mirror of
https://github.com/eried/portapack-mayhem.git
synced 2024-12-20 21:24:22 -05:00
58 lines
1.4 KiB
Python
58 lines
1.4 KiB
Python
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#!/usr/bin/env python3
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#
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# Copyright (C) 2024 Mark Thompson
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#
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# This file is part of PortaPack.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2, or (at your option)
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# any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; see the file COPYING. If not, write to
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# the Free Software Foundation, Inc., 51 Franklin Street,
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# Boston, MA 02110-1301, USA.
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#
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import sys
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import struct
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usage_message = """
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PortaPack ROM image checksum checker
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Usage: <command> <input-file>
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"""
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def read_image(path):
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f = open(path, 'rb')
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data = f.read()
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f.close()
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return data
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def write_image(data, path):
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f = open(path, 'wb')
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f.write(data)
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f.close()
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if len(sys.argv) != 2:
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print(usage_message)
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sys.exit(-1)
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image = read_image(sys.argv[1])
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image = bytearray(image)
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# simple "add up the words" checksum:
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checksum = 0
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for i in range(0, len(image), 4):
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checksum += (image[i] + (image[i + 1] << 8) + (image[i + 2] << 16) + (image[i + 3] << 24))
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checksum &= 0xFFFFFFFF
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print ("Simple checksum =", checksum)
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