import machine
from machine import Pin

#ENTRADA
B_1_IN = Pin(18, Pin.IN, Pin.PULL_UP)
B_2_IN  = Pin(2, Pin.IN, Pin.PULL_UP)
A_1_IN  = Pin(19, Pin.IN, Pin.PULL_UP)
A_2_IN  = Pin(4, Pin.IN, Pin.PULL_UP)


#SALIDA
S_1_OUT = Pin(14, Pin.OUT)
S_2_OUT = Pin(12, Pin.OUT)
C_OUT = Pin(13, Pin.OUT)

while True:
    B_1 = B_1_IN.value()
    B_2 = B_2_IN.value()
    A_1 = A_1_IN.value()
    A_2 = A_2_IN.value()

    #SUMA:
    #        C1
    #        A1 B1
    #      + A2 B2
    #       -------
    #    C2 |S2 S1

    #HALF-ADDLER
    S_1 = (not B_1 and B_2) or (B_1 and not B_2)
    C_1 = (B_1 and B_2)

    #FULL-ADDLER
    Xor = (not A_1 and A_2) or (A_1 and not A_2)
    S_2 = (not C_1 and Xor) or (C_1 and not Xor)

    C_2 = (A_1 and A_2) or (A_1 and C_1) or (A_2 and C_1)

    S_1_OUT.value(S_1)
    S_2_OUT.value(S_2)
    C_OUT.value(C_2)