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review.blissroms.org / platform_bionic / 405b8029a6888f386adf3512113a33546141d1c8 / . / libc / arch-mips / include / machine / ieee.h
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Raghu Gandham405b8022012-07-25 18:16:42 -0700[diff] [blame^]1/* $OpenBSD: ieee.h,v 1.4 2010/01/23 19:11:21 miod 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. It does *not* define (yet?) any of the rounding
46 * mode bits, exceptions, and so forth.
47 */
48
49/*
50 * Define the number of bits in each fraction and exponent.
51 *
52 * k k+1
53 * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented
54 *
55 * (-exp_bias+1)
56 * as fractions that look like 0.fffff x 2 . This means that
57 *
58 * -126
59 * the number 0.10000 x 2 , for instance, is the same as the normalized
60 *
61 * -127 -128
62 * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero
63 *
64 * -129
65 * in the fraction; to represent 2 , we need two, and so on. This
66 *
67 * (-exp_bias-fracbits+1)
68 * implies that the smallest denormalized number is 2
69 *
70 * for whichever format we are talking about: for single precision, for
71 *
72 * -126 -149
73 * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and
74 *
75 * -149 == -127 - 23 + 1.
76 */
77#define SNG_EXPBITS 8
78#define SNG_FRACBITS 23
79
80#define DBL_EXPBITS 11
81#define DBL_FRACHBITS 20
82#define DBL_FRACLBITS 32
83#define DBL_FRACBITS 52
84
85#define EXT_EXPBITS 15
86#define EXT_FRACHBITS 16
87#define EXT_FRACHMBITS 32
88#define EXT_FRACLMBITS 32
89#define EXT_FRACLBITS 32
90#define EXT_FRACBITS 112
91
92#define EXT_IMPLICIT_NBIT
93
94#define EXT_TO_ARRAY32(p, a) do { \
95 (a)[0] = (uint32_t)(p)->ext_fracl; \
96 (a)[1] = (uint32_t)(p)->ext_fraclm; \
97 (a)[2] = (uint32_t)(p)->ext_frachm; \
98 (a)[3] = (uint32_t)(p)->ext_frach; \
99} while(0)
100
101struct ieee_single {
102#ifdef __MIPSEB__
103 u_int sng_sign:1;
104 u_int sng_exp:8;
105 u_int sng_frac:23;
106#else
107 u_int sng_frac:23;
108 u_int sng_exp:8;
109 u_int sng_sign:1;
110#endif
111};
112
113struct ieee_double {
114#ifdef __MIPSEB__
115 u_int dbl_sign:1;
116 u_int dbl_exp:11;
117 u_int dbl_frach:20;
118 u_int dbl_fracl;
119#else
120 u_int dbl_fracl;
121 u_int dbl_frach:20;
122 u_int dbl_exp:11;
123 u_int dbl_sign:1;
124#endif
125};
126
127struct ieee_ext {
128#ifdef __MIPSEB__
129 u_int ext_sign:1;
130 u_int ext_exp:15;
131 u_int ext_frach:16;
132 u_int ext_frachm;
133 u_int ext_fraclm;
134 u_int ext_fracl;
135#else
136 u_int ext_fracl;
137 u_int ext_fraclm;
138 u_int ext_frachm;
139 u_int ext_frach:16;
140 u_int ext_exp:15;
141 u_int ext_sign:1;
142#endif
143};
144
145/*
146 * Floats whose exponent is in [1..INFNAN) (of whatever type) are
147 * `normal'. Floats whose exponent is INFNAN are either Inf or NaN.
148 * Floats whose exponent is zero are either zero (iff all fraction
149 * bits are zero) or subnormal values.
150 *
151 * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
152 * high fraction; if the bit is set, it is a `quiet NaN'.
153 */
154#define SNG_EXP_INFNAN 255
155#define DBL_EXP_INFNAN 2047
156#define EXT_EXP_INFNAN 32767
157
158#if 0
159#define SNG_QUIETNAN (1 << 22)
160#define DBL_QUIETNAN (1 << 19)
161#define EXT_QUIETNAN (1 << 15)
162#endif
163
164/*
165 * Exponent biases.
166 */
167#define SNG_EXP_BIAS 127
168#define DBL_EXP_BIAS 1023
169#define EXT_EXP_BIAS 16383