r bits (VLMAX-1:128) of the corresponding YMM register destination are unmodified.</p>
<p>VEX.128 encoded version: the first source operand is an XMM register or 128-bit memory location. The destination operand is an XMM register. The upper bits (VLMAX-1:128) of the destination YMM register destination are zeroed.</p>
<p>VEX.256 encoded version: The first source operand is a YMM register. The second source operand can be a YMM register or a 256-bit memory location. The destination operand is a YMM register.