Back to Wb 2020 10 26

Booklet 1

  1. A processor contains a number of special registers.
    Name and describe three buses used to convey information between the special registers.

    • What? When did we cover this? Data/Address/Control buses aren't used to convey information between registers...

  2. A processor contains a number of special registers.
    Explain the need for the following registers.

    1. Program Counter
      • The PC is needed to store the address of the next instruction to be read from memory in the fetch-decode-execute cycle
    2. Memory Address Register
      • The MAR is needed to store the address of the next read from memory, whether it is instruction or data
    3. Memory Data Register
      • The MDR is needed to store the last word (instruction or data) fetched from memory, for use by the processor

  3. Processors use special registers.

    1. Explain why special registers are needed in addition to primary memory.
      • Primary memory is too slow to be read from constantly, so registers are used instead in order to run the program faster