English Amiga Board


Go Back   English Amiga Board > Support > support.Games

 
 
Thread Tools
Old 31 October 2010, 06:22   #1
MethodGit
Junior Member
MethodGit's Avatar
 
Join Date: Dec 2002
Location: The Streets
Age: 35
Posts: 2,731
Problematic Holiday Lemmings 94 demo disk

I recently discovered one of the Holiday Lemmings 94 disks in TOSEC to be a demo disk rather than the full version. Interested, I wanted to play through it for fun, but it seems no matter what quickstart config I use, the game will freeze on a black screen (with the lemming hand cursor still interactive) after you click the mouse button on the level info so you can start the level.

I know for a fact that the demo available on one of The One's coverdisks from January 1995 works brilliantly, so I attempted to do file comparisons. Only the executable differed from the two versions, and the TO version was crunched, so I had to unpack it first.

Upon unpacking, TO's demo exe weighed in at 142948 bytes, compared to the TOSEC exe's 142944 bytes. Hex-wise, the files aren't dramatically different, with only the sporadic byte changes incurred no doubt as a result of the packing process the TO exe originally went through, though at some point (mainly at the start of the "end of demo" text) the files will veer off one another by just one character, and it stops becoming easy to find major hex changes. I attempted to get around this by editing the TO exe bit-by-bit until the files were more aligned with one another, but despite all this I can't find any significant changes aside from the aforementioned sporadic byte modifications, and I still can't work out why one exe fails and the other performs marvellously.

So, if anyone wants to look into it further - by whatever means necessary - then find "Lemmings - Holiday Lemmings 1994 (1994)(Psygnosis)[a].7z" on the EAB file server, and grab the TO version from the above link, and frolic away!

(Of course, if navigating the server is too much bother, I *could* zone up the two versions if there are enough requests. )
MethodGit is offline  
Old 31 October 2010, 09:40   #2
mai
Moderator
 
Join Date: Feb 2008
Location: GER
Posts: 4,878
...at least A1200 works fine here.
mai is offline  
Old 31 October 2010, 09:47   #3
TCD
Registered User

TCD's Avatar
 
Join Date: Sep 2006
Location: Germany
Age: 41
Posts: 24,012
Quote:
Originally Posted by mai View Post
...at least A1200 works fine here.
Here as well. A500 & A600 doesn't though.
TCD is offline  
Old 31 October 2010, 15:46   #4
MethodGit
Junior Member
MethodGit's Avatar
 
Join Date: Dec 2002
Location: The Streets
Age: 35
Posts: 2,731
Strange. An AGA-only demo? That doesn't sound right somehow. Lemme check anyway.
MethodGit is offline  
Old 31 October 2010, 17:06   #5
MethodGit
Junior Member
MethodGit's Avatar
 
Join Date: Dec 2002
Location: The Streets
Age: 35
Posts: 2,731
Okay, what it seems to boil down to is processor. The demo will not work correctly on anything below a 68020.

On a 68000 the "freeze on black screen" bug occurs. On a 68010 it won't even get past the initial opening text in the CLI window. On all other processors - including a 68060 - it'll work as intended. Even with JIT and CPU speed cranked all the way up!

This surely makes for one fudged up executable if it's been compiled to fail on the earliest Amiga models. Maybe someone with more technical wizardy could explain what went wrong somewhere in the code? Since the 68020 is faster than the 68000, maybe it's a display speed issue.
MethodGit is offline  
Old 31 October 2010, 17:12   #6
TCD
Registered User

TCD's Avatar
 
Join Date: Sep 2006
Location: Germany
Age: 41
Posts: 24,012
Quote:
Originally Posted by MethodGit View Post
Maybe someone with more technical wizardy could explain what went wrong somewhere in the code?
Who really cares (except you of course ) about it anyway? A working non-demo version exists, so I wonder what the actual use of such an investigation would be.
TCD is offline  
Old 31 October 2010, 18:24   #7
MethodGit
Junior Member
MethodGit's Avatar
 
Join Date: Dec 2002
Location: The Streets
Age: 35
Posts: 2,731
Because something obviously had to go wrong in order for a program to lose all 68000/010 compatibility when a similar demo works on all Amigas? People need to know these things in case you get more threads of this calibre again in future.
MethodGit is offline  
Old 31 October 2010, 18:33   #8
mai
Moderator
 
Join Date: Feb 2008
Location: GER
Posts: 4,878
...thanks for info, [68020] added.
mai is offline  
Old 31 October 2010, 18:54   #9
TCD
Registered User

TCD's Avatar
 
Join Date: Sep 2006
Location: Germany
Age: 41
Posts: 24,012
Quote:
Originally Posted by MethodGit View Post
People need to know these things in case you get more threads of this calibre again in future.
Fingers crossed that it doesn't happen...
TCD is offline  
Old 01 November 2010, 13:06   #10
MethodGit
Junior Member
MethodGit's Avatar
 
Join Date: Dec 2002
Location: The Streets
Age: 35
Posts: 2,731
I should probably have asked that if anyone happens to own a real 68000 Amiga, then could they test the disk on one to confirm that the problem occurs under real hardware also? Thanks.
MethodGit is offline  
Old 01 November 2010, 14:04   #11
fitzsteve
Professional slacker!
fitzsteve's Avatar
 
Join Date: Jul 2009
Location: Kent, UK
Age: 39
Posts: 6,353
Send a message via MSN to fitzsteve
Quote:
Originally Posted by MethodGit View Post
I should probably have asked that if anyone happens to own a real 68000 Amiga, then could they test the disk on one to confirm that the problem occurs under real hardware also? Thanks.

I can do that later, can you zone the ADF so I'm using the same one?

Give me somthing to do instead of boring housework

My A600 has 68k / 020 and 1.3 / 3.1 roms so it should be good platform to test all configurations for you on real hardware
fitzsteve is offline  
Old 01 November 2010, 16:04   #12
MethodGit
Junior Member
MethodGit's Avatar
 
Join Date: Dec 2002
Location: The Streets
Age: 35
Posts: 2,731
Just zoned it for you, buddy.

Even put it in a zip for you in case Amigas still have trouble with the 7z format.
MethodGit is offline  
Old 01 November 2010, 16:26   #13
Mad-Matt
Longplayer

Mad-Matt's Avatar
 
Join Date: Jan 2005
Location: Lincoln / UK
Age: 40
Posts: 1,596
Send a message via ICQ to Mad-Matt Send a message via MSN to Mad-Matt
This seems to work ok in uae 68000 with ce and mc dissabled.
Mad-Matt is offline  
Old 01 November 2010, 16:29   #14
Toni Wilen
WinUAE developer
 
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 44
Posts: 23,132
I can't see any loading problems. Works until level is supposed to start and then it crashes because it writes longs to odd address (need 68020+)
Toni Wilen is offline  
Old 01 November 2010, 18:01   #15
MethodGit
Junior Member
MethodGit's Avatar
 
Join Date: Dec 2002
Location: The Streets
Age: 35
Posts: 2,731
Quote:
Originally Posted by Mad-Matt View Post
This seems to work ok in uae 68000 with ce and mc dissabled.
Oooooh so it's an issue with the More Compatible tag? I did test with CE both on and off and got the freeze issue.
MethodGit is offline  
Old 01 November 2010, 18:49   #16
MethodGit
Junior Member
MethodGit's Avatar
 
Join Date: Dec 2002
Location: The Streets
Age: 35
Posts: 2,731
Okay, so here are my findings based on certain settings...

68000, Cycle Exact on (Quickstart A500 default) = freezes on black screen.
68000, Cycle Exact off, More Compatible on = freezes on black screen.
68000, Cycle Exact off, More Compatible off = works!
68010, Cycle Exact on, More Compatible on/off (doesn't really matter) = hangs on opening text CLI screen.
68010, Cycle Exact off, More Compatible on = works!
68010, Cycle Exact off, More Compatible off = works!

Say Toni, would you be able to explain why MC would be the one conflicting with the game's code and its performance on certain processors (like, how does it work and what not)? Kinda ironic given its name and all.
MethodGit is offline  
Old 01 November 2010, 19:03   #17
Toni Wilen
WinUAE developer
 
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 44
Posts: 23,132
Black screen is CORRECT behavior on a 68000! It requires 68020 or "non compatible 68000".

EDIT: Compatible = includes address error exception checks (more work to do), non compatible = ignores address errors = faster.

Last edited by Toni Wilen; 01 November 2010 at 19:11.
Toni Wilen is offline  
Old 01 November 2010, 19:27   #18
MethodGit
Junior Member
MethodGit's Avatar
 
Join Date: Dec 2002
Location: The Streets
Age: 35
Posts: 2,731
Quote:
Originally Posted by Toni Wilen View Post
Black screen is CORRECT behavior on a 68000! It requires 68020 or "non compatible 68000".
Then I guess it's just a pretty borked executable. Like I said, the version distributed by The One has no such problems on a 68000.

Quote:
EDIT: Compatible = includes address error exception checks (more work to do), non compatible = ignores address errors = faster.
Thanks for the explanation, Mr Wilen.
MethodGit is offline  
Old 01 November 2010, 19:48   #19
fitzsteve
Professional slacker!
fitzsteve's Avatar
 
Join Date: Jul 2009
Location: Kent, UK
Age: 39
Posts: 6,353
Send a message via MSN to fitzsteve
Hey!

I guess you guys have it sussed, but anyway I tried on my A600 and in 68k mode it black screens at the start of the level. (Tried both 1.3 and 3.1 Rom)

In 020 mode it worked just fine

Steve.
fitzsteve is offline  
Old 08 November 2010, 03:56   #20
Eclipse
Turpentine
Eclipse's Avatar
 
Join Date: Oct 2007
Location: Kent, United Kingdom
Posts: 743
There was probably meant to be an AGA version at some point. I'm guessing things might have got mixed up between an AGA and standard demo.
Eclipse is offline  
 


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Lemmings Holiday demo and hidden levels! Psygore project.WHDLoad 21 27 December 2013 09:01
Oh no! more lemmings Xmas Demo missing? jpmaverick HOL contributions 8 30 June 2013 13:44
Problem with Holiday Lemmings 1993 / WHDLoad edd_jedi support.Games 11 13 April 2010 14:40
Lemmings Promo Demo mai request.Old Rare Games 23 07 May 2008 03:20
Lemmings AF Demo - can't complete last level! MethodGit support.Games 32 12 April 2007 18:30

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +2. The time now is 01:21.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Page generated in 0.09724 seconds with 13 queries