NASM 2.05 based x86 Instruction Reference[ch186]
A.5.164 MOVHPD: Move High Packed Double-Precision FP MOVHPD xmm,m64 ; 66 OF 16 /r [WILLAMETTE,SSE2] MOVHPD m64,xmm ; 66 OF 17 /r [WILLAMETTE,SSE2] MOVHPD moves a double-precision FP value between the source and destination operands. One of the operands is a 64-bit memory location, the other is the high quadword of an XMM register. The operation of this instruction is: mem[0-63] := xmm[64-127]; or xmm[0-63] remains unchanged; xmm[64-127] := mem[0-63].