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Majikeyric
Registered: Sep 2002
Posts: 83 |
How does linecrunch work ?
Hi everybody !!!!
Can someone explain or point me to a web site where I could find information about linecrunch ???
I think it allows to scroll bitmaps but I don't know how ???
thanks. |
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tecM0
Registered: Jan 2002
Posts: 41 |
another great VIC_infopage:
http://www.minet.uni-jena.de/~andreasg/c64/vic_artikel/vic_arti..
point 3.1.14 explains linecrunch...a little bit...
tecM0/+H |
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Majikeyric
Registered: Sep 2002
Posts: 83 |
Thanks everybody !!! |
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
be aware that linecrunching causes trouble on some machines. when doing linecrunching on these some bits in memory will be randomly cleared in most cases. on my flat c128 linecrunching only works after testing it several times and turning the machine off and on again between each test.... but IF it runs, all linecrunching demos and games do run.
however this is not a c128 problem like some people believe. it's a problem of VIC revisions. machines with 8562/8565 VICs don't have this problem (C64C, C64G and C128DCR). problems only occur on the flat c128, the old c128d and old c64's. i even have seen one c64 which wasn't able to do plain FLI. |
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Ninja
Registered: Jan 2002
Posts: 418 |
a c64 that cannot do FLI? Wooow, wanna have, ULTRA-RARE, big bucks on ebay!! ;)) |
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algorithm
Registered: May 2002
Posts: 707 |
It might be a power supply problem. I know it sounds very unusual.
All demo's and games which shift the screen horizontally using a graphic trick (placing specific byte combinations in $d011 followed by a self modified delay and yet another value in $d011) would seem to randomly crash the entire system.
During my C64 days (A very long time ago) I had created a small utility which would test this and give a report on the amount of bytes that were corrupted. If it did this or crashed (Due to the very possible corruption of program data) I would find that switching the system off and on would sometime solve the problem.
Mind you, this would sometimes have to be done 7 or 8 times.
After a while, I got a new power supply unit and guess what. This problem never happened again!!
I had previously read somewhere that the the linecrunch routine causes the VICII chip to draw in more power and a faulty or weak powersupply would cause memory corruption. Who knows...
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Shadow
Account closed
Registered: Apr 2002
Posts: 355 |
I have this problem with my C64 (new model, not the breadbox).
Many demos that have graphic scrolling lock up after just a few seconds. Never had any issues with games though, and FLI etc. works perfectly. |
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
"new model" doesn't mean anything except for the casing. it most likely still has an old board inside with 65xx ic's. |
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raven
Account closed
Registered: Jan 2002
Posts: 137 |
well none of my machines have this problem (old,new,flat 128, 128D) but i've seen it happen on one machine (c64c) at X2001..
Thats one very interesting problem |
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Cybernator
Account closed
Registered: Jun 2002
Posts: 154 |
I've tested all my C64s, and the only thing that doesn't work on old ones, is $DE00 programs.
One of my new C64s works fine, except with Insomnia (of course there must be something else, but this is what I have found so far). The computer simply locks up at the beginning. I suspect that CIA2 is blown. One old C64, gives me a message saying something like: "Disk drive not present", although it works with other programs as well.
@Raven: What does your code do at the beginning? (Before the screen fader). I guess it installs the fastloader into the 1541s memory. So most probably it's CIA2. But strange thing is that everything else I've tried so far, works perfect.
@Graham: Btw, on your site I've read that the 8500 is 6510 with different pin layout. I haven't tried to swap the processors, but I've seen an old C64 with 8500 processor (it didn't seemed to be resoldered at home). It worked normally. Are you sure it's the pin layout? I assumed it was the voltage difference here.
Btw, anyone knows the difference between 6526-A (used in new C64s), and 6526 (used in old C64s)? |
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Stryyker
Registered: Dec 2001
Posts: 469 |
I think the A means 2MHz mode available too. |
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