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stiggity
Account closed
Registered: Jul 2013
Posts: 5 |
c64 garbage collection, NEED HELP!!!
I came across a real nice "aftermarket" c64 garbage collection routine. I spent 2 hours on the source, and got it able to
compile in my assembler (64tass). but, all comments are in
German. Im writing a BBS program for the 64, and it runs and
works, but it will pause for 10/12/15 seconds here and there. And anyone not knowing its collecting garbage, may
drop carrier. I would like to intermingle this code, into my own project, but believe its a little above my skills level. If anyone is into c64 telecom, and thinks they could help me out, be my guest. I can describe, and explain how my memory is laid-out, with the BBS. So if you think your good, and believe this code _can_ be intermingled, I can fully credit you in docs, manual, website, and email support. Thanks. Id rather go back and forth via E-mail, rather than posting the source here. I'm safe! :)
-Thanks,
--Steve
stiggity99(@)Comcast.net |
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The Phantom
Registered: Jan 2004
Posts: 360 |
Sounds like the buffer is on. How to fix it, I've no clue ;)
Had a similar issue with Evil Term
Sorry can't really help further.. We never fixed the issue. |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
well if you want people to help, then you should post the code (or link to it)
however, it will need to copy the rom to ram because there is no other way to hook into it (there is no vector for the garbage collection). the only way to get around that would be to manually call the garbage collection every now and then (as said, at each prompt and/or after each message should do the trick - however, once you do that you can probably get away also by simply using fre(0) the same way) |
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TheRyk
Registered: Mar 2009
Posts: 2246 |
even
X=FRE(1)
will not solve the problem of an exponentially slowing down GC, the only difference is that you decide when GC takes place.
Quote:The best way to deal with garbage collection is to not make garbage strings in the first place
After a terrible experience when fixing a BASIC game
Murder V1.2 <- GC gets slower and slower while the game stays as crappy as it just is...
I'd even go further and say "Don't use strings at all", sounds weird but there are many other ways. |
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stiggity
Account closed
Registered: Jul 2013
Posts: 5 |
How do I 'properly' post my source??
-Stig |
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TheRyk
Registered: Mar 2009
Posts: 2246 |
Quote: How do I 'properly' post my source??
-Stig
use tags square bracket "[" 4 chars "code" square bracket "]" then of course your code and finally "[/" 4 chars "code" square bracket "]" |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
and if its more than a couple of lines, upload it somewhere and link to it. or use something like pastebin.com |
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AgentFriday
Account closed
Registered: May 2012
Posts: 4 |
TheRyk is right on the money. If you call the garbage collect routine twice in a row, it will take JUST as long the second time even though there's no work to do. So any thought of spreading out the pain by calling GC more often will only make things worse.
With the stock routine, your only hope is if you can call GC at a time when you know you can afford the penalty. If you can't go an entire session without doing a GC, your users will have to feel the pain.
:: THE GOOD NEWS ::
Pinacolada (Dragon's Eye BBS) knew about an improved garbage collection routine used by ImageBBS. A quick test in vice (DIM z$(9000):c$="A"+"":for i=1 to 9000: z$(i)=c$: next) shows that garbage-collecting 9000 1-length strings takes 106 minutes (!!!) with the ROM routine, but only 15.5 minutes with the replacement. (Thank you Warp Mode!)
Quick look at the algorithm shows it's collecting in batches of 128 strings at a time by doing an insertion sort in a separate table. Not sure if this reduces from O(n^2) to O(n log n), but it's something like that. Requires about 1.5 K of RAM (including space for the tables).
I did one more test to try to simulate your delays... With string array of size 500, but only 400 strings on the heap, ROM GC takes 16 seconds, ImageBBS code: 2 seconds.
I think this may be a good solution. |
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Oswald
Registered: Apr 2002
Posts: 5094 |
interesting problem, are there any good read materials about this, links, anyone?
thanks. |
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Count Zero
Registered: Jan 2003
Posts: 1932 |
And I thought Tao modded C*Base is the best there is anyhow nowadays? :) |
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AgentFriday
Account closed
Registered: May 2012
Posts: 4 |
Oswald: Specifically, are you interested in the topic of GC in general, how the stock GC works, or how string storage in general works? Or something else? |
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