 is indicated with the SYSENTER/SYSEXIT present (SEP) feature flag returned to the EDX register by the CPUID instruction. An operating system that qualifies the SEP flag must also qualify the processor family and model to ensure that the SYSENTER/SYSEXIT instructions are actually present. For example:</p>
<p>IF CPUID SEP bit is set</p>
<p>THEN IF (Family = 6) and (Model &lt; 3) and (Stepping &lt; 3)</p>
<p>THEN</p>
<p>SYSENTER/SYSEXIT_Not_Supported; FI;</p>
<p>ELSE</p>
<p>SYSENTER/SYSEXIT_Supported; FI;</p>