diff options
author | Artem Bityutskiy <Artem.Bityutskiy@nokia.com> | 2008-02-19 14:54:17 +0200 |
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committer | Artem Bityutskiy <Artem.Bityutskiy@nokia.com> | 2008-02-19 16:41:16 +0200 |
commit | 86dd9696d3a1acb036d65909d93d73455b8aed3a (patch) | |
tree | 9e8bb6797b3bebd0bf83ae1fab2151a6dfeafe6a /ubi-utils/src/crc32.c | |
parent | ef644090223e5983ca2492850354c1390e3368d1 (diff) |
Revert ubi-tools changes
Restore ubi tools to their "original" state, which means to
the state they were before I stareted cleaning them up.
Instead, create a "new-utils" subdirectory and move my work
there.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Diffstat (limited to 'ubi-utils/src/crc32.c')
-rw-r--r-- | ubi-utils/src/crc32.c | 156 |
1 files changed, 72 insertions, 84 deletions
diff --git a/ubi-utils/src/crc32.c b/ubi-utils/src/crc32.c index 6b1e50c..666e217 100644 --- a/ubi-utils/src/crc32.c +++ b/ubi-utils/src/crc32.c @@ -1,95 +1,83 @@ /* - * COPYRIGHT (C) 1986 Gary S. Brown. You may use this program, or - * code or tables extracted from it, as desired without restriction. + * Copyright (c) International Business Machines Corp., 2006 * - * First, the polynomial itself and its table of feedback terms. The - * polynomial is - * X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0 + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. * - * Note that we take it "backwards" and put the highest-order term in - * the lowest-order bit. The X^32 term is "implied"; the LSB is the - * X^31 term, etc. The X^0 term (usually shown as "+1") results in - * the MSB being 1 + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU General Public License for more details. * - * Note that the usual hardware shift register implementation, which - * is what we're using (we're merely optimizing it by doing eight-bit - * chunks at a time) shifts bits into the lowest-order term. In our - * implementation, that means shifting towards the right. Why do we - * do it this way? Because the calculated CRC must be transmitted in - * order from highest-order term to lowest-order term. UARTs transmit - * characters in order from LSB to MSB. By storing the CRC this way - * we hand it to the UART in the order low-byte to high-byte; the UART - * sends each low-bit to hight-bit; and the result is transmission bit - * by bit from highest- to lowest-order term without requiring any bit - * shuffling on our part. Reception works similarly + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * - * The feedback terms table consists of 256, 32-bit entries. Notes + * Author: Thomas Gleixner + */ + +/* + * CRC32 functions * - * The table can be generated at runtime if desired; code to do so - * is shown later. It might not be obvious, but the feedback - * terms simply represent the results of eight shift/xor opera - * tions for all combinations of data and CRC register values + * Can be compiled as seperate object, but is included into the ipl source + * so gcc can inline the functions. We optimize for size so the omission of + * the function frame is helpful. * - * The values must be right-shifted by eight bits by the "updcrc - * logic; the shift must be unsigned (bring in zeroes). On some - * hardware you could probably optimize the shift in assembler by - * using byte-swap instructions - * polynomial $edb88320 */ #include <stdint.h> +#include <crc32.h> + +/* CRC polynomial */ +#define CRC_POLY 0xEDB88320 + +/** + * init_crc32_table - Initialize crc table + * + * @table: pointer to the CRC table which must be initialized + * + * Create CRC32 table for given polynomial. The table is created with + * the lowest order term in the highest order bit. So the x^32 term + * has to implied in the crc calculation function. + */ +void init_crc32_table(uint32_t *table) +{ + uint32_t crc; + int i, j; + + for (i = 0; i < 256; i++) { + crc = i; + for (j = 8; j > 0; j--) { + if (crc & 1) + crc = (crc >> 1) ^ CRC_POLY; + else + crc >>= 1; + } + table[i] = crc; + } +} + +/** + * clc_crc32 - Calculate CRC32 over a buffer + * + * @table: pointer to the CRC table + * @crc: initial crc value + * @buf: pointer to the buffer + * @len: number of bytes to calc + * + * Returns the updated crc value. + * + * The algorithm resembles a hardware shift register, but calculates 8 + * bit at once. + */ +uint32_t clc_crc32(uint32_t *table, uint32_t crc, void *buf, + int len) +{ + const unsigned char *p = buf; -const uint32_t crc32_table[256] = { - 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L, - 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L, - 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, - 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, - 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L, - 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, - 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, - 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL, - 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L, - 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL, - 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, - 0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L, - 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L, - 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL, - 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, - 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L, - 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL, - 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L, - 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, - 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L, - 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL, - 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L, - 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L, - 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL, - 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L, - 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L, - 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L, - 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L, - 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L, - 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL, - 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, - 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L, - 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L, - 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL, - 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL, - 0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L, - 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL, - 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L, - 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, - 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L, - 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL, - 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L, - 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, - 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL, - 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L, - 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L, - 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, - 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L, - 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L, - 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L, - 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, - 0x2d02ef8dL -}; + while(--len >= 0) + crc = table[(crc ^ *p++) & 0xff] ^ (crc >> 8); + return crc; +} |