Function 1Ah    Display Combination Code                     (MCGA, VGA) 

		Using the compatibility BIOS of the PS/2 Models 50, 60, 80 there 

		is a way to determine which video controller and attached 

		display are on the system.  The Display Combination Code (DCC) 

		is a Video BIOS function that provides the capability. 

entry   AH      1Ah 

	AL      00h     read display combination code 

		01h     write display combination code 

return  AL      1Ah     indicates Compatibility BIOS is supported, 

			any other value is invalid 

	BH      Display Combination Code (DCC) 

		00h     no display 

		01h     IBM monochrome adapter and display 

		02h     IBM color/graphics monitor adapter w/color display 

		03h     reserved 

		04h     IBM EGA, color display 

		05h     IBM EGA, monochrome display 

		06h     IBM PGA, color display 

		07h     VGA, analog monochrome display 

		08h     VGA, analog color display 

		09h     reserved 

		0Ah     MCGA, digital color display 

		0Bh     MCGA, analog monochrome display 

		0Ch     MCGA, analog color display 

		0FFh    unknown display type 

	BL      active display device code 

note    This function may be used to test for VGA, since it is not supported in 

	earlier adapters. If AL is still 1Ah when the call completes, a VGA 

	compatible adapter is present. 

 

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