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6R6
Registered: Feb 2002
Posts: 244 |
Disabling AR freeze button
Is it possible to disable the Action
Replay freeze function 100% ?
In that case, please enlighten me... :)
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... 83 posts hidden. Click here to view all posts....
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TNT
Account closed
Registered: Oct 2004
Posts: 189 |
Doesn't RR ROM write $de01 during boot?
(I use the freeze button for disk swapping in MMC64 disk image mounter, that works because RR ROM doesn't get run before the plugin.) |
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Oswald
Registered: Apr 2002
Posts: 5020 |
Quote: Somebody write a short article on the mechanisms of common c64 freezers and put up on http://codebase64.org :)
I second that. |
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AlexC
Registered: Jan 2008
Posts: 293 |
Quote: I second that.
I'll have a short write up on different bugs and features not mentioned in codebase. I'll try to clean it up during weekend and post it here for review first. I need to recheck $de01 access by different roms too. |
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Frantic
Registered: Mar 2003
Posts: 1627 |
great! |
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AlexC
Registered: Jan 2008
Posts: 293 |
Quote: Doesn't RR ROM write $de01 during boot?
(I use the freeze button for disk swapping in MMC64 disk image mounter, that works because RR ROM doesn't get run before the plugin.)
You are right. I've took a peek at 3.8 and at $817F there is the following code:
LDA #$40
STA $DE01
which enables REU comaptybility and Freeze button as well. So my code will not work if run after RR setup however it stills hangs the system so one can say it is disabling freeze option ;) |
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titan_ae
Account closed
Registered: Jun 2002
Posts: 46 |
best "protection" against freezing i saw in an german adventure game called "mit jeans und hellebarde" from markt und technik verlag.it checked he exp. port, if something was conected there, game didnt start and ofcourse freeze button didnt werk.
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chatGPZ
Registered: Dec 2001
Posts: 11123 |
uhm but...both FC3 and AR5 can switch off themselves completely (and will be switched on again when you press freeze) so its pretty much impossible to detect them programatically. |
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AlexC
Registered: Jan 2008
Posts: 293 |
Quote: uhm but...both FC3 and AR5 can switch off themselves completely (and will be switched on again when you press freeze) so its pretty much impossible to detect them programatically.
Most of those methods will also fail against Trilogic Expert. It can also be switched to off and than re-enabled after PC register passes protection code. In some games you will also lack time in IRQ to recheck again.
Some older version - if memory serves me well - of AR were leaving certain values on stack during freeze.
In case of AR you can also enable it's memory and store your code there which will get overwritten due to freeze.
IMHO the best option is to use VIC, SID and timer registers to detect freeze has been triggered. Also synchronization issues can screw up code execution so that return after freeze will not be possible. Those methods are also very flexible as they work against different carts not just AR.
You can also play with disk drive memory in order to detect any writes (but today it's real use is rather limited unless you are afraid of piracy).
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sailor
Registered: Jan 2002
Posts: 90 |
Hello.
Started a topic about cart-detection for some time ago, there was some mention about freeze-detection too. If anyone is interrested, check this one: How to detect a cartridge..?
Regards:
Jani
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Necronomfive
Account closed
Registered: Dec 2004
Posts: 20 |
It's impossible to detect a AR/RR Cartridge once the freezer software has disabled it. The only way to prevent freezing is fire an NMI and not acknowledging it. On RR/MMC Replay, nothing will happen in this case when the Freeze button is pushed. On AR, I am pretty sure that the system will be fucked up once freeze is pressed, because the cartridge will map in Ultimax mode without the CPU jumping to the NMI vectors. |
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