to 0 when the NW flag is set to 1).</p>
<p>If an attempt is made to change CR4.PCIDE from 0 to 1 while CR3[11:0] ≠ 000H.</p>
<p>If an attempt is made to clear CR0.PG[bit 31] while CR4.PCIDE = 1.</p>
<p>If an attempt is made to write a 1 to any reserved bit in CR3.</p>
<p>If an attempt is made to leave IA-32e mode by clearing CR4.PAE[bit 5].</p></td></tr>
<tr>
<td>#UD</td>
<td>
<p>If the LOCK prefix is used.</p>
<p>If an attempt is made to access CR1, CR5, CR6, or CR7.</p></td></tr></table>
<h2>64-Bit Mode