Instruction Register

What Does Instruction Register Mean?

An instruction register holds a machine instruction that is currently being executed. In general, a register sits at the top of the memory hierarchy. A variety of registers serve different functions in a central processing unit (CPU) – the function of the instruction register is to hold that currently queued instruction for use.


Techopedia Explains Instruction Register

In a typical CPU, in addition to an accumulator, there are registers such as an address register, a data register and an index register, along with the instruction register. The CPU performs fetch, decode and execute operations on memory units according to its use of the registers. All of this serves the purpose of the memory processing that is at the heart of the CPU’s raison d’etre, which is why some experts call registers “the most important part of the CPU.” In a sense, the instruction register is particularly important in that it holds the “active” memory value that is being worked on at a given time.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…