save 2.3K flash-memory by avoiding a single floating point operation (#630)

[proxmark3-svn] / common / crc.c

diff --git a/common/crc.c b/common/crc.c
index 90d57afab6a56c90bdfbc4b8840b718ffea247cf..0c73474fa75888bf40878f4b41d6269e7f74510c 100644 (file)
--- a/common/crc.c
+++ b/common/crc.c
@@ -5,8 +5,9 @@
 //-----------------------------------------------------------------------------
 // Generic CRC calculation code.
 //-----------------------------------------------------------------------------
 //-----------------------------------------------------------------------------
 // Generic CRC calculation code.
 //-----------------------------------------------------------------------------

-

 #include "crc.h"
 #include "crc.h"

+#include <stdint.h>
+#include <stddef.h>

 
 void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor)
 {
 
 void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor)
 {


@@ -40,3 +41,16 @@ uint32_t crc_finish(crc_t *crc)
 {
        return ( crc->state ^ crc->final_xor ) & crc->mask;
 }
 {
        return ( crc->state ^ crc->final_xor ) & crc->mask;
 }

+
+//credits to iceman
+uint32_t CRC8Maxim(uint8_t *buff, size_t size) 
+{
+       crc_t crc;
+       crc_init(&crc, 9, 0x8c, 0x00, 0x00);
+       crc_clear(&crc);
+
+       for (size_t i=0; i < size; ++i){
+               crc_update(&crc, buff[i], 8);
+       }
+       return crc_finish(&crc);
+}