55 lines
1.3 KiB
Python
Executable File
55 lines
1.3 KiB
Python
Executable File
#!/usr/bin/env python
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# Fill in checksum/size of an option rom, and pad it to proper length.
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#
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# Copyright (C) 2009 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import sys, struct
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def alignpos(pos, alignbytes):
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mask = alignbytes - 1
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return (pos + mask) & ~mask
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def checksum(data):
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if (sys.version_info > (3, 0)):
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cksum = sum(data)
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else:
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cksum = sum(map(ord, data))
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return struct.pack('<B', (0x100 - cksum) & 0xff)
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def main():
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inname = sys.argv[1]
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outname = sys.argv[2]
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# Read data in
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f = open(inname, 'rb')
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data = f.read()
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f.close()
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count = len(data)
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# Pad to a 512 byte boundary
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data += b"\0" * (alignpos(count, 512) - count)
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count = len(data)
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# Check if a pci header is present
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pcidata = ord(data[24:25]) + (ord(data[25:26]) << 8)
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if pcidata != 0:
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blocks = struct.pack('<H', int(count/512))
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data = data[:pcidata + 16] + blocks + data[pcidata + 18:]
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# Fill in size field; clear checksum field
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blocks = struct.pack('<B', int(count/512))
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data = data[:2] + blocks + data[3:6] + b"\0" + data[7:]
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# Checksum rom
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data = data[:6] + checksum(data) + data[7:]
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# Write new rom
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f = open(outname, 'wb')
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f.write(data)
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f.close()
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if __name__ == '__main__':
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main()
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