instrukciókészlet

The instruction set, often abbreviated as ISA (Instruction Set Architecture), is the fundamental interface between a computer's hardware and its software. It defines the set of primitive commands that a central processing unit (CPU) can understand and execute. These commands, known as instructions, dictate operations such as arithmetic calculations, data movement, logical operations, and control flow.

Each instruction in the ISA is typically represented by a specific binary code, known as an opcode, along with associated operands that specify the data or memory locations to be manipulated. The ISA dictates not only the instructions themselves but also the format of these instructions, the addressing modes available for accessing data, and the registers that the CPU can use.

Different CPU architectures have different instruction sets. For example, x86, commonly found in personal computers, has a complex instruction set (CISC), while ARM, prevalent in mobile devices, uses a reduced instruction set (RISC). The choice of ISA significantly impacts a processor's performance, power consumption, and the complexity of the software required to program it. Compilers and assemblers translate higher-level programming languages into machine code that conforms to a specific ISA, allowing software to run on compatible hardware.