#!/usr/bin/env python

import sys

# map of address pin connections: bus address line -> ROM address line
addr_line_map = {
        0: 11,
        1: 10,
        2: 9,
        3: 8,
        4: 7,
        5: 6,
        6: 5,
        7: 4,
        8: 3,
        9: 2,
        10: 1,
        11: 0,
        12: 14,
        13: 13, # we got one right!
        14: 12,
        }

def scramble_addr(busaddr):
    romaddr = 0
    for bus_bit, rom_bit in addr_line_map.iteritems():
        if busaddr & (1 << bus_bit):
            romaddr |= (1 << rom_bit)
    return romaddr

if __name__ == '__main__':
    # check command line arguments
    if len(sys.argv) != 3:
        print "syntax: %s [inputfile] [outputfile]" % sys.argv[0]
        sys.exit(1)

    # start with an empty ROM (0xFF = unprogrammed byte)
    data_out = [chr(0xFF)] * (2**len(addr_line_map))

    # load data from input file
    data_in = open(sys.argv[1], 'rb').read()
    if len(data_in) > len(data_out):
        print "Error: input file larger than expected (max %d bytes)" % len(data_out)
        sys.exit(1)

    # scramble it
    for addr, value in enumerate(data_in):
        data_out[scramble_addr(addr)] = value

    # write result to output file
    open(sys.argv[2], 'wb').write(''.join(data_out))

; Make sure that panel memory and main memory are distinct...
	POST+4			; set the POST code to four
	STA			; put -1 in location 0 of panel memory
	DCA	@[0]		; ...
	CPD			; and then put 0 in the same location
	DCA	@[0]		;  ... of main memory
	SPD			; back to panel memory
	ISZ	@[0]		; and increment -1
	 JMP   	.		; if it doesn't skip something is wrong