#include <stdint.h>
#include <stddef.h>
+#define BITMASK(X) (1 << (X))
+
+uint32_t reflect(uint32_t v, int b) {
+ uint32_t t = v;
+ for (int i = 0; i < b; ++i) {
+ if (t & 1)
+ v |= BITMASK((b - 1) - i);
+ else
+ v &= ~BITMASK((b - 1) - i);
+ t >>= 1;
+ }
+ return v;
+}
+
void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor)
{
crc->order = order;
}
return crc_finish(&crc);
}
+
+// width=8 poly=0x1d, init=0xc7 (0xe3 - WRONG! but it mentioned in MAD datasheet) refin=false refout=false xorout=0x00 name="CRC-8/MIFARE-MAD"
+uint32_t CRC8Mad(uint8_t *buff, size_t size) {
+ crc_t crc;
+ crc_init(&crc, 8, reflect(0x1d, 8), reflect(0xc7, 8), 0);
+ for (int i = 0; i < size; ++i)
+ crc_update(&crc, reflect(buff[i], 8), 8);
+
+ return reflect(crc_finish(&crc), 8);
+}