Edit: First release here
Go play your Namco 20th Anniversary board without flipping your yoke wires!
Original post in spoiler now
Go play your Namco 20th Anniversary board without flipping your yoke wires!
Original post in spoiler now
I've been thinking about a post from this thread for a while. Namco tate rotation is backwards and as such I barely ever use my Namco 20th Anniversary pcb. Having dipped my toe into mame debugger (thanks @Hammy) I decided to give it a shot.
I'll update this first post with the patch as soon as it's ready, but it's not quite ready so I wanted to update folks on where I am, ask a few questions, and probably ask for some help. There some notes in here that will certainly be useful for anyone wanting to build a patch for the actual Ms. Pac Man (maybe even normal Pac Man) or the other anniversary boards. More than anything this disassembly is the key.
i/o for flipping is sent to 0x8b, so I force set that to 01 and patch all the other calls in the rom to nop.
4e72 is the address where the cocktail/flipping bit lives
flipping just flips the map and background, not the ghosts or ms.pac
most of the sprite flip checks look like "check for cocktail and check for p2, then do the sprite math" (ref) so I change them to "check for cocktail OR p2..."
The result is a currently running Ms. Pac Man in permanent p2 cocktail mode.
First question... permanent p2 means the game can be one player, or can alternate between p1 and p2, but always uses p2 controls. I think I can patch that so the controls get handed off between players. I think I could force it to be always p1 controls. I can see arguments for either. What would people want?
Second question... anyone applying this patch, do you actually desire the ability to set it back to "normal" somehow in the service menu? If so, what does "normal" look like for you?
Third question... how important is *also* flipping Galaga Because that one is being more difficult and if I can't solve it, I'll either ask for some help here or just post the patch anyway.
Looking at the Namco Anniversary boards, both of them have "cocktail" mode. which means that player 2 has the screen flipped.
this can work as a simple way to play in the alternate rotation and it also means that the code exists to flip the screen so hacking it is more a matter of permanently setting it to flip for P2.
I'll update this first post with the patch as soon as it's ready, but it's not quite ready so I wanted to update folks on where I am, ask a few questions, and probably ask for some help. There some notes in here that will certainly be useful for anyone wanting to build a patch for the actual Ms. Pac Man (maybe even normal Pac Man) or the other anniversary boards. More than anything this disassembly is the key.
i/o for flipping is sent to 0x8b, so I force set that to 01 and patch all the other calls in the rom to nop.
4e72 is the address where the cocktail/flipping bit lives
flipping just flips the map and background, not the ghosts or ms.pac
most of the sprite flip checks look like "check for cocktail and check for p2, then do the sprite math" (ref) so I change them to "check for cocktail OR p2..."
The result is a currently running Ms. Pac Man in permanent p2 cocktail mode.
First question... permanent p2 means the game can be one player, or can alternate between p1 and p2, but always uses p2 controls. I think I can patch that so the controls get handed off between players. I think I could force it to be always p1 controls. I can see arguments for either. What would people want?
Second question... anyone applying this patch, do you actually desire the ability to set it back to "normal" somehow in the service menu? If so, what does "normal" look like for you?
Third question... how important is *also* flipping Galaga Because that one is being more difficult and if I can't solve it, I'll either ask for some help here or just post the patch anyway.
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