Marius Posted February 17, 2014 Share Posted February 17, 2014 Hi Is there someone here who is able to convert the following games to a cart. I would love to be able to run these games on a 64K computer, in cart form. With THE!CART it would be awesome to be able to play these games on a stock 64K atari. 1) Johny's Trouble 2) Cropky 3) The Brundles Unfortunately these games do not run from an emulated ATR-from-cart-boot-OSpatch. I was able to create a SIC cart with XDOS 2.4 on it, and put Cropky on a ramdisk bootable from D1: ... but indeed: that needs a memory expansion. Quote Link to comment Share on other sites More sharing options...
Rybags Posted February 17, 2014 Share Posted February 17, 2014 Some games just won't work from cartridge without extensive hacking. Cropky - from memory that one is a compiled Basic game on a double-density image and probably switches the OS ROM back in - the basis of making an ATR able to load from a cart is copying the OS to Ram and putting a patch in such that disk input can be simulated by dragging the relevant "sectors" in off the ROM. Brundles - chances are it uses Ram under the OS, if it's the case then lots of effort required to get onto ROM. Quote Link to comment Share on other sites More sharing options...
Marius Posted February 17, 2014 Author Share Posted February 17, 2014 I know, but my question is: Is there someone able to HACK these games into real cart games. I created myself a cropky version that works from SIC! Cart. But then I still need 320K. Quote Link to comment Share on other sites More sharing options...
Rybags Posted February 17, 2014 Share Posted February 17, 2014 Closer look - all 3 of these games hit PORTB, all 3 have program and/or data under the OS ROM. Getting to work from a cart - probably possible but not a trivial job. Quote Link to comment Share on other sites More sharing options...
+JAC! Posted February 17, 2014 Share Posted February 17, 2014 (edited) >but indeed: that needs a memory expansion THE!CART has 128K RAM built in (used as buffer by the Flasher), so "all you need" is somebody to write a RAM disk driver. At least for those things that can be solved using Dx:. As for the others I have an Idea how to make ATRs run from carts in general without using the RAM under the OS (but it's still secret, nothing that was done before and way too far ahead on the project list :-). Edited February 17, 2014 by JAC! 1 Quote Link to comment Share on other sites More sharing options...
HiassofT Posted February 17, 2014 Share Posted February 17, 2014 >but indeed: that needs a memory expansion THE!CART has 128K RAM built in 512k :-) As for the others I have an Idea how to make ATRs run from carts in general without using the RAM under the OS (but it's still secret, nothing that was done before and way too far ahead on the project list :-).For DOS based stuff that doesn't use SIOV directly (except for the DOS) we might have a possibility which doesn't require writing a lot of code: MyPicoDos in DiskCart/DiskWriter (still need to find time to finish The!Cart version) uses a small RAM-based SIO stub which calls the actual cart-SIO code in the cart. The stub basically just does some setup stuff, calls the cart code and then copies the "SIO data" from the cart to RAM. So the memory footprint of the stub is quite small. The flasher in The!Cart, when started directly from The!Cart, installs MyDOS in memory and changes the SIO calls of MyDos to point to the highspeed code in the flasher - so accessing files on Dx: uses highspeed SIO without requiring a patched OS in RAM. If we combine both things - find a small RAM area for the SIO stub and point the MyDOS (or any other DOSes) SIO calls to the cart SIO stub - we should quite easily get the possibility to use read-only disk images from the cart (just install the patched DOS in the RAM and let the remaining boot be handled by DOS). I haven't looked at the images yet, do they use a DOS? If no we'll have to wait for JAC's idea so long, Hias Quote Link to comment Share on other sites More sharing options...
Marius Posted February 18, 2014 Author Share Posted February 18, 2014 That sounds all very interesting. I think Cropky is a dos disk, since I can run it from a ramdisk on D1: too, so big chance that one will work. The Johny's Trouble is probably a packed data block, that is loaded sector-by-sector from disk using a custom loader. And as soon as the game is running screen data is loaded from disk. No idea how that works. The Brundles is a different story. That is a real complicated disk. Fooling around with IRQ's (which are switch off a lot) and it is also a multi sided disk. Quote Link to comment Share on other sites More sharing options...
Rybags Posted February 18, 2014 Share Posted February 18, 2014 Yes, I think Cropky would be the easiest of the lot... a virtual disk driver that uses the cart might be sufficient. The other 2... I got real doubts. Although with things that call SIOV there could always be the option to hunt out those instances and call the stub. Then just a case of finding somewhere in RAM to hold the block of required code. So long as there's no encryption of the program on the disk or other funny business it might be a reasonably easy job. Quote Link to comment Share on other sites More sharing options...
+JAC! Posted February 18, 2014 Share Posted February 18, 2014 (edited) Aaargh, Rybags revealt it, but I also have an idea for the encrypted part :-) Edited February 18, 2014 by JAC! Quote Link to comment Share on other sites More sharing options...
Wrathchild Posted February 18, 2014 Share Posted February 18, 2014 There are other considerations too, programs using the cart banking area for their own use - especially DLIs, VBIs and screen memory - pose a problem because they are not there when accessing data from the cartridge and unless handled appropriately then normally cause a crash or at minimum affects to the display during loading. Quote Link to comment Share on other sites More sharing options...
+JAC! Posted February 20, 2014 Share Posted February 20, 2014 (edited) The first incarnation of my ATR loader has just loaded "The Brundles" which uses the RAM under the OS during loading from The!Cart. To be tested an real HW, but already lots of interesting learnings from this (like "double density will be hell", "you forgot the update GINTLK..." etc.). It also takes into acount what Wrathchild worte. Interestingly the overall loading speed does not seem the become worse when I restrict the loading to the offscreen/blank area.Maybe also a bug in my routine, we'll see :-) Edited February 20, 2014 by JAC! 3 Quote Link to comment Share on other sites More sharing options...
Marius Posted February 20, 2014 Author Share Posted February 20, 2014 In that case you might find a solution for multi side disks too? Or am I asking too much now? It is getting very interesting yes!!!! Quote Link to comment Share on other sites More sharing options...
+JAC! Posted February 20, 2014 Share Posted February 20, 2014 (edited) Once you have the exit in the SIO, multi-(sided) disks are not a conceptual issue, but only a question of available space & handling (check keys in SIO routine or hook up the keyboard interrupt). MegaCart Studio has a already working & nice implementation for multi disks were you can press special keys to select the disks. But since it relies on patching the OS, it cannot work with things that use that area. Edited February 20, 2014 by JAC! Quote Link to comment Share on other sites More sharing options...
Rybags Posted February 21, 2014 Share Posted February 21, 2014 On a game by game basis, multi disk could be handled (but lots of work) - chances are many games just maintain a single-byte variable describing which disk is needed. If a multi disk game is adapted as such to cart, then in parallel it could also be adapted to large ATR image... the holy grail there would be the Alternate Reality games being able to run off a single image. Quote Link to comment Share on other sites More sharing options...
+JAC! Posted February 21, 2014 Share Posted February 21, 2014 >the holy grail there would be the Alternate Reality games being able to run off a single image. I know this one http://www.giors.com/video-games/downloadarwrappernow and It's actually much more than putting it on a single image/ROM could achieve. So not really the kind of grail I'd be after :-) Quote Link to comment Share on other sites More sharing options...
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