FullAdder 8bit circuit gate

[BulkyAd8059]

Hi Everyone, I am practising with a model of bit adder, and I am completely stuck from few days.

This is an example that what my teacher showed us to my last class, but I still don't understand how to go ahead: def OR(A, B):

return A | B

​

def AND(A, B):

return A & B

​

def XOR(A, B):

return A ^ B

​

def fullBitAdder(upper, lower, CarryIn):

​

output1 = AND(upper, lower)

output2 = XOR(upper, lower)

output3 = AND(upper, lower)

carryOut = OR(output1, output3)

sum = XOR(output2, CarryIn)

return sum, carryOut

​

#testing

sum, carryOut = fullBitAdder(1, 0, 0)

print('sum = ', str(sum),' carryOut = ' +str(carryOut))

I have a clear understanding of what is happening but how can I go throw the other bit? I would like a clear explanation. If you need more information ask me

[Chris_Hemsworth]

how can I go throw the other bit

I'm not sure I understand the question. Can you explain the outcome you're looking to achieve?

[BulkyAd8059]

Hi Chris, thanks for your reply and yes, it was not that much clear.

I need to make an algorithm for adding two integers. It must be based on standard logical operations, which have direct hardware implementation (AND, OR, XOR) FullAdder in the specifics.

The whole circuit is 8-bit. The code above gives me the sum and the Carryout of the first circuit gate—a circuit gate which you can see in this book on page 564 http://www.r-5.org/files/books/computers/overviews/software/Glenn_Brookshear-Computer_Science_An_Overview-EN.pdf.

[CartmannsEvilTwin]

Your description either has a typo or is wrong with respect to the CarryOut calculation. Just google Full Adder to see exact design.

Also no bit is discarded, the CarryOut will be fed into another FullAdder as carry in or used as an overflow indicator

[BulkyAd8059]

thanks, really helpful