The goal of this project is to have a LGPL'd Video Bios in Bochs and QEMU. This VGA Bios is very specific to the emulated VGA card. It is NOT meant to drive a physical vga card.
The Bochs VBE extension and it's Bochs device backend has been written by Jeroen Janssen (japj). It implements support for VBE version 2.0.
The Cirrus SVGA extension is designed for the Cirrus emulation in Bochs and QEMU. The initial patch for the Cirrus extension has been written by Makoto Suzuki (suzu).
The Voodoo Banshee PCI extension is designed for the Banshee emulation in Bochs. Some parts of the initial version are based on the Cirrus extension code.
To compile the VGA Bios you will need the following packages:
- make
- gcc (for 'biossums', 'vbetables-gen' and VGABIOS preprocessing)
- dev86 (bcc, as86)
Untar the archive, and type 'make'. You should get this set of binary files: "VGABIOS-lgpl-latest.bin", "VGABIOS-lgpl-latest-debug.bin", "VGABIOS-lgpl-latest-cirrus.bin", "VGABIOS-lgpl-latest-cirrus-debug.bin" and "VGABIOS-lgpl-latest-banshee.bin". Alternatively, you can use one of the precompiled binary files present in the archive.
Edit your bochs config file, and modify the 'vgaromimage' directive to point it to the VGABIOS image you want to use.
You can get a very basic debugging system: the VGABIOS sends messages to a usually unused ISA i/o port. The emulator prints the received characters to log file or console. In Bochs the "unmapped" device plugin must be loaded. It registers the VGABIOS info port 0x500.
VGABIOS images compiled with the DEBUG symbol set, will use the "printf" function to write the messages to the info port.
Look at the "testvga.c" file in the archive. This is a minimal Turbo C 2.0 source file that calls a few int10 functions. Feel free to modify it to suit your needs.
The original version of this program has been written by Christophe Bothamy. It is protected by the GNU Lesser Public License, which you should have received a copy of along with this package.
The VGA Bios has been written without reverse-engineering any existing Bios.
The source code contains code ripped from rombios.c of plex86, written by Kevin Lawton kevin2001@yahoo.com
The source code contains fonts from fntcol16.zip (c) by Joseph Gil avalable at : ftp://ftp.simtel.net/pub/simtelnet/msdos/screen/fntcol16.zip These fonts are public domain
The source code is based on information taken from :
- Kevin Lawton's vga card emulation for bochs/plex86
- Ralf Brown's interrupts list avalaible at http://www.cs.cmu.edu/afs/cs/user/ralf/pub/WWW/files.html
- Finn Thogersons' VGADOC4b available at http://home.worldonline.dk/~finth/
- Michael Abrash's Graphics Programming Black Book
- Francois Gervais' book "programmation des cartes graphiques cga-ega-vga" edited by sybex
- DOSEMU 1.0.1 source code for several tables values and formulas