Memory Access Time [15 points]

Consider a MIPS processor that includes a cache, a main memory, and a hard drive.

Access times of cache memory, main memory, and hard drive are 5 ns, 200 ns, and

1000 ns, respectively. Assume that cache memory is divided into instruction cache and

data cache. Assume that data cache has a 90% hit rate. Assume that main memory

has a 98% hit rate and hard drive is perfect (it has a 100% hit rate).

Use the following formula for average access time calculations:

AMST = tcache + MRcache(tMM + MRMM tV M )

(b) How many clock cycle per instruction (CPI) on average are needed for load and

store word instructions.