Method and apparatus for constant generation in SIMD processing

A method of generating a constant comprising the steps of:

• storing a plurality of data elements within a register data store;
• decoding a constant generating, single instruction multiple data (SIMD) instruction, said constant generating SIMD instruction having an associated data value with a data portion and a control portion, said associated data value being encoded within said SIMD instruction;
• performing SIMD data processing operations within parallel processing lanes on multiple data elements included in at least one source operand with each of the multiple data elements corresponding to one of said multiple parallel processing lanes in response to a decoded SIMD data processing instruction such that a data processing operation specified by said decoded SIMD instruction is performed on each of the multiple data elements in the corresponding parallel processing lane;
• generating, in response to said decoded SIMD constant generating instruction, said constant by expanding at least the data portion of said associated data value in dependence on a selected function by replicating said data portion at different places within said generated constant, in response to said selected function, said control portion specifying at least one position within said constant where said data portion is to be replicated;
• and
• forming said at least one source operand from said generated constants
• wherein replicating said data portion forms multiple constants with one of those constants being used in a SIMD data processing operation performed on each data element in multiple ones of the multiple processing lanes.