t of merging the low quadword of the second source operand with the quad word in bits 127:64 of the first source operand. The upper bits of the destination operand are cleared.</p>
<h2>Operation</h2>
<p><strong>MOVSD (128-bit Legacy SSE version: MOVSD XMM1, XMM2)</strong></p>
<pre>DEST[63:0] ← SRC[63:0]
DEST[VLMAX-1:64] (Unmodified)</pre>
<p><strong>MOVSD/VMOVSD (128-bit versions: MOVSD m64, xmm1 or VMOVSD m64, xmm1)</strong></p>
<pre>DEST[63:0] ← SRC[63:0]</pre>
<p><strong>MOVSD (128-bit Legacy SSE ver