P89lpc9xx CRC Calculation

Used to verify the data in the sector. Read sector CRC is correct only after many effortsAlgorithm:

 

Unsigned long distrined (unsigned char data)
{
Unsigned long tap,;
Unsigned char data2;
Tap = 0;

Data2 = data <7;
A = data2> 7;
A = A <0;
Tap = tap |;

Data2 = (Data <(8-1-1 ));
A = data2> 7;
A = A <3;
Tap = tap |;

Data2 = (Data <(8-2-1 ));
A = data2> 7;
A = A <5;
Tap = tap |;

Data2 = (Data <(8-3-1 ));
A = data2> 7;
A = A <8;
Tap = tap |;

Data2 = (Data <(8-4-1 ));
A = data2> 7;
A = A <10;
Tap = tap |;

Data2 = (Data <(8-5-1 ));
A = data2> 7;
A = A <13;
Tap = tap |;

Data2 = (Data <(8-6-1 ));
A = data2> 7;
A = A <16;
Tap = tap |;

Data2 = (Data <(8-7-1 ));
A = data2> 7;
A = A <18;
Tap = tap |;

Return tap;
}

Unsigned long CRC32 (unsigned char * buffer, int Len)
{
Unsigned long CRC, tap, crc_flag;
Int I;
Unsigned char B;

CRC = 0;
Tap = 0;
Crc_flag = 0;

For (I = 0; I <Len; I ++ ){
B = buffer [I];

Crc_flag = CRC> 31;
CRC = CRC <1;

Tap = distribute (B );

CRC = CRC ^ tap;

If (crc_flag = 0 ){
}
Else {
CRC = CRC ^ 0x00400007;
}
}

Return CRC;
}