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1st Canadian Shareware Disc
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1st_Canadian_Shareware_Disc_1991.ISO
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svga256m
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svga256.doc
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1990-11-05
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2KB
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40 lines
Hey all. I found this .BGI driver on a local board, it supported 3 graphmodes;
1: 640x400x256 (5Ch)
2: 640x480x256 (5Dh)
3: 800x600x256 (5Eh)
So I patched it, now the graphmodes are as follows:
1: 1024x768x256 (62h)
2: 640x480x256 (5Dh)
3: 800x600x256 (5Eh)
I've included slightly patched tp55 source to borlands vga256 demo, so y'all
can check it out. The demo is set for graphmode 1 (1024x768x256).
If any of you are interested in patching this for other video modes,
it's not too hard. You need pctools or some other hex editor. First,
look for the mode numbers (hex)- you should find 62,5D and 5E near the
beginning of the file, all separated by several 00s. Change the mode
number that you want to change. Then take the original resoloution (for
the mode number before you just changed it), subtract 1 from each
dimension (so if you are changing graphmode 2, you have just replaced
the 5D with whatever mode # you want, in hex, then you take the 640 & 480,
subtract 1, & get 639 & 479). Now convert them to hex. 639=027Fh 479=01DFh.
Now reverse the low & high bytes, so you have 7F02h & DF01h. Look for the
first one of these in the file (towards the end). You will see the first
one, then the second one, then the first one repeated (7F 02 DF 01 7F 02).
Change these to the correct numbers for your mode. Then just look for the
ASCII identifier for your mode (in this case "SuperVGA 640x480x256") and
put the correct numbers in for your mode; keep the length of the string the
same, if you change it you may corrupt the code (that's why mode 1 says
"SuperVGA1024x768x256" and the others have a space after the "SuperVGA").
I monitor the RIME turbo pascal conference, if you want to contact
me. When I got the original .BGI driver (before I patched it), it was
in a zip with a little readme which said nothing about it being other
than public domain, so I hope I'm not violating anyone's deal by uploading
this. I seek no remuneration personally. Have fun. - David Lipper
NOTE: don't change the name of the .BGI file or it won't work. I tried to
change the file ID inside the .BGI so I could change the name, but it didn't
work & I didn't pursue it. I someone figures this out, please send me some
mail & let me know how. Also, please don't rename the zipfile svga256.zip
since that was the name of the unpatched version. I added an M to the
filename since you need 1 Meg of video memory to use mode 1. Thanks.