A.5.209 PEXTRW: Extract Word
PEXTRW reg32,mm,imm8 ; 0F C5 /r ib [KATMAI,MMX]
PEXTRW reg32,xmm,imm8 ; 66 0F C5 /r ib [WILLAMETTE,SSE2]
PEXTRW moves the word in the source register (second operand) that is
pointed to by the count operand (third operand), into the lower half of
a 32-bit general purpose register. The upper half of the register is
cleared to all 0s.
When the source operand is an MMX register, the two least significant
bits of the count specify the source word. When it is an SSE register,
the three least significant bits specify the word location.