Utasításlekérdezés

Utasításlekérdezés, often translated as instruction fetching, is a fundamental process in computer architecture. It refers to the retrieval of the next instruction from memory that the central processing unit (CPU) will execute. This is a critical step in the instruction cycle, which is the sequence of operations a CPU performs to execute a program.

The process typically begins with the program counter (PC), a special register within the CPU that holds the memory address of the next instruction. The CPU uses this address to access the memory unit, where the instruction is stored. Once the address is provided to the memory system, the instruction located at that address is retrieved and sent back to the CPU.

After the instruction is fetched, it is usually placed in an instruction register (IR) within the CPU. This fetched instruction is then decoded to determine what operation needs to be performed and what data, if any, is required. This decoding step is crucial as it tells the CPU whether to perform an arithmetic operation, a data transfer, a control flow change, or some other function. Following decoding, the instruction is executed, and the program counter is updated to point to the next instruction, perpetuating the cycle. The efficiency of the instruction fetching mechanism significantly impacts the overall performance of a computer system.