What is Register Memory? Advantages and Disadvantages of Register Memory

Definition -: Register Memory is the smallest memory of the computer system which is much faster than the rest of the memory. It is not part of the primary memory, rather it is located in the CPU in the form of a register, which stores the least amount of data as compared to the rest of the memory.

It holds instructions of the program currently running by the CPU. Before any instruction is processed by the CPU, it is stored in the register, then the CPU takes those instructions from the register and processes them accordingly.

Data is stored from 32 bits to 64 bits in the register memory. CPU speed depends on the number and size (number of bits) of registers.

We can divide the register into many parts on the basis of usage. Some popular registers come in memory – Accumulator, Data Register, Address Register, Program Counter, I/O Address Register, etc.

Let’s now understand all these types of registers one by one.

Different types of memory registers

Data Register
Program Counter (PC)
Instructor Register
Accumulator Register
Address Register
I/O Address Register
I/O Buffer Register
Flag Register
Index Register
Memory Buffer Register

#1. Data Register

It is a 16-bit register, which is used to store operands to be operated by the processor. It serves to temporarily store data received from the I/O device (input/output device).

#2. Program Counter (PC)

It is a 16 bit special function register in 8085 microprocessor. It is also known as instruction pointer register.

It keeps the memory address of the next instruction of the program being processed by the CPU so that the next instruction can be quickly obtained and executed by the CPU after the completion of the current instruction.

In other words, it keeps the address of the memory location of the next instruction after the microprocessor executes the current instruction.

#3. Instructor Register

It is a 16-bit register. It stores instructions that are received from the main memory.

It is used to hold instruction codes, which are to be executed later. The control unit takes instruction from the instructor register, then decodes and executes it.

#4. Accumulator Register

It is a 16-bit register that serves to store results received by the system from the process. The accumulator register is the part of the ALU, which is responsible for arithmetic and logical operations. This register stores the initial data, intermediate result as well as final result.

For Example – The result obtained by the CPU from the process is kept in the Accumulator Register.

#5. Address Register

It is a 12-bit register that stores the address of the memory location where instructions and data are kept.

#6. I/O Address Register

This register is used to hold the address of the I/O device. Here I/O means input/output device.

#7. I/O Buffer Register

This register is used to exchange data between the I/O module and the CPU.

#8. Flag Register

This register checks for various occurrences conditions in the CPU. This special register is known as flag register. The size of this register is one or two bytes as it only holds flag information.

#9. Index Register

Index register is an integral part of computer CPU which helps in modifying the address of memory operand during the execution of program.

#10. Memory Buffer Register

Memory Buffer Register is also called MBR in short. This register is used to perform data/instruction coming from memory and going into memory.

Why do we need register memory?

For fast handling of instructions, CPU register is highly useful. It is much faster than other computer memory and is located at the top of the computer memory hierarchy.

It can store register, instruction, address, or any other type of small data. Such registers make the operation of the CPU efficient and meaningful.

Advantages of Register Memory

It is the fastest memory block hence executes the instructions faster than the main memory.
With the help of registers, instructions are handled by the CPU in a very simple way.
In today’s digital world, there will hardly be any CPU which does not have registers.

Disadvantages of Register Memory

Register memory is small in size so that a large amount of data cannot be stored in it.
It is quite expensive as compared to other memory.
If the instruction is bigger than the CPU, then the cache or main memory has to be used along with the register for the operation.

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Conclusion

Friends, I hope that after reading this article you will know very well about, what is your Register memory. what are the types of Register memory? And what are the Advantages and Disadvantages of Register Memory?

If you want a complete tutorial on Computer Fundamentals, then see this article Computer Fundamentals Tutorial. Here you will get all the topics of Computer Fundamentals step by step.

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What is Register Memory? Advantages and Disadvantages of Register Memory