APPARATUS AND METHOD FOR RIGHT-SHIFTING PACKED QUADWORDS AND EXTRACTING PACKED WORDS

摘要

An apparatus and method for performing right-shifting operations on packed quadword data. For example, one embodiment of a processor comprises: a decoder to decode a right-shift instruction to generate a decoded right-shift instruction; a first source register to store a plurality of packed quadword data elements, each of the packed quadword data elements including a sign bit; execution circuitry to execute the decoded right-shift instruction, the execution circuitry comprising shift circuitry with sign preservation logic to right-shift first and second packed quadword data elements from first and second packed quadword data element locations, respectively, in the first source register by an amount specified in an immediate value or in a control value in a second source register, the right-shifting to generate first and second right-shifted quadwords, the sign preservation logic to shift in the sign bit to any bit positions exposed by the right-shifting of the first and second quadwords; the execution circuitry to cause selection of 16 most significant bits of the first and second right-shifted quadwords, including the sign bit, to be written to 16 least significant bit regions of first and second quadword data element locations, respectively, of a destination register.