Problem $2$:Problem $5$:

You are going to enhance a computer, and there are two possible improvements: either make multiply instructions

run three times faster than before or make memory access instructions run four times faster than before. You

repeatedly run a program that takes $400$ seconds to execute. Of this time, $25\%$ is used for multiplication, $35\%$ for

memory access instructions, and $40\%$ for other tasks. What will the speedup be if you improve only multiplication?

What will the speedup be if you improve only memory access? What will the speedup be if both improvements are

made? Use Amdahl's law.

You are the lead designer of a new processor having a clock rate of $800MHz.$ The processor design and compiler are

complete. Call this base computer Mbase. For Mbase, the following measurements were made using a simulator:

The hardware engineering team claims that it can improve the processor design to give it a clock rate of $1GHz.$ Call

this computer Mopt. For Mopt, the following measurements were made using a simulator:

The compiler team proposes to improve the compiler instead. Call this combination of the improved compiler and

the base computer Mcomp. The instruction improvements from this enhanced compiler were estimated as follows:

For example, if the base computer executed $500$ class A instructions, Mcomp would execute $0\mathrm{.}80500=400$ class

A instructions for the same program.

Finally, there is also the possibility of combining both processor design and compiler improvements. Call this

combination Mboth.

a$.$ What is the CPI for each computer?

b$.$ What are the native MIPS ratings for each computer?

c$.$ How much faster is Mopt than Mbase.

d$.$ How much faster is Mcomp than Mbase.

e$.$ How much faster is Mboth than Mbase.