Embedded systems are of great economic importance. Embedded applications include consumer electronics appliance, signal processing, automobile control, aircraft autopilot, and so on. It is estimated that the embedded system market sales was approximately $46 billion in 2004 and expected to grow at an average rate of 14% over the next five years to reach $88 billion by 2009. Compared to general-purpose computing systems, embedded systems are more cost sensitive and require shorter time-to-market. To reduce the design effort and the cost of the system and shorten the time-to-market, the designer has to come up with a heterogeneous system, which usually consists of embedded processors and ASICs. Most embedded systems are heterogeneous multiprocessors with several different types of processing elements, including customized hardware processing elements as well as programmable CPUs, and hardware/software co-design is necessary to design embedded systems.