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Jinks, on Mon Jun 27, 2011 6:36 PM, said:
Well that would be a good start is getting those games done, by "direct port" you mean what how much work would it be(how many hours per game of work)
Its pretty hard to estimate until you look at what you are up against. Typically you'll have to go through the following steps :-
- Find a good copy of the code.
- First pass disassembly ("fix-up" accounting for code and data).
- Look for and remove anti-piracy code (if any).
- 2nd pass disassembly ("fix-up" accounting for code and data).
- Check zero page usage. Ensure all ZP locations used are after 0x40.
- Put place holder routines in for any OS calls used (return sensible values).
- Move all RAM locations to fit 7800/XM architecture.
- Work around all self modifying code.
- Create the 7800 linear frame buffer (and initialisation) and point the code at it.
- See what you get (its going to look rubbish!
)- If you don't see anything fix it (this can take a ton of time).
- Once you see moving graphics, hunt through the code to find them. Replace with suitable 7800 ones.
- Rinse and repeat the last few steps until the game is functioning "correctly".
- Once you understand what the code is doing you could attempt to get rid of the linear frame buffer and use native 7800 sprites.
- Convert and replace the sound routines.
- Convert and replace the keyboard/joystick routines.
