IGCSE CS Exam Revision

Select all of those which are registers in the CPU.

• Accumulator

• ALU

• Program Counter

• Memory Address Register

• Control Bus Register

Select all options that happen in the fetch part of the fetch-execute cycle.

• PC is incremented

• The Instruction at the MAR address is read from RAM

• The PC value is copied to the MAR

• The instruction in the MAR is decoded

• The value in the MDR is written to the address in the MAR.

Select all options that happen in the execute part of the fetch-execute cycle.

• PC is incremented

• The data at the MAR address is read from RAM

• The ALU performs any calculations required on the ACC

• The instruction in the MAR is decoded by the CU

• The value in the MDR is written to the address in the MAR.

Select all options that happen during decoding of an instruction.

• PC is incremented

• The Instruction at the MAR address is read from RAM

• The PC value is copied to the MAR

• The instruction in the MAR is decoded by the CU

• The value in the MDR is written to the address in the MAR.

What does MAR stand for?

• Main Address Register
• Memory Address Register
• Massive Address Register
• Minimal Age Readable

The idea developed in 1945 by Von Neumann of a computer holding both programs and the data used by the programs in memory is called what?

• Stored Program Concept

• Memory Program System

• Stored Memory Concept

• Stored Memory Program

The small high speed storage areas within the CPU are known as what?

• Registers

• Addresses

• Cache

• Buses

The Program Counter (PC) does what?

• Stores the address of the next instruction in memory

• Stores the address of where the next item will be fetched from

• Stores data fetched from memory, or waiting to be stored in memory

• Stores the result of arithmetic calculations

The Memory Address Register (MAR) does what?

• Stores the address of the next instruction in memory

• Stores the address of where the next item will be fetched from

• Stores data fetched from memory, or waiting to be stored in memory

• Stores the result of arithmetic calculations

The Arithmetic Logic Unit (ALU) does what?

• Carries out numerical calculations and logical decisions

• Calculates the different items of number data stored within the Accumulator and converts them into logical decisions

• Calculates graphic data as they are only found within GPU units.

• Calculates the flow of execution in a program and decodes instructions into small steps to be carried out by the program counter.