Megaman and other NES hacks for PCE

 Update 7/25/11

 I've made some small updates to Megaman PPU and APU emulation. Screen now turns 'off' (though 1 frame delay) and the screen is better centered (can see the floor in Iceman's level).

 I've decided I should tackle some game challenges that actually motivate me. I like Contra, Robowarrior, etc but I'm just not really motivated enough to work on them. Like I have with Megaman. So, I've decided to pick to other games to work on that I think will keep up my motivation. Megaman 2 and Metroid. Work has already started on Megaman 2. I have to write new emulation code to support dynamic H and V mirroring changes/updates, but that's not too much of a problem as I've worked out the details. Megaman 2 only uses it for the stage select and map areas, nothing in game per se. So anyway, yeah.. Megaman 2. Should be fun.


Old news:


 Update 3/22/11
 - Links can be found at http://pcedev.wordpress.com

 Update: 10/19/09
 - Added Duck Tales 2.

 Update: 10/14/09
  - Added Contra project to the list and links.

 Update: 10/10/09

 My site is gone, so the old links don't work. You can find current links here. I don't want to provide direct downloaded links here as the project files themselves more than likely violate the linking rules of this forum. Aside from that I haven't worked much on these, but did a few small audio bug fixes.

 Current NES to PCE projects:
 
 Megaman 1
 Castlevania 1
 Contra
 RoboWarrior
 Super Mario Bros 1
 Dragon Warrrior 1 (not uploaded yet)
 Duck Tales 2 (This isn't 100% tested to the end. Some sound/graphic port writes might be missing. Unconverted graphic port writes can freeze/glitch the game. I could use testers to play through this game.)

 I have some downtime coming up, so I'll probably try out some other simplish NES conversions.


 Note: This release should work with other emu's besides mednafen. Works on the real hardware.


 About:

 This a project to hack the original NES rom to run on the PCE. This method simulates/translates the PPU, APU, IO, and MAPPER on the backend of the system while the game code runs natively on the PCE's CPU. Writes and reads to I/O ports are replaced with JSRs. Once the game is up and running smoothly, additional modifications can be added like; upgraded audio(CD audio if CD project), 16color tiles/sprites, 512 color palette, bigger sprites, bigger sprite per scanline limit, up to 32megabit rom(if hucard - 600megabytes for CD), etc.

 This an open source project - so do what you want with it 

When I assemble this, It does not work. Since the emuiators cannot run the assembled code.

Good try, Though.

Yes, is it supposed to do anything yet?

pceas megaman.asm

Just a blank screen in Ootake and mednafen.

Just the frame work is setup in that version (so you can see how it's structured). It only has the UNROM mapper reg code so far. No PPU code. I'll upload updated versions as I go. I should have some sort of (limited) video running by this weekend. I'm still in the process of tracking down all the mapper and ppu read/writes in the original game code.

 I have D7 of $2002/$2000 working with the NMI routine and $2005/2006/2007 writes/operations as well in version 0.3

 EDIT:

 A more playable demo

 Thanks to Disch for the sanity check 

Tried it on Magic Engine. Just displayed the title. Wouldn't actually start. =(

Tried it on Magic Engine. Just displayed the title. Wouldn't actually start. =(

 Because I switched around start and select. I'll fix that later. So try pressing select

I think A and B are also reveresed.

I think A and B are also reveresed.

 Hah! I'll put that on my list to fix 

It worked, plus I discovered I had also forgotten to set my select button.

very nice!   

It would be awesome if I could play this on my real PCE / TG-16...

Oh my god!! It works much better than I expected! Can't wait for a version 1.0...
I will love to change it's graphics and make MM1 look GOOD!

*So many possibilities.. My mind is blowing!*

How similar are the Genesis and Neo Geo? I heard they both use a combination of 68K+Z80 family chips.

How similar are the Genesis and Neo Geo? I heard they both use a combination of 68K+Z80 family chips.

 Just the video hardware alone is completely different. The Neo Geo is an all sprite display system. There are no backgrounds - just a static non scrolling window overlay. The sprites can be chained together in huge horizontal strips. It was really impressive back in the day. IIRC, the z80 has it's own bus to its own roms - not mappable by the 68k like the Genesis. Then there's the Neo Geo's YM2151 which has more waveforms for the operators and more operator algorithms iirc. Don't forget the ADPCM chip too. Pretty different systems.

The genesis/mega drive can really switch the CPU.
I had a "powerbase converter" to play my SMS software,but some titles had problems with the VDP that is not fully compatible.
I tell that the 68000 CPU don't has the 64k memory limits,so more complex coding is possible(UCLinux on Palm).