S-record checksum calculator

srec-checksum.py

#!/usr/bin/env python

# usage: $ ./srec-checksum.py <s-record without checksum>

import sys

cad = sys.argv[1]
i = 2
checksum = 0
while i<len(cad):
    checksum = checksum + ord(cad[i:i+2].decode("hex"))
    i+=2

if (cad[0:2] == "S1"):
    out = "Data record, address 16 bits"
    address = cad[4:8]
elif (cad[0:2] == "S2"): 
    out = "Data record, address 24 bits"
    address = cad[4:10]
elif (cad[0:2] == "S3"):
    out = "Data record, address 32 bits"
    address = cad[4:12]
elif (cad[0:2] == "S9"):
    out = "Termination record, address 16 bits"
    address = cad[4:8]
elif (cad[0:2] == "S8"):
    out = "Termination record, address 24 bits"
    address = cad[4:10]
elif (cad[0:2] == "S9"):
    out = "Termination record, address 32 bits"
    address = cad[4:12]
elif (cad[0:2] == "S0"):
    out = "Header record"
    address = "0000"

print "[*] Record type: %s\taddress=0x%s"%(out, address)
print "[*] Checksum: %s\n[*] S-Record: %s"%(hex(checksum^0xff)[-2:].upper(), cad + hex(checksum^0xff)[-2:].upper())