Instruction Set by Instruction Register
An instruction set is a set of all possible instructions which can be run by the CPU. At the same time, the IR performs tasks to read and decode them into machine code.
Here’s a breakdown of how the instruction set is typically processed using the Instruction Register:
- Fetch: The CPU fetches the next instruction during the fetch stage of the instruction cycle from memory. PC keeps the address of the upcoming fetchable instruction. During its operation, the computer fetches an instruction from a certain memory address that is then loaded into the Instruction Register for processing.
- Decode: When the instruction is fetched to the CPU, it has to know what operation it should do. During decoding, the binary code contained in the Instruction Register is interpreted for its operation, operand, as well as other necessary information.
- Execute: The CPU performs the operation specified in the instruction after decoding. It can encompass actions such as changing data, simple mathematics functions or branching processes.
- Write Back (optional): Sometimes, the outcome is used to update a register or the memory cell. This step is not compulsory because it depends on the characteristics of instruction.
The instruction register provides an intermediate place where the currently executing instruction will temporarily reside while it is being fetched and decoded. CPU is enabled to execute just one instruction in this mode so as to ensure accuracy of the operation.
The size/format of instructions stored in the Instruction Register varies from one computer to another, which is determined by the architecture of the CPU and its instruction set. However, some CPUs apply fixed-length (where every instruction is fixed number of bits) or variable length instructions. Decoding is a process in which the opcode (operation code) together with additional operands/addressing modes, as stipulated by instruction format, are interpreted.
Instruction Register
Do you ever wonder how your computer makes sense of your commands and responds accordingly? What is there to say? It is no magic, but a thing called the Instruction Register. “Fancier” is perhaps one way to say “It’s akin to the conductor at an orchestra where every note (instruction) should be perfect.”
Today in this article, we are going to explore about mystery that exists in the Instruction Register. Whether you are techie or just anyone who is interested in knowing what it actually does inside one’s computer; here comes our trip to unraveling these mysteries. Therefore, fasten you seat belts, come with me and allow us take a close look at the Instruction Register but in an easy-to-understand version.
- Central Processing Unit (CPU): These include a central processing unit (CPU) that is responsible for interpreting and following instructions from memory stored within various parts of a computing system. This unit has several parts which include the Instruction Register, ALU, and the Control Unit.
- Memory: Data and instructions are stored in memory in a computer system. Memory communicates with the CPU in the sense that it fetches, stores as well as processes the data.
Table of Content
- What is an Instruction Register?
- What is Program Counter?
- Difference Between Program Counter (PC) and Instruction Register (IR)
- How do Instruction Registers Work?
- Workflow Diagram of Instruction Register
- Types of Instruction Register
- Features of Instruction Register
- Importance of Instruction Register
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