Page 3 of 3

Re: Best Pac-man game for Dragon

Posted: Fri Nov 11, 2011 12:43 pm
by briza
rolfmichelsen wrote:Days quickly becomes weeks, but here's an update on how this mini-project is going. Not being a CoCo expert, I learned a lot of new stuff when actually starting to parse RSDOS filesystems... The RSDOS way of storing machine code programs is way more flexible than DragonDos, so a simple 1:1 conversion is not possible. I converted the file "KUNGFU.BIN" from the diskette named "kungdude.dsk", assuming that this is the file you are looking for.

The resulting DragonDos disk image is in the attached file. The disk contains 6 files, corresponding to the 6 "segments" constituting the CoCo program file. Each file loads as a machine code program despite the somewhat unorthodox naming.

SEGMENT.1 loads at address 1024 (this is the loading screen)
SEGMENT.2 loads at address 3584
SEGMENT.3 loads at address 359
SEGMENT.4 loads at address 512
SEGMENT.5 loads at address 544
SEGMENT.6 loads at address 2380
Program execution should start at address 3584, based on meta-data from the CoCo file. I haven't yet studied the content of segments 3-5 to see whether they actually trigger execution at some other address.

Simply doing LOAD "SEGMENT.2"; exec 3584 doesn't work, and I haven't yet figured out how to run this program or whether it will run at all on the Dragon. Next step is to look at what tricks are played with segments 3-6.

In the meantime, enjoy the loading screen by doing LOAD "SEGMENT.1" :-)

-- Rolf
Nice work Rolf :)

yeah that is the game i mentioned. U manage to get it working on a Dragon mate u will be loved by all dragon users :)
Rolf, Shame u never got into the coco's especially the coco 3, I reckon u could do a game easy enough :)

laters

Briza

Re: Best Pac-man game for Dragon

Posted: Fri Nov 11, 2011 10:45 pm
by rolfmichelsen
Some small progress. Segment 3 ensures that program execution starts at address 0x200 by overwriting the character input hook. Segments 4 and 5 loads at address 0x200 and contain some kind of loader. I need to look into the details here, but it looks like it messes with the SAM and moves all the program code into high memory (0x8000 and up) in addition to invoking some functions that I haven't yet disassembled. More investigation needed...

-- Rolf

Re: Best Pac-man game for Dragon

Posted: Sun Jan 22, 2012 9:11 pm
by zephyr
I have just uploaded a Dragon 64, 200 or upgraded 64K Dragon 32 conversion of this game to the Uploads section. The conversion was done by Steve Woolham.