SVGA, function 04 ?

[Jark]

I got this from a Ralf' Interrupt's list.

Any of you ever used this function ? Could he/she explain the details (e.g. size of the buffer?). Can this function help about my issues with XP... ?

INT 10 - VESA SuperVGA BIOS - SAVE/RESTORE SuperVGA VIDEO STATE
AX = 4F04h
DL = subfunction
00h get state buffer size
Return: BX = number of 64-byte blocks needed
01h save video states
ES:BX -> buffer
02h restore video states
ES:BX -> buffer
CX = flags for states to save/restore
bit 0: video hardware state
bit 1: video BIOS data state
bit 2: video DAC state
bit 3: SuperVGA state
Return: AL = 4Fh function supported
AH = status
00h successful
01h failed

[Glenn]

current state of your video board in a buffer area. You have to create the buffer area, e.g., by defining an array. You could then use the DL = 2 subfunction to restore that video state later (perhaps after you did something to change it). If you're going to do that, however, you need to know how large of an array to create. You'd use the DL = 0 subfunction to get that. I don't see what it has to with XP, though.

[Jark]

I won't probably help much, but I'm just wondering why switching to Screen 12 or 13 doesn't mess up the XP screen, while switching to an SVGA mode through an interrupt does... So I looked for a way to save&restore the situation before switching mode to ensure a clean come-back from QB to XP...

[Antoni Gual]

I bet that saving the situation before entering SVGA modes will probably save nothing..

[TheBigBasicQ]

I bet that saving the situation before entering SVGA modes will probably save nothing..

Yeah, I agree it saves nothing. But how did u get a VESA mode to work in XP?

[Jark]

I use QB with XP the same way as with the other versions of Windows, but the ATI technology of my Compaq is not happy with that when I come back to XP after running an SVGA application with QB...

[Jark]

I was trying to use that 04 function yesterday, but I can't see any DL parameter in the classical regs type.

Glenn ? Help!!!!!!

[Plasma]

dx = dh * 256 + dl
dl = dx and 255
dh = dx \ 256

[Jark]

I was almost sure "L" stood for "low", but it's far from guessing to making. Thanks!