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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: bits.h,v 1.5 2000/06/17 10:36:06 mdw Exp $ |
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4 | * |
5 | * Portable bit-level manipulation macros |
6 | * |
7 | * (c) 1998 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * mLib is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with mLib; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: bits.h,v $ |
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33 | * Revision 1.5 2000/06/17 10:36:06 mdw |
34 | * Support for 24-bit types. |
35 | * |
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36 | * Revision 1.4 1999/12/10 23:42:04 mdw |
37 | * Change header file guard names. |
38 | * |
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39 | * Revision 1.3 1999/06/20 23:31:52 mdw |
40 | * More portability enhancements. |
41 | * |
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42 | * Revision 1.2 1999/06/17 00:12:46 mdw |
43 | * Improve portability for shift and rotate macros. |
44 | * |
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45 | * Revision 1.1 1999/06/01 09:46:19 mdw |
46 | * New addition: bit manipulation macros. |
47 | * |
48 | */ |
49 | |
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50 | #ifndef MLIB_BITS_H |
51 | #define MLIB_BITS_H |
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52 | |
53 | #ifdef __cplusplus |
54 | extern "C" { |
55 | #endif |
56 | |
57 | /*----- Header files ------------------------------------------------------*/ |
58 | |
59 | #include <limits.h> |
60 | #include <stddef.h> |
61 | |
62 | /*----- Decide on some types ----------------------------------------------*/ |
63 | |
64 | /* --- Decide on a 32-bit type --- * |
65 | * |
66 | * I want a type which is capable of expressing 32-bit numbers. Because some |
67 | * implementations have 64-bit @long@s (infinitely preferable to the abortion |
68 | * that is @long long@), using @unsigned long@ regardless is wasteful. So, |
69 | * if @int@ appears to be good enough, then I'll go with that. |
70 | */ |
71 | |
72 | #if UINT_MAX >= 0xffffffffu |
73 | typedef unsigned int uint32; |
74 | #else |
75 | typedef unsigned long uint32; |
76 | #endif |
77 | |
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78 | /* --- Decide on a 24-bit type --- */ |
79 | |
80 | #if UINT_MAX >= 0x00ffffffu |
81 | typedef unsigned int uint24; |
82 | #else |
83 | typedef unsigned long uint24; |
84 | #endif |
85 | |
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86 | /* --- Decide on 16-bit and 8-bit types --- * |
87 | * |
88 | * This is more for brevity than anything else. |
89 | */ |
90 | |
91 | typedef unsigned short uint16; |
92 | typedef unsigned char octet; |
93 | |
94 | /* --- WARNING! --- * |
95 | * |
96 | * Never lose sight of the fact that the above types may be wider than the |
97 | * names suggest. Some architectures have 32-bit @short@s for example. |
98 | */ |
99 | |
100 | /*----- Macros ------------------------------------------------------------*/ |
101 | |
102 | /* --- Useful masks --- */ |
103 | |
104 | #define MASK8 0xffu |
105 | #define MASK16 0xffffu |
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106 | #define MASK24 0xffffffu |
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107 | #define MASK32 0xffffffffu |
108 | |
109 | /* --- Type coercions --- */ |
110 | |
111 | #define U8(x) ((octet)((x) & MASK8)) |
112 | #define U16(x) ((uint16)((x) & MASK16)) |
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113 | #define U24(x) ((uint24)((x) & MASK24)) |
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114 | #define U32(x) ((uint32)((x) & MASK32)) |
115 | |
116 | /* --- Safe shifting macros --- */ |
117 | |
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118 | #define LSL8(v, s) U8(U8(v) << ((s) & 7u)) |
119 | #define LSR8(v, s) U8(U8(v) >> ((s) & 7u)) |
120 | #define LSL16(v, s) U16(U16(v) << ((s) & 15u)) |
121 | #define LSR16(v, s) U16(U16(v) >> ((s) & 15u)) |
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122 | #define LSL24(v, s) U24(U24(v) << ((s) % 24u)) |
123 | #define LSR24(v, s) U24(U24(v) >> ((s) % 24u)) |
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124 | #define LSL32(v, s) U32(U32(v) << ((s) & 31u)) |
125 | #define LSR32(v, s) U32(U32(v) >> ((s) & 31u)) |
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126 | |
127 | /* --- Rotation macros --- */ |
128 | |
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129 | #define ROL8(v, s) (LSL8((v), (s)) | (LSR8((v), 8u - (s)))) |
130 | #define ROR8(v, s) (LSR8((v), (s)) | (LSL8((v), 8u - (s)))) |
131 | #define ROL16(v, s) (LSL16((v), (s)) | (LSR16((v), 16u - (s)))) |
132 | #define ROR16(v, s) (LSR16((v), (s)) | (LSL16((v), 16u - (s)))) |
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133 | #define ROL24(v, s) (LSL24((v), (s)) | (LSR24((v), 24u - (s)))) |
134 | #define ROR24(v, s) (LSR24((v), (s)) | (LSL24((v), 24u - (s)))) |
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135 | #define ROL32(v, s) (LSL32((v), (s)) | (LSR32((v), 32u - (s)))) |
136 | #define ROR32(v, s) (LSR32((v), (s)) | (LSL32((v), 32u - (s)))) |
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137 | |
138 | /* --- Storage and retrieval --- */ |
139 | |
140 | #define GETBYTE(p, o) (((octet *)(p))[o] & MASK8) |
141 | #define PUTBYTE(p, o, v) (((octet *)(p))[o] = U8((v))) |
142 | |
143 | #define LOAD8(p) (GETBYTE((p), 0)) |
144 | #define STORE8(p, v) (PUTBYTE((p), 0, (v))) |
145 | |
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146 | #define LOAD16_B(p) \ |
147 | (((uint16)GETBYTE((p), 0) << 8) | \ |
148 | ((uint16)GETBYTE((p), 1) << 0)) |
149 | #define LOAD16_L(p) \ |
150 | (((uint16)GETBYTE((p), 0) << 0) | \ |
151 | ((uint16)GETBYTE((p), 1) << 8)) |
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152 | #define LOAD16(p) LOAD16_B((p)) |
153 | |
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154 | #define STORE16_B(p, v) \ |
155 | (PUTBYTE((p), 0, (uint16)(v) >> 8), \ |
156 | PUTBYTE((p), 1, (uint16)(v) >> 0)) |
157 | #define STORE16_L(p, v) \ |
158 | (PUTBYTE((p), 0, (uint16)(v) >> 0), \ |
159 | PUTBYTE((p), 1, (uint16)(v) >> 8)) |
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160 | #define STORE16(p, v) STORE16_B((p), (v)) |
161 | |
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162 | #define LOAD24_B(p) \ |
163 | (((uint24)GETBYTE((p), 0) << 16) | \ |
164 | ((uint24)GETBYTE((p), 1) << 8) | \ |
165 | ((uint24)GETBYTE((p), 2) << 0)) |
166 | #define LOAD24_L(p) \ |
167 | (((uint24)GETBYTE((p), 0) << 0) | \ |
168 | ((uint24)GETBYTE((p), 1) << 8) | \ |
169 | ((uint24)GETBYTE((p), 2) << 16)) |
170 | #define LOAD24(p) LOAD24_B((p)) |
171 | |
172 | #define STORE24_B(p, v) \ |
173 | (PUTBYTE((p), 0, (uint24)(v) >> 16), \ |
174 | PUTBYTE((p), 1, (uint24)(v) >> 8), \ |
175 | PUTBYTE((p), 2, (uint24)(v) >> 0)) |
176 | #define STORE24_L(p, v) \ |
177 | (PUTBYTE((p), 0, (uint24)(v) >> 0), \ |
178 | PUTBYTE((p), 1, (uint24)(v) >> 8), \ |
179 | PUTBYTE((p), 2, (uint24)(v) >> 16)) |
180 | #define STORE24(p, v) STORE24_B((p), (v)) |
181 | |
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182 | #define LOAD32_B(p) \ |
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183 | (((uint32)GETBYTE((p), 0) << 24) | \ |
184 | ((uint32)GETBYTE((p), 1) << 16) | \ |
185 | ((uint32)GETBYTE((p), 2) << 8) | \ |
186 | ((uint32)GETBYTE((p), 3) << 0)) |
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187 | #define LOAD32_L(p) \ |
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188 | (((uint32)GETBYTE((p), 0) << 0) | \ |
189 | ((uint32)GETBYTE((p), 1) << 8) | \ |
190 | ((uint32)GETBYTE((p), 2) << 16) | \ |
191 | ((uint32)GETBYTE((p), 3) << 24)) |
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192 | #define LOAD32(p) LOAD32_B((p)) |
193 | |
194 | #define STORE32_B(p, v) \ |
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195 | (PUTBYTE((p), 0, (uint32)(v) >> 24), \ |
196 | PUTBYTE((p), 1, (uint32)(v) >> 16), \ |
197 | PUTBYTE((p), 2, (uint32)(v) >> 8), \ |
198 | PUTBYTE((p), 3, (uint32)(v) >> 0)) |
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199 | #define STORE32_L(p, v) \ |
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200 | (PUTBYTE((p), 0, (uint32)(v) >> 0), \ |
201 | PUTBYTE((p), 1, (uint32)(v) >> 8), \ |
202 | PUTBYTE((p), 2, (uint32)(v) >> 16), \ |
203 | PUTBYTE((p), 3, (uint32)(v) >> 24)) |
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204 | #define STORE32(p, v) STORE32_B((p), (v)) |
205 | |
206 | /*----- That's all, folks -------------------------------------------------*/ |
207 | |
208 | #ifdef __cplusplus |
209 | } |
210 | #endif |
211 | |
212 | #endif |