Annotation of sys/arch/arm/include/ieee.h, Revision 1.1.1.1
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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