assembler.py

import sys

"""
These are some look up tables used in translating the words into
hex. They are hash tables that correspond from one string to another
"""
commands = {
	'NOP'    : '0',
	'MOVIR0' : '1',
	'MOVIR1' : '2',
	'DISPLAY': '3',
	'MOVAR0' : '4',
	'MOVAR1' : '5',
	'ADD'    : '6',
	'AND'    : '7',
	'OR'     : '8',
	'XOR'    : '9'
}


def main(argv):
	
	# make sure to provide a filename
	if len(argv) < 2:
		print("Error: Please specify an input filename")
		return

	# open the input and output files
	infile = open(argv[1], 'r')
	outfile = open('a.out', 'w')

	# do one line at a time
	line = infile.readline()
	while line != '':
		# split into the command and the argument
		parts = line.split()

		# get the hex for the command given
		outfile.write(commands[parts[0]])

		# add the arg or a 0
		if len(parts) > 1:
			# this fancy dancy stuff converts the string into binary
			# http://stackoverflow.com/a/5092707/3861623
			outfile.write(hex(int(parts[1], 2))[2])
		else:
			outfile.write('0')

		outfile.write('\n')

		# continue to the next line
		line = infile.readline()


# This is here to ensure main is only called when
#   this file is run, not just loaded
if __name__ == "__main__":
    main(sys.argv)