from migen import *


class Mem(Module):
    def __init__(self):
        # Initialize the beginning of the memory with integers
        # from 0 to 19.
        self.specials.mem = Memory(16, 2**12, init=list(range(20)))

    def do_simulation(self, selfp):
        # Read the memory. Use the cycle counter as address.
        value = selfp.mem[selfp.simulator.cycle_counter]
        # Print the result. Output is:
        # 0
        # 1
        # 2
        # ...
        print(value)
        # Raising StopSimulation disables the current (and here, only one)
        # simulation function. Simulator stops when all functions are disabled.
        if value == 10:
            raise StopSimulation

if __name__ == "__main__":
    run_simulation(Mem())