Morphable Structures for Reconfigurable Instruction Set Processors

This paper presents a novel methodology for instruction set customization of RISPs (Reconfigurable Instruction Set Processors) using morphable structures. A morphable structure consists of a group of hardware operators chained together to implement a restricted set of custom instructions. These structures are implemented on the reconfigurable fabric, and the operators are enabled/disabled on demand. The utilization of a predefined set of morphable structures for instruction set customization dispenses the need for hardware synthesis in design exploration, and avoids run-time reconfiguration while minimizing the reconfigurable area. We will describe the two stages of the methodology for constructing the morphable structures, namely template generation and identification of a maximal unique pattern set from the templates. Our preliminary studies show that 23 predefined morphable structures can sufficiently cater to any application in a set of eight MiBench benchmark applications. In addition, to achieve near-optimal performance, the maximum required number of morphable structures for an application is only 8.