a-tions.</p>
<p>For non-VEX encoded instruction syntax and when the source and destination operands are XMM registers, the high quadword of the destination operand remains unchanged. When the source operand is a memory location and destination operand is an XMM registers, the high quadword of the destination operand is cleared to all 0s.</p>
<p>In 64-bit mode, use of the REX.R prefix permits this instruction to access additional registers (XMM8-XMM15).</p>
<p>Note: For the “VMOVSD m64, xmm1” (memory sto