A level Computer Science Fetch Decode Execute

First Step of the FETCH

• The CPU reads the contents of the Program Counter to find the address of the next instruction to be fetched

• The address in the MAR is then located in RAM

• The contents of the RAM address are moved to the MDR

• The instruction in the MDR is copied to the CIR

What happens in FETCH immediately after the CPU reads the contents of the Program Counter to find the address of the next instruction to be fetched

• The Program Counter is copied to the CIR

• The Program Counter is incremented

• The contents of the data bus is read

• The contents of the MDR is read

CIR Stands for

• Current Instruction RAM

• Current Instruction Register

• CPU Information Register

• Combined Information Register

• Combined Instruction Register

The first step in the DECODE step is

• The contents of the CIR are divided into instruction and data

• The contents of the CIR are copied to the PC.

• The contents of the CIR are copied to the RAM.

• The contents of the CIR are copied to the ALU.

In the EXECUTE stage the result of a calculation is stored in the ..

• ALU

• MDR

• Control Bus

• Accumulator

• Operand

The PC contains

• Operand

• Address

• Operator

• Data

IN the FETCH step the contents of the address identified by the PC are moved to the

• Accumulator

• CIR

• MAR

• PC

Holds the RAM address you want to read to or write from.

• MAR

• CIR

• MDR

• Accumulator

What is the YELLOW REGISTER

• ACC

• MAR

• CIR

• RAM

In the FETCH step what is copied into the CIR

• Contents of Memory

• Contents of MBR

• Contents of C

• Contents of ALU