Instruksjonsflyten

Instruksjonsflyten, or instruction flow, refers to the sequence in which a central processing unit (CPU) executes instructions from a program. When a program is loaded into memory, its instructions are stored in a specific order. The CPU fetches these instructions one by one from memory, decodes them to understand the required operation, and then executes them. This sequential fetching, decoding, and execution constitutes the basic instruction flow.

The program counter (PC) is a crucial register within the CPU that keeps track of the address of the next instruction to be fetched. Typically, after an instruction is executed, the PC is incremented to point to the subsequent instruction in memory. However, this sequential flow can be altered by control flow instructions. Branch instructions, for example, can change the value of the PC to a different memory address, effectively jumping to another part of the program. This allows for conditional execution, loops, and function calls, making programs dynamic and capable of complex logic.

Modern CPUs often employ techniques like pipelining to improve instruction flow efficiency. Pipelining breaks down the instruction execution process into multiple stages (e.g., fetch, decode, execute, write-back) and allows the CPU to work on different stages of multiple instructions concurrently. This overlap significantly speeds up program execution by reducing the time it takes to complete a sequence of instructions, even though each individual instruction might still take a similar amount of time to fully process. Understanding instruction flow is fundamental to comprehending how software interacts with hardware.