Load and store instructions begin execution in stage three, and integer instructions in stage four. Integer execution was delayed until stage four so that integer instructions which use the result of a load as an operand may be issued in the cycle after the load.
The initial stages of instruction execution are defined by loading and storing instructions (stage three) and then integer instructions (stage four). To ensure efficient operation, integer instructions requiring a load's output as an operand are processed after the load instruction has been executed in the subsequent cycle.