insn

Insn is short for instruction, a fundamental unit of execution in a computer’s central processing unit. An instruction represents a single operation that the processor can perform, such as arithmetic, data movement, memory access, or control flow. In most architectures, an insn is encoded in machine code according to the instruction set architecture (ISA).

In software development and computer engineering, insns appear in various forms. An assembler translates human-readable mnemonics into machine insns, producing binary code that the CPU can execute. A disassembler converts binary instructions back into symbolic insns for analysis or debugging. Debuggers and profilers often display program execution as a sequence of insns, sometimes with their addresses, operands, and side effects.

In compiler design and hardware modeling, insn also denotes a single instruction within intermediate representations or backend data structures. Back-end components perform tasks such as instruction selection, scheduling, and register allocation on a sequence of insns. The specific meaning and representation of an insn depend on the context and the ISA being targeted.

Note that insn is not a universal, formal term with a single fixed definition across all domains. Its precise meaning varies by context, but it generally refers to a single, atomic operation that a processor can execute. When used in documentation or code, insn is typically accompanied by details such as the opcode, operands, addressing mode, and semantic effects.

See also: instruction set architecture, assembly language, disassembly, compiler back end, debugging and profiling tools.