wbcbz7/s3vbefix

PC/MSDOS TSR fix for S3 VESA video BIOS

s3vbefix's Issues

VBETEST crash when /M[x] key is used

first issue :)

When using /M[x] key (override memory size), where x is NOT equal actual memory size in 64kb units, VBETEST.EXE from SciTech Display Doctor is unable to finish videomode test. While attempting to scroll virtual screen it crashes with this message:

CauseWay DOS Extender v3.25 Copyright 1992-96 Michael Devore.
All rights reserved.

Exception: 0E, Error code: 0006

EAX=00000000 EBX=00000000 ECX=0007FC00 EDX=00000000 ESI=004640AC
EDI=FF600000 EBP=00463F58 ESP=00463F48 EIP=0043D1AB EFL=00213214

CS=01A7-FFBCA000 DS=01AF-FFBCA000 ES=01AF-FFBCA000
FS=0000-xxxxxxxx GS=01B7-xxxxxxxx SS=01AF-FFBCA000

CR0=00000000 CR2=00000000 CR3=00000000 TR=0000

Info flags=00008042

Writing CW.ERR file....

CauseWay error 09 : Unrecoverable exception. Program terminated.

I think it crashes because VESA function 0x4F06 returns incorrect number of available scan lines in DX register, so we need to patch or rewrite this function.

p.s. freaking DOS extenders :)

S3 virge-virge dx frequency setting & brightness bug

Hello i'm sorry to contact you in such uncommon way but it was the only one I could find.

I'm trying to identify the offsets in the bios of s3 cards (virge, virge dx and trio 64v+) which controls the memory and core frequency (to my knowledge they are syncro).

According to MCLK there are 3 settings to set the frequency clock, despite of that I can't find the right offsets in the bios:
[IMG]https://i.imgur.com/xF8N38f.png[/IMG]

I also found the trio64v+ full documentation (http://vgamuseum.info/index.php/cards/item/download/516_2bbbf61d0bbde9fe22086633b5908851) section 9-1 explain how the frequency is selected (pdf pages 74-75-76)

In attachment there is my bios collection, it contains bios from my virge dx cards, one with 70 mhz with the infamous bright bug (https://www.vogons.org/viewtopic.php?f=63&t=43472&start=80), the second is the bios version at 66 mhz coming from another card, the others 2 are bios I donwloaded and according to vogoners the most recent versions which have 50 mhz for memory and core).

https://drive.google.com/open?id=1agGrV13styN2YDHFP2hlAG3LW2S7CjEG

Thank you in advance for any help.