AMD x86-64 Architecture Programmer's Manual, Volume 4, 128-Bit ...

AMD64 Technology 26568—Rev. 3.05—September 2003
PEXTRW Extract Packed Word
Extracts a 16-bit value from an XMM register, as selected by the immediate byte
operand (as shown in Table 1-2) and writes it to the low-order word of a 32-bit generalpurpose
register, with zero-extension to 32 bits.
Mnemonic Opcode Description
PEXTRW reg32, xmm, imm8 66 0F C5 /r ib Extracts a 16-bit value from an XMM register and writes it to
low-order 16 bits of a general-purpose register.
Table 1-2. Immediate-Byte Operand Encoding for 128-Bit PEXTRW
Immediate-Byte
Bit Field
2–0
32
0
reg32 xmm
imm8
7 0
mux
248 PEXTRW
15
0
127 112 111 96 95 80 79 64 63 48 47 32 31 16 15 0
pextrw-128.eps
Value of Bit Field Source Bits Extracted
0 15–0
1 31–16
2 47–32
3 63–48
4 79–64
5 95–80
6 111–96
7 127–112