加法器

課本 P29

structural
output carry_out, sum;
input a, b, carry_in;
and I1 (a1, b, a);
xor I2 (x1, b, a);
and I3 (a2, x1, carry_in);
xor I4 (sum, x1, carry_in);
or I5 (carry_out, a1, a2);

布林
input
I1 = a&b
I2 = a^b
I3 = (a^b)&carry_in
output
sum = I4 = (a^b)^carry_in
carry_out = I5 = (a&b)+[(a^b)&carry_in]

判斷正確與否

波形圖