| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: bits.h,v 1.3 1999/06/20 23:31:52 mdw Exp $ |
| 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 $ |
| 33 | * Revision 1.3 1999/06/20 23:31:52 mdw |
| 34 | * More portability enhancements. |
| 35 | * |
| 36 | * Revision 1.2 1999/06/17 00:12:46 mdw |
| 37 | * Improve portability for shift and rotate macros. |
| 38 | * |
| 39 | * Revision 1.1 1999/06/01 09:46:19 mdw |
| 40 | * New addition: bit manipulation macros. |
| 41 | * |
| 42 | */ |
| 43 | |
| 44 | #ifndef BITS_H |
| 45 | #define BITS_H |
| 46 | |
| 47 | #ifdef __cplusplus |
| 48 | extern "C" { |
| 49 | #endif |
| 50 | |
| 51 | /*----- Header files ------------------------------------------------------*/ |
| 52 | |
| 53 | #include <limits.h> |
| 54 | #include <stddef.h> |
| 55 | |
| 56 | /*----- Decide on some types ----------------------------------------------*/ |
| 57 | |
| 58 | /* --- Decide on a 32-bit type --- * |
| 59 | * |
| 60 | * I want a type which is capable of expressing 32-bit numbers. Because some |
| 61 | * implementations have 64-bit @long@s (infinitely preferable to the abortion |
| 62 | * that is @long long@), using @unsigned long@ regardless is wasteful. So, |
| 63 | * if @int@ appears to be good enough, then I'll go with that. |
| 64 | */ |
| 65 | |
| 66 | #if UINT_MAX >= 0xffffffffu |
| 67 | typedef unsigned int uint32; |
| 68 | #else |
| 69 | typedef unsigned long uint32; |
| 70 | #endif |
| 71 | |
| 72 | /* --- Decide on 16-bit and 8-bit types --- * |
| 73 | * |
| 74 | * This is more for brevity than anything else. |
| 75 | */ |
| 76 | |
| 77 | typedef unsigned short uint16; |
| 78 | typedef unsigned char octet; |
| 79 | |
| 80 | /* --- WARNING! --- * |
| 81 | * |
| 82 | * Never lose sight of the fact that the above types may be wider than the |
| 83 | * names suggest. Some architectures have 32-bit @short@s for example. |
| 84 | */ |
| 85 | |
| 86 | /*----- Macros ------------------------------------------------------------*/ |
| 87 | |
| 88 | /* --- Useful masks --- */ |
| 89 | |
| 90 | #define MASK8 0xffu |
| 91 | #define MASK16 0xffffu |
| 92 | #define MASK32 0xffffffffu |
| 93 | |
| 94 | /* --- Type coercions --- */ |
| 95 | |
| 96 | #define U8(x) ((octet)((x) & MASK8)) |
| 97 | #define U16(x) ((uint16)((x) & MASK16)) |
| 98 | #define U32(x) ((uint32)((x) & MASK32)) |
| 99 | |
| 100 | /* --- Safe shifting macros --- */ |
| 101 | |
| 102 | #define LSL8(v, s) U8(U8(v) << ((s) & 7u)) |
| 103 | #define LSR8(v, s) U8(U8(v) >> ((s) & 7u)) |
| 104 | #define LSL16(v, s) U16(U16(v) << ((s) & 15u)) |
| 105 | #define LSR16(v, s) U16(U16(v) >> ((s) & 15u)) |
| 106 | #define LSL32(v, s) U32(U32(v) << ((s) & 31u)) |
| 107 | #define LSR32(v, s) U32(U32(v) >> ((s) & 31u)) |
| 108 | |
| 109 | /* --- Rotation macros --- */ |
| 110 | |
| 111 | #define ROL8(v, s) (LSL8((v), (s)) | (LSR8((v), 8u - (s)))) |
| 112 | #define ROR8(v, s) (LSR8((v), (s)) | (LSL8((v), 8u - (s)))) |
| 113 | #define ROL16(v, s) (LSL16((v), (s)) | (LSR16((v), 16u - (s)))) |
| 114 | #define ROR16(v, s) (LSR16((v), (s)) | (LSL16((v), 16u - (s)))) |
| 115 | #define ROL32(v, s) (LSL32((v), (s)) | (LSR32((v), 32u - (s)))) |
| 116 | #define ROR32(v, s) (LSR32((v), (s)) | (LSL32((v), 32u - (s)))) |
| 117 | |
| 118 | /* --- Storage and retrieval --- */ |
| 119 | |
| 120 | #define GETBYTE(p, o) (((octet *)(p))[o] & MASK8) |
| 121 | #define PUTBYTE(p, o, v) (((octet *)(p))[o] = U8((v))) |
| 122 | |
| 123 | #define LOAD8(p) (GETBYTE((p), 0)) |
| 124 | #define STORE8(p, v) (PUTBYTE((p), 0, (v))) |
| 125 | |
| 126 | #define LOAD16_B(p) \ |
| 127 | (((uint16)GETBYTE((p), 0) << 8) | \ |
| 128 | ((uint16)GETBYTE((p), 1) << 0)) |
| 129 | #define LOAD16_L(p) \ |
| 130 | (((uint16)GETBYTE((p), 0) << 0) | \ |
| 131 | ((uint16)GETBYTE((p), 1) << 8)) |
| 132 | #define LOAD16(p) LOAD16_B((p)) |
| 133 | |
| 134 | #define STORE16_B(p, v) \ |
| 135 | (PUTBYTE((p), 0, (uint16)(v) >> 8), \ |
| 136 | PUTBYTE((p), 1, (uint16)(v) >> 0)) |
| 137 | #define STORE16_L(p, v) \ |
| 138 | (PUTBYTE((p), 0, (uint16)(v) >> 0), \ |
| 139 | PUTBYTE((p), 1, (uint16)(v) >> 8)) |
| 140 | #define STORE16(p, v) STORE16_B((p), (v)) |
| 141 | |
| 142 | #define LOAD32_B(p) \ |
| 143 | (((uint32)GETBYTE((p), 0) << 24) | \ |
| 144 | ((uint32)GETBYTE((p), 1) << 16) | \ |
| 145 | ((uint32)GETBYTE((p), 2) << 8) | \ |
| 146 | ((uint32)GETBYTE((p), 3) << 0)) |
| 147 | #define LOAD32_L(p) \ |
| 148 | (((uint32)GETBYTE((p), 0) << 0) | \ |
| 149 | ((uint32)GETBYTE((p), 1) << 8) | \ |
| 150 | ((uint32)GETBYTE((p), 2) << 16) | \ |
| 151 | ((uint32)GETBYTE((p), 3) << 24)) |
| 152 | #define LOAD32(p) LOAD32_B((p)) |
| 153 | |
| 154 | #define STORE32_B(p, v) \ |
| 155 | (PUTBYTE((p), 0, (uint32)(v) >> 24), \ |
| 156 | PUTBYTE((p), 1, (uint32)(v) >> 16), \ |
| 157 | PUTBYTE((p), 2, (uint32)(v) >> 8), \ |
| 158 | PUTBYTE((p), 3, (uint32)(v) >> 0)) |
| 159 | #define STORE32_L(p, v) \ |
| 160 | (PUTBYTE((p), 0, (uint32)(v) >> 0), \ |
| 161 | PUTBYTE((p), 1, (uint32)(v) >> 8), \ |
| 162 | PUTBYTE((p), 2, (uint32)(v) >> 16), \ |
| 163 | PUTBYTE((p), 3, (uint32)(v) >> 24)) |
| 164 | #define STORE32(p, v) STORE32_B((p), (v)) |
| 165 | |
| 166 | /*----- That's all, folks -------------------------------------------------*/ |
| 167 | |
| 168 | #ifdef __cplusplus |
| 169 | } |
| 170 | #endif |
| 171 | |
| 172 | #endif |