3.1.4 Instruction Set

Question 1

What is an instruction set?

Answer 1

A list of all the machine code commands that a CPU can process.

Question 2

In what form are instruction set commands written?

Answer 2

Machine code.

Question 3

How does the CPU process instructions from the instruction set?

Answer 3

Using the Fetch–Decode–Execute cycle.

Question 4

What does the Current Instruction Register (CIR) store?

Answer 4

CIR stores the opcode and operand of the current instruction.

Question 5

Which two CPU components are instructed by operations?

Answer 5

The Arithmetic Logic Unit (ALU) and the Control Unit (CU).

Question 6

What are the two parts of an instruction?

Answer 6

Opcode and operand.

Question 7

What is an opcode?

Answer 7

It tells the CPU what operation to perform.

Question 8

What is an operand?

Answer 8

The data to be acted on or the memory/register location.

Question 9

Give examples of instruction set operations

Answer 9

ADD, JMP, LDA.

Question 10

What is X86?

Answer 10

A common CPU instruction set standard used in modern computers.

Question 11

Why do X86-based computers have similar instruction sets?

Answer 11

Because they follow the same CPU standard despite different hardware designs.

Question 12

What is the difference between program code and instruction set?

Answer 12

• Program code must be compiled or interpreted into machine code, while the instruction set is machine code understood directly by the CPU.

Question 13

Why must instruction sets not be confused with program code?

Answer 13

Because program code is converted into instruction set commands before execution.