79 lines
2.1 KiB
C
79 lines
2.1 KiB
C
/*
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* crc.h -- CRC routines
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*
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* Copyright (C) 2008 Hugo Villeneuve <hugo@hugovil.com>
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*
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* Based on dv-boot, original copyright follows:
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* Copyright (c) 2007 Sergey Kubushin <ksi@koi8.net>
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*
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* Based on TI DaVinci Flash and Boot Utilities, original copyright follows:
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* Copyright 2008 Texas Instruments, Inc. <www.ti.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include <stdint.h>
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#include <string.h> /* For size_t */
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#define CRC_TABLE_ELEMENTS 256
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#define DAVINCI_CRC_POLY 0x04C11DB7
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static uint32_t crc32_table[CRC_TABLE_ELEMENTS];
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static uint32_t
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reflect_num(uint32_t in_val, uint32_t num)
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{
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uint32_t i;
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uint32_t out_val = 0x0;
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for (i = 1; i < (num + 1); i++) {
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out_val |= (uint32_t)(((in_val & 0x1)) << (num - i));
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in_val >>= 1;
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}
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return out_val;
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}
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/* Build a reflected CRC-32 table (for standard CRC-32 algorithm) */
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void
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crc32_dv_build_table(void)
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{
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uint32_t i, j, crc_accum;
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for (i = 0; i < CRC_TABLE_ELEMENTS; i++) {
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crc_accum = reflect_num(i, 8) << (32 - 8);
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for (j = 0; j < 8; j++) {
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if ((crc_accum & 0x80000000) != 0x00000000)
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crc_accum = (crc_accum << 1) ^ DAVINCI_CRC_POLY;
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else
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crc_accum = (crc_accum << 1);
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crc32_table[i] = reflect_num(crc_accum, 32);
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}
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}
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}
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/* Compute CRC32 checksum */
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uint32_t
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crc32_dv_compute(uint8_t *data, size_t size)
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{
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uint32_t crc32 = 0xFFFFFFFF;
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while (size-- > 0)
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crc32 = crc32_table[(crc32 ^ *data++) & 0xFF] ^ (crc32 >> 8);
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return crc32;
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}
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