Workflow Diagram of Instruction RegisterFlow-diagram-of-Instruction Register
Here is explanation of each component of above diagram:
- Memory: This is the location of instructions and data. Information is fetched and stored by the CPU via its communication with memory.
- Memory Control Unit: It controls the flow of information in between the CPU and memory.
- Address Register: It is the pointer that points to the next machine which is used for fetching instructions.
- Instruction Fetch Unit: It reads the instruction from the memory location addressed.
- Instruction Register (IR): Temporarily holds the fetched instruction. Here, the opcode and operands can be found.
- ALU (Arithmetic Logic Unit): Executes all the arithmetic and logic instructions retrieved from the internal register.
In running the programs, the CPU goes to memory, fetching out the Instructions, storing it in the Instruction register, decoding opcodes and executing the operation using the ALU. The process is iterative, such that it will be repeated for every instruction included in a program. The instruction register plays a vital role in the execution cycle as it makes possible for the CPU to know what operation should take place.
Role of instruction register in CPU
The instruction register is an integral part of the instruction processing cycle of the CPU. The CPU fetches the current instruction from memory and loads it into the instruction register. The instruction register holds the instruction until the processor decodes and executes it. Once the instruction is executed, the instruction register is updated with the next instruction, and the process continues.
Step-by-Step Process
- Fetch Phase: Once a program has been commenced, the CPU receives from the memory into the Instruction Register the following instruction. This step is important as it ensures that the CPU understands what operation it should execute.
- Decode Phase: The CPU fetches an instruction and decodes it, thereby interpreting the command that should be issued. This decoding process is important in the holding of information in the instruction register.
- Execute Phase: This decoded instruction is then executed, with the results sometimes being fed back into the memory or other registers. Example: consider a simple instruction: ADD R1, R2, R3.
- Fetch: CPU obtains the instruction to be executed from memory.
- Decode: It realizes that the instruction is an addition operation.
- Execute: The sum of contents from registers R2 and R3 is added to R1 by the CPU.
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
Contact Us