splitroms.py

#!/usr/bin/python

# This program accepts as input the files apple1.rom and cassette.rom,
# which should be 256-byte binary files of Apple 1 firmware, and generates
# nibble-wide files suitable for MAME. It also writes to standard output
# the ROM_LOAD_NIB_xxx directives that should be used in the MESS
# src/mess/drivers/apple1.c source file.

# Copyright 2011 Eric Smith <eric@brouhaha.com>
#
# This program is free software; you can redistribute and/or modify it
# under the terms of the GNU General Public License version 3 as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# The text of the license may be found online at:
#     http://www.brouhaha.com/~eric/software/GPLv3
# or:
#     http://www.gnu.org/licenses/gpl-3.0.txt

import hashlib
import zlib

def crc_str (data):
    crc32 = zlib.crc32 (data) & 0xffffffff
    return "%08x" % crc32

def sha1_str (data):
    h = hashlib.new ('sha1')
    h.update (data)
    return h.hexdigest ()

def splitrom (byte_fn, addr, low_fn, high_fn):
    with open (byte_fn, 'rb') as byte_f:
        data = byte_f.read ()
        low = ''
        high = ''
        for i in range (len (data)):
            low += chr (ord (data [i]) & 0x0f)
            high += chr (ord (data [i]) >> 4)
        print '\tROM_LOAD_NIB_HIGH( "%s", 0x%04x, 0x%04x, CRC(%s), SHA1(%s) )' % (high_fn, addr, len (high), crc_str (high), sha1_str (high))
        print '\tROM_LOAD_NIB_LOW( "%s", 0x%04x, 0x%04x, CRC(%s), SHA1(%s) )' % (low_fn, addr, len (low), crc_str (low), sha1_str (low))
        with open (low_fn, 'wb') as low_f:
            low_f.write (low)
        with open (high_fn, 'wb') as high_f:
            high_f.write (high)

splitrom ('apple1.rom',
          0xff00,
          'apple-a1.a1',  # low nibble
          'apple-a2.a2')  # high nibble

splitrom ('cassette.rom',
          0xc100,
          'apple-a4.4',   # low nibble
          'apple-a3.3')   # high nibble