NOTTER and ANDER in Computers

 All things in all posts will help you visualize about the way that computers work generally. Note that it is not the real structure of modern computers, but the way that modern computers work is nearly the same as in my posts. I am sure that if you understand about the way that computers work in my posts, you will easy to learn about all fields of computer afterward. Thank you !!!

Firstly, we come to the NOTTER. The NOTTER is a component in the CPU of computers. This device has a simple structure that is constructed from eight NOT gates. The input of NOTTER will be one byte that is in a register and the output of NOTTER is also one byte that is in another register. Let’s look at the diagram of NOTTER below:

As you can see on the diagram, each bit of byte in register will be inverted signals, from “0” to “1” or from “1” to “0”, because bits go through NOT gates (inverters). For example, if we have a byte of 10010010, when that byte goes through NOTTER, the byte output will be 01101101.

You may wonder what is the use of this NOTTER? Yeah, this NOTTER will be used in some calculations such as NOT operation in logical calculation or finding opposite numbers,...You will see the way that this NOTTER is used in constructing the CPU of a computer in my next posts.

Now, let’s conduct a familiar work that is abstracting this NOTTER. Look at the diagram below to see:

Next, we come to the ANDER. The ANDER will have two bytes in two registers as inputs and one byte in one register as output. This ANDER is constructed from eight AND gates. Each corresponding bit in each byte of inputs will go in the same AND gate. For example, the first bit of the first register will go in the same AND gate as the first bit of the second register and similar for remaining bits. 

Then, the outputs of AND gates will become bits in one register. This register will be the place that contains output of ANDER. Let’s look at the diagram below for understanding structures of ANDER:

You can see that all is the same as I described. Now, what is the use of the ANDER? In reality, we have many tasks that need this ANDER and one of them is converting lowercase letters to uppercase letters. For example, we have a lowercase letter of “a” that has binary code in ASCII table of “01100001”. Assume that this byte of letter is in a register of R0, then we have another byte of “11011111” in R1. 

We will use ANDER for R0 and R1 above then the result will be stored into R0 again. As you can see, R0 and R1 will be inputs of ANDER, so we use AND gates for every pair of corresponding bits. Now, every bit in the result R0 will be the same as R0 at first, except the third bit (because we have an “0” signal in the third bit of R1).

We will have a result in R0 is “01000001” that is binary for “A” letter in the ASCII table. So, we converted lowercase “a” letter to uppercase “A” letter. Now, we will abstract this ANDER gate for easier use later. Look at the diagram below:

That is about NOTTER and ANDER in constructing the CPU of computers. Thanks for reading and see you later!!!