Windows 2.x stub display driver - work in progress
This is a seriously cut-down version of Microsoft Windows 2.1 DDK driver for EGAHIBW. It misses most of the GDI parts yet it "works" in a sense that it is possible to load the system with this driver, and the system will be fully* operational except for the display.
Windows 1.x-3.x display drivers have a large chunk of Windows GDI code inside. Microsoft thought it was a good idea, because driver developers could leverage hardware acceleration this way. In reality, it turned out to be a terrible idea. All the display drivers had to be forks of Microsoft reference implementation drivers, and it has lots of internal references.
I have tried to create a "stub" driver implementing the basic functions Windows kernel expected the display driver to have a few times, but somehow it always ended up being a driver that makes GDI crash on start. And don't get me wrong, I love debugging 16-bit realmode code. But it is super yucky to do when you have no sources for it.
And, uh, your debugger is symdeb.
So, it is proving to be much more productive to cut big chunks of the driver off and see what breaks, and fix it.
The end result, hopefully, would be a very lean driver that looks a lot like the driver from MS DDK reference, but with stubs that would allow a custom implementation for major chunks of the driver.
That would help me to do two things:
- Understand how exactly Windows 2.x video drivers work,
- Make a custom Windows 2.x video driver for a computer that I have,
- Make a custom Windows 3.x video driver for a computer that I have
Ogeh, stack protector!!
- Get a DOS 3.3+ computer/virtual machine
- Get Windows 2.0 or Windows 2.1 DDK and MASM 4.0+
- Install tools from Windows DDK into %PATH%
- Prepare debuggable Windows 2.x copy using folder WINBOOT from your DDK set
- Go to the folder of win2stub_dd (you'd have to rename it to 8.3 format maybe)
make makefile. This should compile a bunch of*.objfiles, and link them into a file egahibw.drv. Res file is already pre-compiled- Copy egahibw.drv into your WINBOOT folder
- Run
symdev kernel.exefrom your WINBOOT folder. - Press
gandEnterto start the system. Press Alt+F4 to initiate "This will end your windows sessions" Dialogue. Press "Enter" to exit.
The default IBM PC keyboard driver has a special check for text/graphics mode, and turns itself out when BIOS reports its in the text mode. There's a ever-so-slightly patched keyboard driver in KEYBOARD folder that works with this video driver.
There's still a lot of code cleanup needed.