Intel 64 and IA-32 Architectures Software Developers Manual Volume 2B, Instruction Set Reference, N-Z

4-388 Vol. 2B
INSTRUCTION SET REFERENCE, N-Z
UNPCKLPD—Unpack and Interleave Low Packed Double-Precision
Floating-Point Values
Description
Performs an interleaved unpack of the low double-precision floating-point values
from the source operand (second operand) and the destination operand (first
operand). See Figure 4-17. The source operand can be an XMM register or a 128-bit
memory location; the destination operand is an XMM register.
When unpacking from a memory operand, an implementation may fetch only the
appropriate 64 bits; however, alignment to 16-byte boundary and normal segment
checking will still be enforced.
In 64-bit mode, using a REX prefix in the form of REX.R permits this instruction to
access additional registers (XMM8-XMM15).
Operation
DEST[63:0] ← DEST[63:0];
DEST[127:64] ← SRC[63:0];
Opcode Instruction
64-Bit
Mode
Compat/
Leg
Mode Description
66 0F 14
/r
UNPCKLPD xmm1,
xmm2/m128
Valid Valid Unpacks and Interleaves double-
precision floating-point values from
low quadwords of xmm1 and
xmm2/m128.
Figure 4-17. UNPCKLPD Instruction Low Unpack and Interleave Operation
X1
X0
Y1 Y0
Y0
X0
DEST
SRC
DEST