select_generator.py

# LED Suit FPGA Implementation - Multi-output addressable LED driver HDL
# implementation for Kevin's LED suit controller.
# Copyright (C) 2019-2020 Kevin Balke
#
# This file is part of LED Suit FPGA Implementation.
#
# LED Suit FPGA Implementation is free software: you can redistribute it and/or
# modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# LED Suit FPGA Implementation 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.
#
# You should have received a copy of the GNU General Public License
# along with LED Suit FPGA Implementation.  If not, see
# <http://www.gnu.org/licenses/>.

import os, sys

width = int(sys.argv[1])
select_wire = sys.argv[2]
input_wire = sys.argv[3]
output_wire = sys.argv[4]

def ternary(cond, lop, rop):
    return "((%s) ? (%s) : (%s))" % (cond, lop, rop)

def compare(lop, rop):
    return "((%s) == (%s))" % (lop, rop)

def wrap_value(value, width):
    return "%d'%s" % (width, bin(value)[1:])

def select(vector, index):
    return "%s[%s]" % (vector, index)

def generate_selector(width, selector, input_vector, output):
    selector_options = zip([wrap_value(1 << _, width) for _ in range(0, width)], range(0, width))
    return generate_selector_helper(selector_options, selector, input_vector, output)

def generate_selector_helper(selector_options, selector, input_vector, output):
    mask, index = selector_options[0]
    if (len(selector_options) == 1):
        return select(input_vector, index)

    return ternary(compare(mask, selector), ("%s[%s]" % (input_vector, index)),generate_selector_helper(selector_options[1:], selector, input_vector, output))

#print generate_selector(5, "select", "arb_input", "arb_output")
print generate_selector(width, select_wire, input_wire, output_wire)