PEXTRW
Usage: PEXTRW dest,src,count Modifies flags: None
Copies the word in the 'src' specified by the 'count' (third operand) to the 'dest' operand.
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.
The 'src' operand can be an MMX technology register or an XMM register. The 'dest' operand is the low word of a general-purpose register. The 'count' operand is an 8-bit immediate. When specifying a word location in an MMX technology register, the 2 least-significant bits of the 'count' operand specify the location; for an XMM register, the 3 least-significant bits specify the location. The high word of the 'dest' operand is cleared (set to 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.
EXAMPLE:
pextrw ecx xmm1 2