VGA mode 0x13 in pmode

[HOS]

Hello,

without using the BIOS routines are their ports to write to or some other method to switch between 80x25 character mode and VGA graphics mode 0x13?

thanks

[Dreamsmith]

You can always switch from any one video mode to any other without using the BIOS. However, what I/O ports and/or memory mapped I/O locations you need to access will vary from card to card. If you have a Virtual-8086 monitor, you can log which I/O ports and such are being accessed by the BIOS to enable a particular video mode. OTOH, if you have a Virtual-8086 monitor, you don't need to bother...

That having been said, the good old-fashioned VGA video modes can usually be enabled in a fairly standard manner, due to backwards compatibility concerns with most video card makers. You might want to check here: http://my.execpc.com/~geezer/osd/graphics/modes.c

[HOS]

OK thank you, that looks like it will do what i want to do... i tried searching for a vga specification - does such a thing exist? something that says what each byte going to each port does? or is it better to mimic and not ask questions?

[Colonel Kernel]

This is a pretty good reference:

http://osdev.neopages.net/FreeVGA/vga/vga.htm

Unfortunately, it doesn't have anything like a "how-to" on mode switching (I've been looking for the same thing recently). But with the above reference, it ought to be possible to figure out what the sample code is doing... hopefully...

[bubach]

This might help:
http://osdev.neopages.net/FreeVGA/vga/portidx.htm(oops, already posted)
http://alexfru.narod.ru/miscdocs/ega_vga/tauron30.zip

/ Christoffer