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bd20f8f478
I have kept whatever copyright notices exist. Please add your own copyright notice if you have made any nontrivial changes or additions to the code. There are several files without any attribution, currently.
43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
//-----------------------------------------------------------------------------
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// This code is licensed to you under the terms of the GNU GPL, version 2 or,
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// at your option, any later version. See the LICENSE.txt file for the text of
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// the license.
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//-----------------------------------------------------------------------------
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// Generic CRC calculation code.
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//-----------------------------------------------------------------------------
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#include "crc.h"
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void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor)
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{
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crc->order = order;
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crc->polynom = polynom;
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crc->initial_value = initial_value;
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crc->final_xor = final_xor;
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crc->mask = (1L<<order)-1;
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crc_clear(crc);
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}
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void crc_update(crc_t *crc, uint32_t data, int data_width)
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{
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int i;
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for(i=0; i<data_width; i++) {
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int oldstate = crc->state;
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crc->state = crc->state >> 1;
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if( (oldstate^data) & 1 ) {
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crc->state ^= crc->polynom;
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}
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data >>= 1;
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}
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}
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void crc_clear(crc_t *crc)
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{
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crc->state = crc->initial_value & crc->mask;
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}
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uint32_t crc_finish(crc_t *crc)
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{
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return ( crc->state ^ crc->final_xor ) & crc->mask;
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}
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