Organisation

Question 1

ARM has a three-address format:

Answer 1

Rd — destination register

Rn — source register

Rm — source register

e.g. ADD R0,R1,R2.

Question 3

Rn is used directly but where is Rm Passed through?

Answer 3

Rm is passed through the barrel shifter; a functional unit which can rotate and shift values. The result of this is called Operand2.

Question 4

How is Register Bank, Barrel shifter, ALU and CPSR connected?

Question 5

The two operands are processed by the ALU and the result written to which location of the register bank?

Answer 5

The destination register

Question 6

Although it’s a register, we show the CPSR separately on the diagram to indicate that it may be used in both the barrel shifter and the ___ stages.

Answer 6

Although it’s a register, we show the CPSR separately on the diagram to indicate that it may be used in both the barrel shifter and the ALU stages.