The Instruction Cycle
The instruction cycle for a computer
Fetch: address contained in PC accessed / loaded into MAR, PC incremented. Memory read / loaded into MDR. MDR contents loaded into IR.
Decode: IR contents decoded
Evaluate Address: contents of base register / PC offset added, supplied via MARMUX to MAR. Sources selected.
Operand Fetch: data at that address loaded into MDR
Execute: If operations require execution, here be where that done did.
Store results: MDR loaded into DR or memory location specified by operation.