joncampbell123/dosbox-x
1
0
Fork 0
mirror of https://github.com/joncampbell123/dosbox-x.git synced 2025-10-14 02:17:36 +08:00
Code Issues Packages Projects Releases Wiki Activity

suggest workaround for "Magic 12" demo issue.

Browse Source
This commit is contained in:
Jonathan Campbell
2015-02-03 16:57:42 -08:00
parent 1b8d87d964
commit 3ef6b60cf7
1 changed files with 12 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
BUGS/Magic 12 - Show.txt
View File

@@ -16,3 +16,15 @@ Memory corruption bugs:
first block in UMB, and DOSBox detects this as an "MCB list
corrupted" error.
Workaround:
You can avoid this crash/memory corruption by setting 'dos mem limit'
to a value less than 640 (such as 'dos mem limit=639') to mark off
the last 1KB of lower conventional memory as off-limits. If the demo
corrupts the bytes at segment 0x9FFF, it will have no effect and
DOSBox will no longer crash with "MCB list corrupted". It's possible
nobody ever caught the bug because most BIOSes by that point had
started taking the top 1KB under 640KB for the EBDA (extended BIOS
data area) and the corruption merely affected the unused trailing
end of it.