Multimedia extensions for general-purpose processors

This paper gives an overview of the multimedia instructions that have been added to the instruction set architectures of general-purpose microprocessors to accelerate media processing. Examples are MAX, MMX and VIS, the multimedia extensions for PA-RISC, ix86, and SPARC processor architectures. We describe subword parallelism, a low overhead form of SIMD parallelism, and the classes of instructions needed to support subword parallel computations efficiently. Features described include arithmetic operations with saturation, averaging, multiply alternatives, data rearrangement primitives like Permute and Mix, formatting instructions, conditional execution, and complex instructions.