Issue No. 11 - November (1984 vol. 33)
S. Weiss , Department of Computer Sciences, University of Wis-consin
Basic principles and design tradeoffs for control of pipelined processors are first discussed. We concentrate on register-register architectures like the CRAY-1 where pipeline control logic is localized to one or two pipeline stages and is referred to as "instruction issue logic." Design tradeoffs are explored by giving designs for a variety of instruction issue methods that represent a range of complexity and sophistication. These vary from the CRAY-1 issue logic to a version of Tomasulo's algorithm, first used in the IBM 360/91 floating point unit. Also studied are Thornton's "scoreboard" algorithm used on the CDC 6600 and an algorithm we have devised. To provide a standard for comparison, all the issue methods are used to implement the CRAY-1 scalar architecture. Then, using a simulation model and the Lawrence Livermore Loops compiled with the CRAY Fortran compiler, performance results for the various issue methods are given and discussed.
Tomasulo's algorithm, CDC 6600 scoreboard, control logic, CRAY-1, IBM 360/91, instruction issue logic, performance simujation, pipelined computers, supercomputers
S. Weiss and J. Smith, "Instruction Issue Logic in Pipelined Supercomputers," in IEEE Transactions on Computers, vol. 33, no. , pp. 1013-1022, 1984.