A Versatile Mechanism to Move Data in an Array Processor

Selection of elements and alignment of operands are fundamental operations on data, just as are arithmetic operations. Whereas sophisticated algorithms have been devised for the latter, vector processors usually lack a flexible and efficient routing unit. This is especially true of SIMD computers, to which the present study is devoted. Examples of required manipulations are: transfer, shift, diffusion, compression, expansion, mesh, perfect shuffle, and bit reversal. Using a method described in a previous paper of ours [15] we present algorithms to control a Benes network and perform these manipulations on vectors whose length is equal to the number of processing elements. Then we dispense with this constraint and propose a mechanism to rearrange vectors of any size, stored according to several schemes.