[NEW FEATURE] CRC_IBM

[Salem-Tho]

A CRC calculation on Luos can be change to correspond to standard CRC-16 ANSI / IBM

Actual Luos CRC

• Width = 16 bits
• Truncated polynomial = 0x0007
• Initial value = 0xFFFF
• Input data is NOT reflected
• Output CRC is NOT reflected
• No XOR is performed on the output CRC

CRC-16 ANSI / IBM

• Width = 16 bits
• Truncated polynomial = 0x8005
• Initial value = 0x0000
• Input data is reflected
• Output CRC is reflected
• No XOR is performed on the output CRC

code example:

`uint16_t crc16_ibm(char* data, unsigned int data_len)
{
uint16_t crc = 0;

if (data_len == 0)
    return 0;

for (unsigned int i = 0; i < data_len; ++i) {
    uint16_t dbyte = bit_reflect(data[i], 8);
    crc ^= dbyte << 8;
    
    for (unsigned char j = 0; j < 8; ++j) {
        uint16_t mix = crc & 0x8000;
        crc = (crc << 1);
        if (mix)
            crc = crc ^ 0x8005;
    }
}

return bit_reflect(crc, 16);

}`