INT 0x10 - 0x1c - Save/Restore Video State (VGA only)

Request/Call:

reg	value	descr
AH	0x1c
AL	0x00 0x01 0x02	0x00 : Get Save buffer size 0x01 : Save requested states 0x02 : restore requested states

return

AL = 0x1C if function supported

Return

reg	descr
AL	0x1C
BX	buffer size in 64 byte blocks

reg	Descr
CX	requested states (see AL = 0)
ES:BX	pointer to buffer

Return

nothing

reg	Descr
CX	requested states (see AL = 0)
ES:BX	pointer to buffer

Return

nothing

Bit(s)	Description
0	video hardware (see bellow)
1	BIOS data areas
2	color registers and DAC state (see bellow)
3-15	unused (0)

Offset	Size	Description
00h	BYTE	sequencer index register
01h	BYTE	CRTC index register
02h	BYTE	graphics controller index register
03h	BYTE	attribute controller index register
04h	BYTE	feature controller register
05h	4 BYTEs	sequencer registers
09h	BYTE	sequencer register 0
0Ah	25 BYTEs	CRTC registers 0-8
23h	16 BYTEs	palette registers 00h-0Fh
33h	4 BYTEs	attribute registers 10h-13h
37h	9 BYTEs	graphics controller registers 0-8
40h	BYTE	CRTC base address (low)
41h	BYTE	CRTC base address (high)
42h	BYTE	plane 0 latch
43h	BYTE	plane 1 latch
44h	BYTE	plane 2 latch
45h	BYTE	plane 3 latch

many BIOSes corrupt the video registers when saving the state, so a program should restore the state immediately after saving it (the saved data is uncorrupted)
the BIOS data area consists of the 96 bytes from 040h:0049h-00A8h
this function is not supported when DOS/V is running
this function may be a better VGA installation check than the usual INT 10/AX=1A00h, since some late-model EGA cards (such as the ATI EGA Wonder) supported that call