X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/22f4dca88cc008287b1ef01bb4da0d46cbcf76d1..4b555c8dc09231a1a0b9b1f84a778b709fb965b1:/common/crc.c?ds=sidebyside diff --git a/common/crc.c b/common/crc.c index 2f11f5f4..f9a15234 100644 --- a/common/crc.c +++ b/common/crc.c @@ -29,23 +29,22 @@ void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, u } void crc_clear(crc_t *crc) { + crc->state = crc->initial_value & crc->mask; if (crc->refin) crc->state = reflect(crc->state, crc->order); } -void crc_update(crc_t *crc, uint32_t indata, int data_width){ - - //reflected - if (crc->refin) indata = reflect(indata, data_width); +void crc_update2(crc_t *crc, uint32_t data, int data_width){ + + if (crc->refin) + data = reflect(data, data_width); // Bring the next byte into the remainder. - crc->state ^= indata << (crc->order - data_width); + crc->state ^= data << (crc->order - data_width); - for( uint8_t bit = data_width; bit > 0; --bit) { - - - // Try to divide the current data bit. + for( uint8_t bit = data_width; bit > 0; --bit) { + if (crc->state & crc->topbit) crc->state = (crc->state << 1) ^ crc->polynom; else @@ -53,9 +52,10 @@ void crc_update(crc_t *crc, uint32_t indata, int data_width){ } } -void crc_update2(crc_t *crc, uint32_t data, int data_width) +void crc_update(crc_t *crc, uint32_t data, int data_width) { - if (crc->refin) data = reflect(data, data_width); + if (crc->refin) + data = reflect(data, data_width); int i; for(i=0; istate; if (crc->refout) val = reflect(val, crc->order); @@ -96,7 +95,7 @@ uint32_t CRC8Maxim(uint8_t *buff, size_t size) { crc_t crc; crc_init_ref(&crc, 8, 0x31, 0, 0, TRUE, TRUE); for ( int i=0; i < size; ++i) - crc_update(&crc, buff[i], 8); + crc_update2(&crc, buff[i], 8); return crc_finish(&crc); } @@ -115,7 +114,7 @@ uint32_t CRC8Legic(uint8_t *buff, size_t size) { crc_t crc; crc_init_ref(&crc, 8, 0x63, 0x55, 0, TRUE, TRUE); for ( int i = 0; i < size; ++i) - crc_update(&crc, buff[i], 8); + crc_update2(&crc, buff[i], 8); return reflect(crc_finish(&crc), 8); } @@ -139,7 +138,7 @@ uint32_t CRC16_DNP(uint8_t *buff, size_t size) { crc_t crc; crc_init_ref(&crc, 16, 0x3d65, 0, 0xffff, TRUE, TRUE); for ( int i=0; i < size; ++i) - crc_update(&crc, buff[i], 8); + crc_update2(&crc, buff[i], 8); return BSWAP_16(crc_finish(&crc)); }