MMX instruction to unpack
packed words to
packed dwords.
This instruction interleaves the bottom 2 words of the source (a
MMX register or
64 bit memory location) into the bottom words of the destination (a MMX register). Example: if the source consists of abcdefgh and the destination contains stuvwxyz, the new destination contents are efwxghyz.
Compare:
PUNPCKLBW,
PUNPCKLDQ