Now we go another step, and just forget about gates, since now we've a Block, an ADDER. Our computer is made through the use of different combinations of logic blocks. As well as the adder we possibly may have a multiplier (a series of adders) and other parts.
Our ADDER stop requires one bit (0 or 1) from each number to be added, as well as the Carry bit (0 or 1) and generates an output of 0 or 1, and a of 0 or 1. A table of the input A, B and Carry, and output O and Carry, seems like this:-
With no Carry in:
A T c O C
0 0 0 0 0
1 0 0 1 0
0 1 0 1 0
1 1 0 0 1
With Carry in:
A B c O C
0 0 1 1 0
1 0 1 0 1
0 1 1 0 1
1 1 1 1 1
That is referred to as a Table, it shows output state for any given input state.
Let's put 2+3 decimal. That is 010 plus 011 binary. ADDER blocks will be needed 3 by us for decimal bit values of 1, 2 and 4)
The very first ADDER requires the Least Significant Bit (decimal bit price 1) from each number. Input A will be 0, input B will be 1 without any hold - 0.
From the reality table this gives a result of 1 and a of 0 (3rd row). BIT 1 RESULT = 1
At the same time the following ADDER (decimal bit price 2) has inputs of 1, 1 and a of 0, giving a result of 0 with a bit of 1 (4th row). Power System Feedback Test contains further concerning why to recognize it. BIT 2 RESULT = 0
Another ADDER (decimal bit price 4) has inputs of 0, 0 and a of 1, providing an output of 1 without any carry - 0 (5th line). TOUCH 4 RESULT = 1.
So we have bits 4,2,1 as 101 or 4+1=5.
It may seem like a laborious method to do it, but our computer can have 64 adders or even more, adding simultaneously two good sized quantities billions of times an additional. That is where the computer results.
The next occasion we shall reach what sort of computer works more complcated procedures, and it is simple!.
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