NASM 2.05 based x86 Instruction Reference[ch185]
A.5.163 MOVHLPS: Move Packed Single-Precision FP High to Low MOVHLPS xmm1,xmm2 ; OF 12 /r [KATMAI,SSE] MOVHLPS moves the two packed single-precision FP values from the high quadword of the source register xmm2 to the low quadword of the destination register, xmm2. The upper quadword of xmm1 is left unchanged. The operation of this instruction is: dst[0-63] := src[64-127], dst[64-127] remains unchanged.