Implementation and evaluation of the Complex Streamed Instruction set

Abstract

An architectural paradigm designed to accelerate streaming operations on mixed-width data is presented and evaluated. The described Complex Streamed Instruction (CSI) set contains instructions that process data streams of arbitrary length. The number of bits or elements that will be processed in parallel is therefore not visible to the programmer, so no recompilation is needed in order to benefit from a wider datapath. CSI also eliminates many overhead instructions (such as instructions needed for data alignment and reorganization) often needed in applications utilizing media ISA extensions such as MMX and VIS by replacing them with a hardware mechanism. Simulation results using several multimedia kernels demonstrate that CSI provides a factor of up to 9.9 (4.0 on average) performance improvement when compared to Sun's VIS extension. For complete applications, the performance gain is 9% to 36% with an average of 20%.