2 # Fill in checksum/size of an option rom, and pad it to proper length.
4 # Copyright (C) 2009 Kevin O'Connor <kevin@koconnor.net>
6 # This file may be distributed under the terms of the GNU GPLv3 license.
10 from python23compat import as_bytes
12 def alignpos(pos, alignbytes):
14 return (pos + mask) & ~mask
17 if (sys.version_info > (3, 0)):
20 cksum = sum(map(ord, data))
21 return struct.pack('<B', (0x100 - cksum) & 0xff)
28 f = open(inname, 'rb')
33 # Pad to a 512 byte boundary
34 data += as_bytes("\0") * (alignpos(count, 512) - count)
37 # Check if a pci header is present
38 pcidata = ord(data[24:25]) + (ord(data[25:26]) << 8)
40 blocks = struct.pack('<H', int(count/512))
41 data = data[:pcidata + 16] + blocks + data[pcidata + 18:]
43 # Fill in size field; clear checksum field
44 blocks = struct.pack('<B', int(count/512))
45 data = data[:2] + blocks + data[3:6] + as_bytes("\0") + data[7:]
48 data = data[:6] + checksum(data) + data[7:]
51 f = open(outname, 'wb')
55 if __name__ == '__main__':