Digital Signal Processing Reference
In-Depth Information
Embedded C for Digital Signal Processing
Bryan E. Olivier
Abstract
The majority of micro processors in the world do not sit inside a
desktop personal computer or laptop as general purpose processor, but have a
dedicated purpose inside some kind of apparatus, like a mobile telephone, modem,
washing machine, cruise missile, hard disk, DVD player, etc. Such processors
are called embedded processors. They are designed with their application in
mind and therefore carry special features. With the high volume and strict real
time requirements of mobile communication the digital signal processor (DSP)
emerged. These embedded processors featured special hardware and instructions
to support efficient processing of the communication signal. Traditionally these
special features were programmed through some assembly language, but with the
growing volume of devices and software a desire arose to access these features
from a standardized programming language. A work group of the International
Organization for Standardization (ISO) has recognized this desire and came up with
an extension of their C standard to support those features. This chapter intends to
explain this extension and illustrate how to use them to efficiently use a DSP.
1
Introduction
Traditionally the core algorithms in digital signal processing are programmed in
assembly or by using intrinsics because this gives access to the special features
offered by dedicated digital signal processors (DSP). These algorithms are becom-
ing increasingly complex, because of error correction and encryption requirements.
This increasing complexity makes the tradition of programming in assembly or
