1. An apparatus, comprising: a decoder to decode a first instruction into a decoded first instruction, and a second instruction into a decoded second instruction; and an execution unit to execute the decoded first instruction and the decoded second instruction, said execution unit including the following: input register space to store a first data structure to be replicated when executing said decoded first instruction and to store a second data structure to be replicated when executing said decoded second instruction, said first and second data structures both being packed data structures, data values of said first packed data structure being twice as large as data values of said second packed data structure, replication logic circuitry to replicate said first data structure when executing said decoded first instruction to create a first replication data structure, and to replicate said second data structure when executing said decoded second instruction to create a second replication data structure, and masking logic circuitry to mask said first replication data structure at a first granularity and mask said second replication data structure at a second granularity, said second granularity being twice as fine as said first granularity.