RealView Compilation Tools Developer Guide - ARM Information ...

Embedded Software Development
2.1 About embedded software development
Most embedded applications are initially developed in a prototype environment with
resources that differ from those available in the final product. Therefore, it is important
to consider the processes involved in moving an embedded application from one that
relies on the facilities of the development or debugging environment to a system that
runs standalone on target hardware.
When developing embedded software using RVCT, you must consider the following:
• How the C library uses hardware.
• Some C library functionality executes by using debug environment resources. If
used, you must re-implement this functionality to make use of target hardware.
• RVCT has no inherent knowledge of the memory map of any given target. You
must tailor the image memory map to the memory layout of the target hardware.
• An embedded application must perform some initialization before the main
application can be run. A complete initialization sequence requires code that you
implement in addition to RVCT C library initialization routines.
2.1.1 Example code
To illustrate the topics covered in this chapter, associated example projects are provided.
The code for the Dhrystone builds described in this chapter is in the main examples
directory, in ...\emb_sw_dev. Each build is in a separate directory, and provides an
example of the techniques described in successive sections of this chapter. Specific
information regarding each build can be found in:
• Example code for Build 1 on page 2-11
• Example code for Build 2 on page 2-14
• Example code for Build 3 on page 2-22
• Example code for Build 4 on page 2-34
• Example code for Build 5 on page 2-37.
The Dhrystone benchmarking program provides the code base for the example projects.
Dhrystone was chosen because it enables many of the concepts described in this chapter
to be illustrated.
The example projects are tailored to run on the ARM ® Integrator development
platform. However, the principles illustrated by the examples apply to any target
hardware.
2-2 Copyright © 2002-2007 ARM Limited. All rights reserved. ARM DUI 0203H
Non-Confidential