VGA registers headache - Programmers Heaven

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VGA registers headache

WeqlWeql Posts: 26Member
I originally posted this message in the x86 assembler forums of this same website, but no one has replied yet, or just no one cares. I figure that if any demosceners are here, they'll be more knowledgable about my problem and perhaps willing to help. I know it's bad practice to post a message on two boards, but I realize that this message is probably better suited to this particular board. Please read onward.

Hello. After having some fun with VGA mode 13h I googled about video modes and found a program called TWEAK, which at the time sounded like the holy grail of VGA register programming. I spent last night and this morning coding in asm a small .256 file-parser, so I could just 'incbin' those files where I wanted them and have access to new video modes (lucky for me, the format is very simple...). The point is, that although now I have it 'implemented', it simply does not work. I checked everything numerous times and all seems to be in order, but the screen does not change to the mode I want (256x256:256). These are the sources thus far (very small...):

http://weql.tripod.com/main.txt (the main file, includes a pixel-test)
http://weql.tripod.com/vga.txt (the video-mode file, sets modes ...)
http://weql.tripod.com/geometry.txt (for curiousity's sake ...)
http://weql.tripod.com/256X256C.256 (TWEAK's 256x256 chained mode ...)

Finally, my build.bat:
@echo off
tools
asmw -fobj geometry.asm -ogeometry.obj
tools
asmw -fobj vga.asm -ovga.obj
tools
asmw -fobj main.asm -omain.obj
toolsalink -entry @main main.obj vga.obj geometry.obj -o embrace.exe -oEXE
del geometry.obj
del vga.obj
del main.obj

I would be very grateful if someone were to look over what I've done, or point me in the right direction, or even just give me some tips on VGA register debugging. Thanks in advance.

Edmund 'weql' Huber

Addendum: I've heard from someone that 256x256-chained is an odd video mode, but I tried the program with TWEAK's other .256 files and none seemed to work. Also, I rechecked many more times from TWEAK's sources and nothing has helped ...


Edmund 'weql' Huber
Your friendly Argentine.
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