            MASK ← 0000FFFF00000000H;
              SEL ← 3:
                              MASK ← FFFF000000000000H;
    DEST ← (DEST AND NOT MASK) OR (((SRC &lt;&lt; (SEL ∗ 16)) AND MASK);</pre>
<p><strong>PINSRW (with 128-bit source operand)</strong></p>
<pre>    SEL ← COUNT AND 7H;
         CASE (Determine word position) OF
              SEL ← 0:
                              MASK ← 0000000000000000000000000000FFFFH;
              SEL ← 1:
                              MASK ← 00000000