Chapter 5, Problem 5.19HW

Program Plan Intro

Given C Code:

void psum1a(float a[], float p[], long n)

{

long i;

float last_val, val;

last_val = p[0] = a[0];

for(i=1; i<n; i++)

{

val = last_val + a[i];

p[i] = val;

last_val = val;

}

}

Cycles per element (CPE):

• The CPE denotes performance of program that helps in improving code.
• It helps to understand detailed level loop performance for an iterative program.
• It is appropriate for programs that use a repetitive computation.
• The processor’s activity sequencing is controlled by a clock that provides regular signal of some frequency.

Loop unrolling:

• It denotes a program transformation that would reduce count of iterations for a loop.
• It increases count of elements computed in each iteration.
• It reduces number of operations that is not dependent to program directly.
• It reduces count of operations in critical paths of overall computations.