Instruction fetch

The instruction cycle (also known as the fetch–decode–execute cycle, or simply the fetch-execute cycle) is the cycle that the central processing unit (CPU) follows from boot-up until the computer has shut down in order to process instructions.

1. How does instruction fetch work?
2. What is instruction fetch and execution?
3. What is the purpose of fetch instruction?
4. Which registers are used during instruction fetch?

How does instruction fetch work?

The instruction is decoded, while the address of the data to be acted upon is placed in the MAR. The instruction turns out to be ADD, which adds two pieces of data together. The new data is fetched from the address and eventually ends up in the accumulator, along with the results of the previous cycle.

What is instruction fetch and execution?

The fetch execute cycle is the basic operation (instruction) cycle of a computer (also known as the fetch decode execute cycle). During the fetch execute cycle, the computer retrieves a program instruction from its memory. It then establishes and carries out the actions that are required for that instruction.

What is the purpose of fetch instruction?

The basic operation of a computer is called the 'fetch-execute' cycle. The CPU is designed to understand a set of instructions - the instruction set. It fetches the instructions from the main memory and executes them. This is done repeatedly from when the computer is booted up to when it is shut down.

Which registers are used during instruction fetch?

Registers/circuits involved

Memory Buffer Register (MBR) - a two-way register that holds data fetched from memory (and ready for the CPU to process) or data waiting to be stored in memory. Current Instruction register (CIR) - a temporary holding ground for the instruction that has just been fetched from memory.