A Linear Complexity Algorithm for the Generation of Multiple Input Single Output Instructions of Variable Size

The Instruction-Set extension problem has been one of the major topics in the last years and it is the addition of a set of new complex instructions to a given Instruction-Set. This problem in its general formulation requires an exhaustive search of the design space to identify the candidate instructions. This search turns into an exponential complexity of the solution. In this paper we propose an algorithm for the generation of Multiple Input Single Output instructions of variable size which can be directly selected or combined for Instruction-Set extension. Additionally, the algorithm is suitable for inclusion in a design flow for automatic generation of MIMO instructions. The proposed algorithm is not restricted to basic-block level and has linear complexity with the number of processed elements.