Cambridge O Level Computer Science · Syllabus 2210 · Hardware
Instruction Set
What is Instruction Set?
An instruction set is the complete list of machine-code operations a particular processor is built to carry out, defining every command that processor can decode and execute and so making machine code specific to that processor's design.
This definition is part of the Hardware chapter in Cambridge O Level Computer Science.
Instruction Set in context
An instruction set is the complete list of all the commands that a particular CPU can process, and those commands are machine code. It is a property of the processor design, not of any one program: every program that runs on that CPU must, in the end, be expressed using instructions from its set.
Common mistakes with Instruction Set
- 13. “An instruction set is one program.” Why wrong It confuses the vocabulary with a sentence written in it. Every program on a CPU draws from the same set. Correct model An instruction set is the complete list of all the commands a CPU can process, written in machine code. It belongs to the processor design, not to any one program. Exam-safe “An instruction set is a list of all the commands that can be processed by a CPU, and the commands are machine code.” Check: two programs run on the same CPU. Do they use the same instruction set?Yes. Both must be built from the instructions that particular CPU can process, even though the two programs do completely different things.
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