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Of wherever the cartridge rom starts until the end of the segment. The code is easy to find, just do a 'wpset e0000,1,r' in the debugger.

If you pull up page 461 like he said, there's complete commented source for the BIOS routine that does it. The header comment says "This routine checks optional ROM modules (checksum for modules from C0000-D0000), CRC check for cartridges (D0000-F0000)".

Got demon attack working locally:
- The first 8kb is mirrored four times at e0000, e2000, e4000, and e6000
- The last 8kb is mirrored four times at e8000, ea000, ec000, and ee000

And the same trick also applies to micro surgeon. It makes sense from a hardware point of view, just hook up the address lines a bit differently to the 16kb rom and you get that behaviour.

Anyway, enjoy the fix!

Nice!

Wow, very nice.

Is the BASIC cartridge working too?

PS: I doesn´t have the last revision compiled.

Last revision compiled and it works.

Microsurgeon



Demon Attack

DOSBox is not able to load directly the BASIC cartridge.
Some modifications are necessary, so you can load it from DOS in order to load/save programs from/to disk

PCJRBIOS.COM
BOOT BASIC_XX.JRC
BOOT BASGAMES.IMG
BASICA

PCJRBIOS.COM fixes some of DOSBox's default interrupt handlers, and loads the PCjr ROM into segment D000h (BASIC part will be in D600h).
BASIC_XX.JRC is modified to reference segment D6000h, and instead of starting the interpreter it returns after booting, making it possible to boot DOS.

Thanks goes to VileRancour.









PS: With MESS I doesn`t have access to the content of the mounted disk image. So I am not able to load/save BASIC programs from/to the disk image.