Design of arithmetic elements for Burroughs Scientific Processor

The design criteria and implementation of the Arithmetic Element (AE) of the Burroughs Scientific Processor, a vector machine intended for scientific computation requiring speed of up to 50 million floating-point operations per second, is discussed. An array of 16 AEs operate in lockstep mode, executing the same instruction on 16 sets of data. The 16 AEs are one stage in a pipeline which consists of 17 memory modules, an input alignment network, and an output alignment network. The AE itself is not pipelined. It can perform over one hundred different operations including a floating-point addition, subtraction and multiplication, division, square root, among the others. Eight registers are provided for the storage of intermediate values and results. Modulo 3 residue arithmetic is used for checking hardware failures.