Single-instruction multiple-data vector permutation instruction and method for performing table lookups for in-range index values and determining constant values for out-of-range index values

Abstract

A processor in a data processing system executes a permutation instruction which identifies a first source register, at least one other source register, and a destination register. The first source register stores at least one in-range index value for the at least one other source register and at least one out-of-range index value for the at least one other source register. The at least one other source register stores a plurality of vector element values, wherein each in-range index value indicates which vector element value of the at least one other source register is to be stored into a corresponding vector element of the destination register. Each out-of-range index value is used to indicate which one of at least two predetermined constant values is to be stored into a corresponding vector element of the destination register. Partial table lookups using a permutation instruction shortens the time required to retrieve data.