Utasításkészlete

Utasításkészlete, commonly referred to as an instruction set architecture (ISA), is the part of the computer architecture that defines the interface between hardware and software. It dictates the commands a central processing unit (CPU) can understand and execute. Think of it as the fundamental language that a processor "speaks."

An ISA specifies the types of instructions available, the data types that can be manipulated, the registers available for storing data, the addressing modes for accessing memory, and the format of instructions. Different processors, even those from the same manufacturer, can have different instruction sets. For example, x86 is a widely used ISA for personal computers, while ARM is prevalent in mobile devices.

The ISA is crucial because it determines the capabilities of a processor and how software must be written to interact with it. Compilers translate high-level programming languages into machine code, which consists of instructions specific to the target processor's ISA. When a program is executed, the CPU fetches these instructions and performs the specified operations.

Designing an ISA involves trade-offs between complexity and performance. A simpler ISA (like RISC - Reduced Instruction Set Computing) aims for fewer, more efficient instructions, while a more complex ISA (like CISC - Complex Instruction Set Computing) can perform more operations with a single instruction, potentially simplifying software development but requiring more complex hardware. The choice of ISA significantly impacts the overall design and capabilities of a computing system.