Q- Implement the 4-bit ADDER and SUBTRACTOR in a single circuit where we select one of the two using a select pin SEL. Ans: The following circuit would work as required: In this circuit we use property of XOR gate by which XOR gate acts as a inverter when we have one input as 1. When sel = […]
Tag: subtraction
Question: Implement Subtractor using Adder
We can also do subtraction using adders. As we have already studied that we can do subtraction by 2’s compliment method in which we add 2’s compliment of subtrahend to minuend and 2’s compliment can be found by inverting all bits of subtrahend and then adding one. So we have to do as F= A […]
Serial and Parallel Subtractors
Similar to the adder case we can have serial and parallel subtractors as shown below: Serial subtractor: In this circuit, we have Input number coming bit by bit and output comes bit by bit and the final borrow at the end: Parallel Subtractor: All inputs are feed simultaneously. Borrow-propagate subtractor: Similar to the case of adder we […]
Subtraction using (r-1)’s compliment
(r – 1) ’s compliment: (M – N) r This is similar to r’s compliment. There is a difference while dealing with the final carry we get If we have both M & N positives, then The Procedure for doing subtraction using (r – 1) ’s compliment is as follow: Take (r – 1) ’s compliment […]
Subtraction using compliments
Subtraction method mentioned earlier looks good when we do it on paper and pencil but to implement a subtraction method on a digital platform then subtraction using compliments is better and efficient. r’s compliment: If we are given numbers M & N with base r, then we can to have to find M – N […]
SUBTRACTION (without using compliment method)
Decimal system: Let’s now analyze the subtraction of decimal systems. For subtraction we first subtract the least significant digit of subtrahend from that of minuend and if least significant digit of subtrahend is greater than that of minuend then we take borrow from the next digit of minuend and add 10 (base) to the previous digit […]