User Guide

160 128-Bit Media and Scientific Programming

AMD64 Technology 24592—Rev. 3.15—November 2009

64-bit memory location. In the memory-to-register case, the low-order 64 bits of the destination XMM

The MOVLPS and MOVLPD instructions copy a vector of two single-precision floating-point values

(MOVLPS) or one double-precision floating-point value (MOVLPD) from a 64-bit memory location

to the low-order 64 bits of an XMM register, or from the low-order 64 bits of an XMM register to a 64-

bit memory location. In the memory-to-register case, the high-order 64 bits of the destination XMM

The MOVHLPS instruction copies a vector of two single-precision floating-point values from the

high-order 64 bits of an XMM register to the low-order 64 bits of another XMM register. The high-

order 64 bits of the destination XMM register are not modified. The MOVLHPS instruction performs

an analogous operation except in the opposite direct (low-order to high-order), and the low-order 64

bits of the destination XMM register are not modified.

The MOVSS instruction copies a scalar single-precision floating-point value from the low-order 32

bits of an XMM register or a 32-bit memory location to the low-order 32 bits of another XMM register,

or vice versa. If the source operand is an XMM register, the high-order 96 bits of the destination XMM

the destination XMM register are cleared to all 0s.

The MOVSD instruction copies a scalar double-precision floating-point value from the low-order 64

bits of an XMM register or a 64-bit memory location to the low-order 64 bits of another XMM register,

or vice versa. If the source operand is an XMM register, the high-order 64 bits of the destination XMM

destination XMM register are cleared to all 0s.

The above MOVSD instruction should not be confused with the same-mnemonic MOVSD (move

string doubleword) instruction in the general-purpose instruction set. Assemblers distinguish the two

instructions by their operand data types.

Move with Duplication. These instructions move two copies of the affected data segments from the

source XMM register or 128-bit memory operand to the target destination register.

The MOVDDUP moves one copy of the lower quadword of the source operand into each quadword

half of the destination operand.

The MOVSLDUP instruction moves two copies of the first doubleword of the source operand into the

first two doubleword segments of the destination operand and moves two copies of the third

doubleword of the source operand into the third and fourth doubleword segments of the destination

operand.

The MOVSHDUP instruction moves two copies of the second doubleword of the source operand into

the first two doubleword segments of the destination operand and moves two copies of the fourth

doubleword of the source operand into the upper two doubleword segments of the destination operand.