Glossary
Instruction Set Architecture (ISA)
The complete specification of a processor's instructions, registers, and addressing modes that software can rely on.
An Instruction Set Architecture (ISA) is the abstract specification of what instructions a CPU understands, how opcodes are encoded, which registers exist, and what addressing modes are available. It is the contract between hardware and software. Common ISAs encountered in reverse engineering include x86, x86-64 (AMD64), ARM, AArch64, and MIPS. The ISA determines the mnemonics a disassembler emits and shapes how you read assembly. Switching between ISAs requires relearning instruction syntax, register names, and calling conventions.