Apparatus and method for shifting left quadwords and extracting packed double words

摘要

The invention relates to a processor for performing right-shift operations on packed quadword data. The processor decodes and stores a plurality of packed quadword data elements in a first source register, each of the packed quadword data elements including a sign bit. It executes a decoded left shift instruction to shift left the packed quadword data items from their respective location in the first source register by an amount specified in an immediate value or in a control value in a second source register. Zeros are written in the bit positions exposed by the left shift of the packed quadword data elements; and a copy of the sign bit is maintained. The 32 most significant bits of the left-shifted quadwords, including the sign bit, are written into the 32 least significant bit areas of the locations of the respective quadword data element of a destination register, with the sign bit written to the most significant bit position of each of the 32 least significant bit areas.