The minimum average latency $$(MAL)$$ is ________.
MUL | R5, R0, R1 |
---|---|
DIV | R6, R2, R3 |
ADD | R7, R5, R6 |
SUB | R8, R7, R4 |
In the above sequence, $$R0$$ to $$R8$$ are general purpose registers. In the instructions shown, the first register stores the result of the operation performed on the second and the third registers. This sequence of instructions is to be executed in a pipelined instruction processor with the following $$4$$ stages: $$(1)$$ Instruction Fetch and Decode $$(IF), (2)$$ Operand Fetch $$(OF), (3)$$ Perform Operation $$(PO)$$ and $$(4)$$ Write back the result $$(WB).$$ The $$IF,$$ $$OF$$ and $$WB$$ stages take $$1$$ clock cycle each for any instruction. The $$PO$$ stage takes $$1$$ clock cycle for $$ADD$$ or $$SUB$$ instruction, $$3$$ clock cycles for $$MUL$$ instruction and $$5$$ clock cycles for $$DIV$$ instruction. The pipelined processor uses operand forwarding from the $$PO$$ stage to the $$OF$$ stage. The number of clock cycles taken for the execution of the above sequence of instructions is _______________________ .
$$P1:$$ Four-stage pipeline with stage latencies $$1$$ $$ns,$$ $$2$$ $$ns,$$ $$2$$ $$ns,$$ $$1$$ $$ns.$$
$$P2:$$ Four-stage pipeline with stage latencies $$1$$ $$ns,$$ 1$$.5$$ $$ns,$$ $$1.5$$ $$ns,$$ $$1.5$$ $$ns.$$
$$P3:$$ Five-stage pipeline with stage latencies $$0.5$$ $$ns,$$ $$1$$ $$ns,$$ $$1$$ $$ns,$$ $$0.6$$ $$ns,$$ $$1$$ $$ns.$$
$$P4:$$ Five-stage pipeline with stage latencies $$0.5$$ $$ns,$$ $$0.5$$ $$ns,$$ $$1$$ $$ns,$$ $$1$$ $$ns,$$ $$1.1$$ $$ns.$$
Which processor has the highest peak clock frequency?