INFO: Detecting EGA.SYS (78451)

SUMMARY

EGA.sys is a driver that facilitates the use of the shadow registers in EGA and more advanced video cards. Through the use of the mouse driver's Interrogate Driver function, it is possible to determine if EGA.sys is installed.

The interface to the Interrogate Driver function is as follows:

   AH = FAh
   BX = 0
   INT 10h
				

The return values are:

   AX = Restored
   BX = 0 if the mouse driver or EGA.SYS is not installed

   < 2 if EGA.SYS was installed with the mouse driver
   >= 2 if EGA.SYS was installed
				

For more information, see chapter 10 of the "Microsoft Mouse Programmer's Reference," second edition (Microsoft Press).