User Guide

158 128-Bit Media and Scientific Programming
AMD64 Technology 24592—Rev. 3.15—November 2009
The MOVAPx instructions copy a vector of four single-precision floating-point values (MOVAPS) or a
vector of two double-precision floating-point values (MOVAPD) from the second operand to the first
operand—i.e., from an XMM register or 128-bit memory location or to another XMM register, or vice
versa. A general-protection exception occurs if a memory operand is not aligned on a 16-byte
boundary.
The MOVUPx instructions perform operations analogous to the MOVAPx instructions, except that
unaligned memory operands do not cause a general-protection exception.