INT 10h,  12h (18)       Alternate Select                                 EGA

Returns information on the Enhanced Display Adapter (EGA) and allows
the selection of an alternative EGA Print Screen routine.

On entry:      AH         12h
BL         Subservice
10h - Return EGA information
20h - Select alternative EGA Print Screen

Returns:       (for Subservice 10h only):
BH         Display mode in effect
00h    Color mode (3Dxh address range)
01h    Monochrome mode (3Bxh address range)
BL         EGA memory
00h    64K
01h    128K
02h    192K
03h    256K
CH         Adapter bits
CL         Switch setting


Notes:         The value returned in CL (Switch setting) represents
the DIP switch settings on the EGA. The Adapter bits
(CH) is defined as follows:

    Adapter bits (CH)

7 6 5 4 3 2 1 0
x x x x . . . .       Unused
. . . . x x . .       Reserved
. . , . . . x .       FEAT1 (pin 17)
. . . . . . . x       FEAT0 (pin 19)

To print the screen contents when the number of rows
changes, use Subservice 20h (Set Alternative Print
Screen) to install a Print Screen routine that will
work correctly with the row change.

See also: INT 10h, 11h

INT 10h, 12h (18) Alternate Select EGA