Author Topic: PCW memory  (Read 1655 times)

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Offline mahlemiut

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PCW memory
« on: 08:08, 12 December 11 »
A few months ago, I sorted out an issue in MESS with booting PCW game disks (CPC paging mode has page locks on by default, the boot program just assumes they're active).  This fixed Matchday II, which is now perfectly playable in MESS, but Batman still won't load. 

It does now display the loading screen, but at one point, does a CALL &0000, and expects to return.  During loading, the first 16k bank is set to &34 (locks are still active, so should read and write bank 5 at &0000-&3fff)

Testing it in CP/M Box, the first byte of bank 5 is &c9 (RET), and this is there when the bank is first switched in, whereas in MESS, it is not.  Does anyone know how the RET gets there?  Using MESS' debugger to place a RET there before the CALL to &0000 results in the game starting up and running perfectly.

I could simply place the RET in bank 5 on a system reset in MESS to fix it, but I would like to how it is supposed to work, so that if there is a proper way to get that RET (or whatever is supposed to be there) to be put there, that can be done.
- Barry Rodewald
Amstrad CPC, Sharp X68000, Neo Geo Pocket, and Neo Geo AES system leader at HARP
http://www.homeactionreplay.org/

Offline RockRiver

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Re: PCW memory
« Reply #1 on: 14:03, 12 December 11 »
I think you would ask to Habi -CP/Mbox creator- which is a PCW encyclopaedia with legs...  8)
I don't see him in these forums but you can write here: in english is ok too: http://www.amstrad.es/forum/viewforum.php?f=35
Then if I understand: in this matter CP/Mbox works OK; MESS doesn't and what about JOYCE -emu by John Elliot- ?

Thanks to Habi for such a great emu http://www.habisoft.com/pcw/index_uk.htm and John Elliot for his work preservating PCW knowledge during decades.

Offline mahlemiut

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Re: PCW memory
« Reply #2 on: 23:25, 12 December 11 »
Yeah, it's been a while, but I remember it working in Joyce also.  Had issues building later versions of it, but have used an old DOS version via DOSbox before.  More recent versions lack debugging features, if I remember right, also...
- Barry Rodewald
Amstrad CPC, Sharp X68000, Neo Geo Pocket, and Neo Geo AES system leader at HARP
http://www.homeactionreplay.org/