Software → Computer Architecture
Instruction Set Architecture
The contract between software and hardware defining instructions, registers, and execution behavior.
Motivation
Instruction Set Architecture solves the problem of defining the contract between software instructions and hardware execution.
Where it fits
ISA belongs to computer architecture and programming languages.
Mental model
An ISA describes instructions, registers, memory model, and behavior visible to machine code.
Common mistakes
- Confusing ISA with a specific CPU implementation.
- Assuming all CPUs with the same ISA have identical performance.
Related concepts
ISA connects to CPU, assembly language, machine code, compiler, and register.