Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!rex!rouge!ralph!elgamy!rgjami!rgj From: rgj@rgjami.raidernet.com (Randy Jouett) Newsgroups: comp.sys.amiga.misc Subject: Re: Euro"Euro" demos: why do'nt they work? Message-ID: Date: 11 Jun 91 01:24:10 GMT References: <3999@beguine.UUCP> Reply-To: rgj@elgamy.raidernet.com Organization: PetroSoft, Inc. Lines: 37 In article <3999@beguine.UUCP> John.Carver@bbs.acs.unc.edu (John Carver) writes: >I have recently obtained some of the Euro demos on ab20. However, none >of them seem to work. > >Here's the situation: I can run about 50% of them on my friend's A1000. >I have a 2000 with an 68030 board, which seems to break ALL of the Euro >demos. However, I know the board is OK becuase I can run any other >software at all: applications, games, traditional demos, utilities, etc. >Only the Euro demos don't work right. > >These things seem to be clever enough that it looks like the authors >could make them run on other machines. > Isn't this a great question!! Hopefully, this will be a great answer :). Anywho, after disassembling quite a few of these programs with ReSource, I've come to the conclusion that these people simply don't read the RKM's :/. Unfortunately, a lot of these programs are using the upper 8 bits of an address for flags, and this will cause an instant smashola on the 030. If that isn't bad enough, they are also using self-modifing code, don't dynamically allocate memory (Read: write directly to an absolute address without use of Allocate(), AllocMem(), or AllocAbs()!!!), don't do an OwnBlitter() & WaitBlit() when accessing the Blitter directly, install their own interrupt routines in the Trap vectors, and grab any and all system resources without even considering that they are using a multi-tasking OS! Oh, yeah -- almost forgot sumfin! :). They also jump directly to ROM code! NAK! I guess your friend should consider himself lucky. After all, he can at least view some of the demos :). Randy -- Randy Jouett BIX: rjouett Amateur Radio: KB5YL rgj@elgamy.RAIDERNET.COM uunet!mjbtn!raider!elgamy!rgj