entry16.inc code doubt

Hi,

Could someone please tell me what exactly
these two lines in the entry16.inc for i386 architecture
is doing 
***Extract***
    andl	$0x7FFAFFD1, %eax /* PG,AM,WP,NE,TS,EM,MP = 0 */
    orl	$0x60000001, %eax /* CD, NW, PE = 1 */

***Extract End***

What is the reference for this ..

Thanks and Regards
Deepak