Annotation of sys/arch/m88k/include/ieee.h, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: ieee.h,v 1.2 2006/05/04 19:28:43 miod Exp $ */
! 2: /*
! 3: * Copyright (c) 1992, 1993
! 4: * The Regents of the University of California. All rights reserved.
! 5: *
! 6: * This software was developed by the Computer Systems Engineering group
! 7: * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
! 8: * contributed to Berkeley.
! 9: *
! 10: * All advertising materials mentioning features or use of this software
! 11: * must display the following acknowledgement:
! 12: * This product includes software developed by the University of
! 13: * California, Lawrence Berkeley Laboratory.
! 14: *
! 15: * Redistribution and use in source and binary forms, with or without
! 16: * modification, are permitted provided that the following conditions
! 17: * are met:
! 18: * 1. Redistributions of source code must retain the above copyright
! 19: * notice, this list of conditions and the following disclaimer.
! 20: * 2. Redistributions in binary form must reproduce the above copyright
! 21: * notice, this list of conditions and the following disclaimer in the
! 22: * documentation and/or other materials provided with the distribution.
! 23: * 3. Neither the name of the University nor the names of its contributors
! 24: * may be used to endorse or promote products derived from this software
! 25: * without specific prior written permission.
! 26: *
! 27: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 28: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 29: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 30: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 31: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 32: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 33: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 34: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 35: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 36: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 37: * SUCH DAMAGE.
! 38: *
! 39: * @(#)ieee.h 8.1 (Berkeley) 6/11/93
! 40: */
! 41:
! 42: /*
! 43: * ieee.h defines the machine-dependent layout of the machine's IEEE
! 44: * floating point. It does *not* define (yet?) any of the rounding
! 45: * mode bits, exceptions, and so forth.
! 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: #define SNG_EXPBITS 8
! 77: #define SNG_FRACBITS 23
! 78:
! 79: #define DBL_EXPBITS 11
! 80: #define DBL_FRACBITS 52
! 81:
! 82: #define EXT_EXPBITS 15
! 83: #define EXT_FRACBITS 64
! 84:
! 85: struct ieee_single {
! 86: u_int sng_sign:1;
! 87: u_int sng_exp:8;
! 88: u_int sng_frac:23;
! 89: };
! 90:
! 91: struct ieee_double {
! 92: u_int dbl_sign:1;
! 93: u_int dbl_exp:11;
! 94: u_int dbl_frach:20;
! 95: u_int dbl_fracl;
! 96: };
! 97:
! 98: struct ieee_ext {
! 99: u_int ext_sign:1;
! 100: u_int ext_exp:15;
! 101: u_int ext_lead:1;
! 102: u_int ext_frach:31;
! 103: u_int ext_fracl;
! 104: };
! 105:
! 106: /*
! 107: * Floats whose exponent is in [1..INFNAN) (of whatever type) are
! 108: * `normal'. Floats whose exponent is INFNAN are either Inf or NaN.
! 109: * Floats whose exponent is zero are either zero (iff all fraction
! 110: * bits are zero) or subnormal values.
! 111: *
! 112: * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
! 113: * high fraction; if the bit is set, it is a `quiet NaN'.
! 114: */
! 115: #define SNG_EXP_INFNAN 255
! 116: #define DBL_EXP_INFNAN 2047
! 117: #define EXT_EXP_INFNAN 32767
! 118:
! 119: #if 0
! 120: #define SNG_QUIETNAN (1 << 22)
! 121: #define DBL_QUIETNAN (1 << 19)
! 122: #define EXT_QUIETNAN (1 << 30)
! 123: #endif
! 124:
! 125: /*
! 126: * Exponent biases.
! 127: */
! 128: #define SNG_EXP_BIAS 127
! 129: #define DBL_EXP_BIAS 1023
! 130: #define EXT_EXP_BIAS 16383
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