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#include "stdalg.h"
#ifdef STDALGO_CRC7
unsigned char crc7(unsigned char* bytes, unsigned char size)
{
register unsigned char val = 0; // last cycles value
register unsigned char cb; // current byte.
unsigned char i;
for(i=0; i<=size; i++)
{
cb = bytes[i];
int q = (i==size) ? 7 : 8; // counter
do
{
val <<= 1;
if(cb & 0x80) // check MSB of current byte
++val; // overflow, add 1
if(val & 0x80) // check MSB of (last) seed
val ^= 0x9; // polynome
cb <<= 1;
} while(--q);
val &= 0x7f; // lower 7 bits
}
return ((val<<1) + 1);
}
#endif
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