Embedded C for Digital Signal Processing

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.