nuclear@0: #!/usr/bin/python
nuclear@0: # mk_adf.py <bootblock> <payload> <output_adf>
nuclear@0: #
nuclear@0: # Stuff a given bootblock and payload into an output ADF image.
nuclear@0: # 
nuclear@0: # Written & released by Keir Fraser <keir.xen@gmail.com>
nuclear@0: # 
nuclear@0: # This is free and unencumbered software released into the public domain.
nuclear@0: # See the file COPYING for more details, or visit <http://unlicense.org>.
nuclear@0: 
nuclear@0: import struct, sys
nuclear@0: 
nuclear@0: # Amiga bootblock checksum
nuclear@0: def checksum(bb, sum=0):
nuclear@0:     while len(bb):
nuclear@0:         x, bb = struct.unpack(">L",bb[:4]), bb[4:]
nuclear@0:         sum += x[0]
nuclear@0:         if sum >= (1<<32):
nuclear@0:             sum -= (1<<32)-1
nuclear@0:     return sum
nuclear@0: 
nuclear@0: def main(argv):
nuclear@0:     bb_f = open(argv[1], "rb")
nuclear@0:     pl_f = open(argv[2], "rb")
nuclear@0:     out_f = open(argv[3], "wb")
nuclear@0:     bb_dat = bb_f.read()
nuclear@0:     pl_dat = pl_f.read()
nuclear@0: 
nuclear@0:     # Construct bootblock header. We will splice in the checksum later.
nuclear@0:     header = struct.pack(">ccccLLLL",
nuclear@0:                          'D', 'O', 'S', '\0',         # Bootblock signature
nuclear@0:                          0,                           # Checksum (placeholder)
nuclear@0:                          880,                         # Root block
nuclear@0:                          0x60060000,                  # BRA.B +6
nuclear@0:                          (len(pl_dat) + 511) & ~511)  # Payload length, padded
nuclear@0:                          
nuclear@0:     
nuclear@0:     # Compute checksum over header, bootblock, and first 512 bytes of payload.
nuclear@0:     sum = checksum(pl_dat[:512], checksum(bb_dat, checksum(header)))
nuclear@0:     sum ^= 0xFFFFFFFF
nuclear@0:     # Splice the computed checksum into the header
nuclear@0:     header = header[:4] + struct.pack(">L", sum) + header[8:]
nuclear@0:     # Write out the header and bootblock code
nuclear@0:     out_f.write(header)
nuclear@0:     out_f.write(bb_dat)
nuclear@0:     # Pad bootblock to 512 bytes
nuclear@0:     for x in xrange((512-len(bb_dat)-len(header))/4):
nuclear@0:         out_f.write(struct.pack(">L", 0))
nuclear@0:     # Write the payload from sector 1 onwards
nuclear@0:     out_f.write(pl_dat)
nuclear@0:     # Pad the ADF image to 880kB
nuclear@0:     for x in xrange((901120-len(pl_dat)-512)/4):
nuclear@0:         out_f.write(struct.pack(">L", 0))
nuclear@0:         
nuclear@0: if __name__ == "__main__":
nuclear@0:     main(sys.argv)