xref: /aosp_15_r20/external/coreboot/src/lib/crc_byte.c (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c) 
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 
3 #include <crc_byte.h>
4 
crc7_byte(uint8_t prev_crc,uint8_t data)5 uint8_t crc7_byte(uint8_t prev_crc, uint8_t data)
6 {
7 	const uint8_t g = 0x89;
8 	prev_crc ^= data;
9 	for (int i = 0; i < 8; i++) {
10 		if (prev_crc & 0x80)
11 			prev_crc ^= g;
12 		prev_crc <<= 1;
13 	}
14 	return prev_crc;
15 }
16 
crc16_byte(uint16_t prev_crc,uint8_t data)17 uint16_t crc16_byte(uint16_t prev_crc, uint8_t data)
18 {
19 	prev_crc  = (uint8_t)(prev_crc >> 8)|(prev_crc << 8);
20 	prev_crc ^=  data;
21 	prev_crc ^= (uint8_t)(prev_crc & 0xff) >> 4;
22 	prev_crc ^= (prev_crc << 8) << 4;
23 	prev_crc ^= ((prev_crc & 0xff) << 4) << 1;
24 	return prev_crc;
25 }
26 
crc32_byte(uint32_t prev_crc,uint8_t data)27 uint32_t crc32_byte(uint32_t prev_crc, uint8_t data)
28 {
29 	prev_crc ^= (uint32_t)data << 24;
30 
31 	for (int i = 0; i < 8; i++) {
32 		if ((prev_crc & 0x80000000UL) != 0)
33 			prev_crc = ((prev_crc << 1) ^ 0x04C11DB7UL);
34 		else
35 			prev_crc <<= 1;
36 	}
37 
38 	return prev_crc;
39 }
40