Converts a VGM file to BASIC POKEs

dumpvgm.py

#!/usr/bin/python3

import argparse

# parse arguments
parser = argparse.ArgumentParser(formatter_class=argparse.RawTextHelpFormatter,
    description='Converts a VGM file to BASIC POKEs.')
parser.add_argument('input', help='the input file name')
args = parser.parse_args()

# calculate absolute data offset
data = open(args.input, "rb").read()
i = data[0x34]
i = i + (data[0x35] << 8)
i = i + (data[0x36] << 16)
i = i + (data[0x37] << 24)
i = i + 0x34
print("absolute data offset: %04x" % i)

# read next byte
def next():
    global i
    d = data[i]
    i = i + 1
    return d

# print wait info
def wait(n):
    print("wait %i frames" % n)

# start convert
line = 10
while i < len(data):
    d = next()
    if d == 0x54:
        reg = next()
        d = next()
        print("%i POKE $9FE0, $%02X : POKE $9FE1, $%02X" % (line, reg, d))
        line = line + 10
    elif d == 0x61:
        n = next()
        n = n + (next() << 8)
        wait(n)
    elif d == 0x62:
        wait(735)
    elif d == 0x63:
        wait(882)
    elif d == 0x66:
        break
    elif d == 0xc0:
        # Sega PCM
        i = i + 3
    elif d >= 0x70 and d <= 0x7f:
        wait(d & 0xf)
    else:
        print("unknown command: %02x\n" % d);
        break