Solved

Loop unrolling

Posted on 2002-07-01
1
268 Views
Last Modified: 2010-04-15
What are loop overheads? How are they overcome by unrolling?

Please let me know

Thanks,
Arut
0
Comment
Question by:arut
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 86

Accepted Solution

by:
jkr earned 100 total points
ID: 7121621
A 'loop overhead' is e.g.

int i;

for ( i = 0; i < 3; i++) {

 printf ( "i: %d\n", i);
}

Here, checking whether 'i' is smaller than 3 is the overhead.

'Unrolling' would make it

 printf ( "i: %d\n", i);
 printf ( "i: %d\n", ++i);
 printf ( "i: %d\n", ++i);

thus avoiding the overhead. But, you can also see the limitations if the loop bound is not constant.
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Preface I don't like visual development tools that are supposed to write a program for me. Even if it is Xcode and I can use Interface Builder. Yes, it is a perfect tool and has helped me a lot, mainly, in the beginning, when my programs were small…
This tutorial is posted by Aaron Wojnowski, administrator at SDKExpert.net.  To view more iPhone tutorials, visit www.sdkexpert.net. This is a very simple tutorial on finding the user's current location easily. In this tutorial, you will learn ho…
The goal of this video is to provide viewers with basic examples to understand and use pointers in the C programming language.
The goal of this video is to provide viewers with basic examples to understand how to create, access, and change arrays in the C programming language.

728 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question