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2. The Registers used

A number of registers (memory locations) inside the CPU are involved with the cycle. These are shown below

registers in fetch cycle

The registers are:-

  • The MBR (Memory Buffer Register)
  • The MAR (Memory Address Register)
  • Program Counter
  • Accumulator
  • Instruction Register

Over the next few pages we will look at how these registers are used in each stage of the cycle.


Challenge see if you can find out one extra fact on this topic that we haven't already told you Click on this link: Fetch Decode Cycle