AMD 64-Bit Technology - ECE User Home Pages

26568—Rev. 3.02—August 2002
AMD 64-Bit Technology
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.
reg32
xmm
32
15
0
127 112 111 96 95 80 79 64 63 48 47 32 31 16 15 0
0
imm8
7 0
mux
pextrw-128.eps
Table 1-2.
Immediate-Byte Operand Encoding for 128-Bit PEXTRW
Immediate-Byte
Bit Field
Value of Bit Field
Source Bits Extracted
0 15–0
1 31–16
2 47–32
2–0
3 63–48
4 79–64
5 95–80
6 111–96
7 127–112
PEXTRW 247