.128 encoded version: The source operand is an XMM register or 64- bit memory location. The destination operation is an XMM register. The upper bits (VLMAX-1:128) of the corresponding YMM register destination are zeroed.</p>
<p>VEX.256 encoded version: The source operand is a YMM register or 128- bit memory location. The destination operation is a YMM register.</p>
<p>Note: In VEX-encoded versions, VEX.vvvv is reserved and must be 1111b, otherwise instructions will #UD.</p>
<p>X3</p>
<p>X2</p>
<p>X1</p>
<p>