In today's embedded processors, performance and flexibility have become the two key attributes. These attributes are often conflicting. The best performance is obtained from custom designed integrated circuits. In contrast, the maximum flexibility is delivered by a general purpose processor. Among the architecture types emerged over the past years to strike an optimum balance between these two attributes, two are prominent. The first ones are Field Programmable Gate Array (FPGA)-based architectures and the second ones are Application Specific Instruction-set Processors (ASIPs).