Question

Figure 1: each block gives the number of different types of instructions

Consider a program with the execution flow shown in Figure 1. There are in total 3 types of instructions used in this program: 

• Type 1 (in-processor calculation): execution rate as 1 per clock cycle; 

• Type 2 (memory access): each instruction takes 2 clock cycles for execution; 

• Type 3 (loop control): each instruction takes 2 clock cycles for jump into the loop block or 3 clock cycles for jump to the block after loop. 

In statistics, for this program, the actual rounds of loop follows the probability distribution below 

Number of loops	Probability
0	10%
1	20%
2	30%
3	20%
4	10%
5	10%

Suppose this program is executed in a computer in which the clock rate for the processor is 1.6 MHz. In average, how long is the time (in μs) needed for executing the whole program by this computer? 

Answer 1