A.5.179 MOVSD: Move Scalar Double-Precision FP Value
MOVSD xmm1,xmm2/m64 ; F2 0F 10 /r [WILLAMETTE,SSE2]
MOVSD xmm1/m64,xmm2 ; F2 0F 11 /r [WILLAMETTE,SSE2]
MOVSD moves a double-precision FP value from the source operand to the
destination operand. When the source or destination is a register, the
low-order FP value is read or written.