Intel ARCHITECTURE IA-32 - Manual (Page 234)

IA-32 Intel® Architecture Optimization
4-14
Insert Word
The pinsrw instruction loads a word from the lower half of a 32-bit
integer register or from memory and inserts it in the MMX technology
destination register at a position defined by the two least significant bits
of the immediate constant. Insertion is done in such a way that the three
other words from the destination register are left untouched, see
Figure 4-6 and Example 4-8.
Figure 4-5 pextrw Instruction
Example 4-7 pextrw Instruction Code
; Input:
; eax source value
; immediate value:“0”
; Output:
; edx 32-bit integer register containing the
; extracted word in the low-order bits &
; the high-order bits zero-extended
movq mm0, [eax]
pextrw edx, mm0, 0
O M15163
0 ..0 X1
M M
R32
31 0
31 0 63
X4 X3 X2 X1