Loop Realization And Optimization Based On X Stream Processor

With the wide application of image processing, fluid dynamics, and multimedia, stream processor takes greater part in the processor designing domain because of it's ability to exploit data level parallelism greatly. In X stream processor, many operate cluster which have the same structure deal with datum of the input streams periodically, based on the idea of Single Instruction and Multi Data (SIMD). Thus, sound loop realization and optimization mechanisms are of the first importance.Because of it's multiformity, X stream processor can't adopt the idea of"one instruction alone realizes a loop mode"as the traditional loop realization mechanism does. Otherwise, it may lead to much waste of hardware recourses. So we take the idea of separating the condition estimation and the loop jump, setting instructions respectively for this two parts and then assembling those two parts freely. And cover up with all the end up modes to meet the particularity, by designing a perfect instruction set.Furthermore, because of the strictly limited micro code in X stream processor, a software pipelining realization mechanism which releases the storage space pressure by concealing the"fill in"and"finish up"parts seemingly is presented, as well as the hardware implementation.We also research two kinds of commonly used techniques-software pipelining and loop unrolling, which turns the loop level, especially the nested loop level parallelism into the instruction level parallelism. Considering that the compile technique for X stream processor only supports selecting unrolling factors for nested loops artificially, arithmetic of automatically selecting unrolling factors for nested loops is presented, and also its realization with C language,. The result of Experiment shows that it can attain sound effect.In the end, the correctness and validity of all these techniques get proved by running loop programs on the all-purpose testing model for X stream processor. The loop realization and optimization techniques are adopt in the X stream processor implementation, and sound effect is attained.We complete the hardware implementation of loop realization and optimization, and lay a foundation for the further research of the compile techniques for X stream processor.