A Comparison of Register TransferLanguages
Mario R. Barbacci · 1975
Different notations havebeenpioposed overtheyears todescribe register transfer (RT)sygtems. Theyhavemetwithvary- ingdegrees ofsuccessandtoprovide a direct comparison ofthem isa difficult task. Oneofthereasonsforthisisthedifferent views oftheRT level ofdesign heldbytheproponents ofthelanguages. Theapproach usedinthis paperistoprovide a common ground, orkernel, fortheentities thelanguages trytodescribe. Thestarting point is,sincetheRT level isan abstraction oftheswitching circuit level, theability todescribe systems atthelowerlevel. Thenthe concepts introduced bytheRT level ofdesign, namely, theselec- tive control oftheactivities, ispresented. Atthispoint, a classifica- tionofthelanguages intoprocedural andnonprocedural isprovided. Thenextstepinthestudydealswiththeability ofthelanguages to denotethebehavior ofa setofasynchronous control modules. Thenextstepdeals withtheir usefulness todescribe complex sys- tems(e.g., instruction setprocessors) andtheway a description is organized toprovide different levels ofdetail. A fewremarksare madeabouttheir implementation forsimulation andautomatic de- signsystems. Finally, thelanguages are compared against a setof requirements forwriting behavioral andstructural descriptions of digital systems. IndexTerms-Asynchronous control, behavioral description, de- signautomation, designlanguages, language properties, register transfer level, structural description.