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Extending the MR. Do ROM set? The Z80 challenge...


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#1 Nebulon OFFLINE  

Nebulon

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Posted Thu Jan 11, 2018 4:14 PM

Any Z80 programmers out there looking for a pet project?

 

If so, you could make the world a better place by adding more levels to the arcade version of Mr. Do. 

 

You know how levels 2 through 9 each have a path/tunnel shaped like a number?

 

What if there were additional levels that had paths shaped like letters (A through Z). 

 

Otherwise, exactly the same game. No additional features -- just more mazes. The existing game logic should do the rest on its own.

 

 

Anyway, food for thought for anyone out there looking for something interesting to hack away at. I'd do it myself, but I'm completely ignorant of Z80 machine language programming.



#2 x=usr(1536) OFFLINE  

x=usr(1536)

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Posted Thu Jan 11, 2018 7:40 PM

Any Z80 programmers out there looking for a pet project?

 

If so, you could make the world a better place by adding more levels to the arcade version of Mr. Do. 

 

You know how levels 2 through 9 each have a path/tunnel shaped like a number?

 

What if there were additional levels that had paths shaped like letters (A through Z). 

 

Otherwise, exactly the same game. No additional features -- just more mazes. The existing game logic should do the rest on its own.

 

 

Anyway, food for thought for anyone out there looking for something interesting to hack away at. I'd do it myself, but I'm completely ignorant of Z80 machine language programming.

 

If the level designs are derived from the bitmaps for the numbers involved, it might just be a case of flipping a byte from 0x09 to 0xFF and you've potentially got 254 levels ('0' isn't used, IIRC).  I'd be willing to bet that anything above 0x0F would glitch the display (or crash the game), though, since it only seems to be set up to base the screen designs on single digits.  Could be wrong, though.

 

Somehow, though, I suspect that they're stored as data rather than generated based on the character set.



#3 Nebulon OFFLINE  

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Posted Fri Jan 12, 2018 3:27 PM

I think you're suspicions are correct -- especially from the 'D' shape on the first level and the unusually distorted shapes of the numbers for some of the levels. 



#4 Nebulon OFFLINE  

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Posted Fri Jan 12, 2018 3:29 PM

Hmmm.... This is interesting (even includes comments):

 

http://tech.quartera...tml.aspx?g=1827

 

Not a lot of info in there though. Mostly stuff we already know.

 

Was kind of hoping for the actual listing.


Edited by Nebulon, Fri Jan 12, 2018 3:39 PM.


#5 x=usr(1536) OFFLINE  

x=usr(1536)

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Posted Sat Jan 13, 2018 1:15 AM



Hmmm.... This is interesting (even includes comments):

 

http://tech.quartera...tml.aspx?g=1827

 

Not a lot of info in there though. Mostly stuff we already know.

 

Was kind of hoping for the actual listing.

 

That one's also very outdated.  The current MAME driver is here.

 

Someone familiar with Z80 dis/assembly would need to tear apart the original game, figure out where the screen drawing routines are (the MAME debugger may help with this), and go from there.  That's not going to be me, however.



#6 Nebulon OFFLINE  

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Posted Sat Jan 13, 2018 4:11 AM

A buddy of mine is a crack 6809 machine language programmer. That's not going to help much for Z80 though. 

 

Oh well, it's just a matter of time before someone bored enough (or nostalgic enough) jumps in and tackles this one. 



#7 Nebulon OFFLINE  

Nebulon

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Posted Sat Jan 13, 2018 4:12 AM

 

That one's also very outdated.  The current MAME driver is here.

 

Someone familiar with Z80 dis/assembly would need to tear apart the original game, figure out where the screen drawing routines are (the MAME debugger may help with this), and go from there.  That's not going to be me, however.

 

I suppose I should ask though.... Where can you find the MAME debugger?



#8 x=usr(1536) OFFLINE  

x=usr(1536)

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Posted Sat Jan 13, 2018 8:07 AM

 

I suppose I should ask though.... Where can you find the MAME debugger?

 

It's built-in, and you start it with the -debug switch (the name of your MAME executable and path to your ROMs will likely vary from the example below):

 

mamearcade64 -debug -rompath /path/to/your/roms/ pacman

 

That'll start Pac-Man with the debugger window open.  In the debugger, type 'help' for a list of commands.

 

For the rest, you'll need to hit up Google - going into how it works is a deep rabbit hole, and pretty much outside the scope of what we can get into here.  One hint: search for MESS as well as MAME debugger usage.


Edited by x=usr(1536), Sat Jan 13, 2018 8:09 AM.





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