Your company has a benchmark that is considered representative of your typical applications. An embedded processor under consideration to support your task does not have a floating-point unit and must emulate each floating-point instruction by a sequence of integer instructions. This processor is rated at 120 MIPS on the benchmark. A third-party vendor offers a compatible coprocessor to boost performance. That coprocessor executes each floating point instruction in hardware (i.e., no emulation is necessary). The processor/coprocessor combination rates 80 MIPS on the same benchmark. The following symbols are used to answer parts (a)-(e) of this exercise:
I - Number of integer instructions executed on the benchmark
F - Number of floating-point instructions executed on the benchmark.
Y - Number of integer instructions to emulate on floating-point instruction.
W - Time to execute the benchmark on the processor alone.
B - Time to execute the benchmark on the processor/coprocessor combination.
a) Write an equation for the MIPS rating of each configuration using the symbols above.
b) For the configuration without the coprocessor, we measure that F = 8 X 106, Y = 50, and W = 4 seconds. Find I.
c) What is the value of B?
d) What is the MFLOPS rating of the system with the coprocessor?
e) Your colleague wants to purchase the coprocessor even though the MIPS rating for the configuration using the coprocessor is less than that of the processor alone. Is your colleague's evaluation correct? Defend your answer.