define SNG_FRACBITS 23
! 93:
! 94: #define DBL_EXPBITS 11
! 95: #define DBL_FRACBITS 52
! 96:
! 97: #ifndef __VFP_FP__
! 98: #define E80_EXPBITS 15
! 99: #define E80_FRACBITS 64
! 100:
! 101: #define EXT_EXPBITS 15
! 102: #define EXT_FRACBITS 112
! 103: #endif
! 104:
! 105: struct ieee_single {
! 106: u_int sng_frac:23;
! 107: u_int sng_exponent:8;
! 108: u_int sng_sign:1;
! 109: };
! 110:
! 111: #ifdef __VFP_FP__
! 112: struct ieee_double {
! 113: #ifdef __ARMEB__
! 114: u_int dbl_sign:1;
! 115: u_int dbl_exp:11;
! 116: u_int dbl_frach:20;
! 117: u_int dbl_fracl;
! 118: #else /* !__ARMEB__ */
! 119: u_int dbl_fracl;
! 120: u_int dbl_frach:20;
! 121: u_int dbl_exp:11;
! 122: u_int dbl_sign:1;
! 123: #endif /* !__ARMEB__ */
! 124: };
! 125: #else /* !__VFP_FP__ */
! 126: struct ieee_double {
! 127: u_int dbl_frach:20;
! 128: u_int dbl_exp:11;
! 129: u_int dbl_sign:1;
! 130: u_int dbl_fracl;
! 131: };
! 132:
! 133: union ieee_double_u {
! 134: double dblu_d;
! 135: struct ieee_double dblu_dbl;
! 136: };
! 137:
! 138:
! 139: struct ieee_e80 {
! 140: u_int e80_exp:15;
! 141: u_int e80_zero:16;
! 142: u_int e80_sign:1;
! 143: u_int e80_frach:31;
! 144: u_int e80_j:1;
! 145: u_int e80_fracl;
! 146: };
! 147:
! 148: struct ieee_ext {
! 149: u_int ext_frach:16;
! 150: u_int ext_exp:15;
! 151: u_int ext_sign:1;
! 152: u_int ext_frachm;
! 153: u_int ext_fraclm;
! 154: u_int ext_fracl;
! 155: };
! 156: #endif /* !__VFP_FP__ */
! 157:
! 158: /*
! 159: * Floats whose exponent is in [1..INFNAN) (of whatever type) are
! 160: * `normal'. Floats whose exponent is INFNAN are either Inf or NaN.
! 161: * Floats whose exponent is zero are either zero (iff all fraction
! 162: * bits are zero) or subnormal values.
! 163: *
! 164: * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
! 165: * high fraction; if the bit is set, it is a `quiet NaN'.
! 166: */
! 167: #define SNG_EXP_INFNAN 255
! 168: #define DBL_EXP_INFNAN 2047
! 169: #ifndef __VFP_FP__
! 170: #define E80_EXP_INFNAN 32767
! 171: #define EXT_EXP_INFNAN 32767
! 172: #endif /* !__VFP_FP__ */
! 173:
! 174: #if 0
! 175: #define SNG_QUIETNAN (1 << 22)
! 176: #define DBL_QUIETNAN (1 << 19)
! 177: #ifndef __VFP_FP__
! 178: #define E80_QUIETNAN (1 << 15)
! 179: #define EXT_QUIETNAN (1 << 15)
! 180: #endif /* !__VFP_FP__ */
! 181: #endif
! 182:
! 183: /*
! 184: * Exponent biases.
! 185: */
! 186: #define SNG_EXP_BIAS 127
! 187: #define DBL_EXP_BIAS 1023
! 188: #ifndef __VFP_FP__
! 189: #define E80_EXP_BIAS 16383
! 190: #define EXT_EXP_BIAS 16383
! 191: #endif /* !__VFP_FP__ */
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