Study On The Automatic Recognition Of Subword-Parallelism In Multimedia Programs

Along with the occurrence of abundant multimedia information,modern computers are demanded to own excellent ability of multimedia processing.The most prominent characteristic of multimedia application program is its intrinsic parallelism,called subword parallelism,which means several data units can be processed simultaneously.In order to utilize parallelism,the majority of computer architecture designs achieve subword parallelism operation by the means of expanding instruction sets with multimedia instructions, however,the bottle-neck of this method is how to make the compiler produce effective codes.Therefore,how to distinguish subword parallelism instruction from the common serial C programs becomes one of the frontier research topics currently.This article is devoted to sub-word parallelism analysis of serial C program of image-processing algorithms.To begin with,we delineated the common multimedia program MediaBench and its thirteen typical application programs,introduced the structure and simulative flowsheet of the simulator SimpleScalar,and on this basis carried out the character analysis of multimedia application program.Then we explored the parallel characteristics of multimedia application program from the microscopic aspect.Furthermore,we designed a kind of generating method of serial image-processing algorithms on the basis of flow graph program generating to solve the problem that the present compilation technique is hardly able to exploit and locate the Sub-Word parallel from the program basic blocks.This method includes three parts.First,the improved multi-dimensional dataflow,namely SWFG(Sub-Word Flow Graph),is able to explicitly model sub-word parallelism in serial C programs.Second,based on graph patten recognition, parallel visiting models are identified and exploited from dataflow graphs,explicit Sub-Word Flow Graph are presented, and as a result parallel generating procedure of serial programs are completed.Third,based on the generated displayed Sub-Word Flow Graph,instruction selections are carried out to achieve the key part of code automatic generation.