nesdev.org

I didn't look that over in detail, and while that looks very powerful, it appears to depend entirely on CC65 based software. Unless I am missing something, it doesn't have generic special registers for writing error codes, does it?

I like the idea of using emulator scripts. Or I like Shiru was saying - a special register for error codes - I suppose this would require an open source emulator and knowledge of how to create this feature.

Good points. I have seen the halt trick before somewhere, I guess it is not too hard to trace that. If you are always going to have characters in CHR this could work, and even though it is extra coding, sometimes I find stepping code and checking regs a chore. I think (assuming you have a valid char...

I've been contemplating a lot of things, getting ready to do more serious stuff for the NES, (lower level 'driver' kind of things) and I was wondering if anyone codes runtime error messages into their games. Something like: ( ...some code..) #ifdef _DEBUG_ cpx #MAX_VALUE bcc continue pha lda #ERROR_...

Graphics resolution is not a problem. Many emulators can and usually do run at higher resolution than the NES. This allows some of the filters (ex. hq2x) to work.

^I think a Lau script overtop of the nes emulation would be able to overcome most, if not all of those limitations, though it would need to be customized to each game. I think any solution would have to be customized to each game anyway though.

Couldn't this be done with Lua scripting? It would seem to be the most flexible way, but I'm not sure if any emulators with Lua support creating higher res graphics than the nes resolution.

http://www.youtube.com/watch?v=IvDXZmS2MAU

Never really played Castlevania games ..too hard.

I have beat Life Force and Metroid in one life back in the day. (Metroid was using the trick to skip Kraid and Ridley.)

I was interested in trying this but it doesn't seem to work. Traceback (most recent call last): File "tilificatorgui.py", line 23, in <module> File "gtk\__init__.pyo", line 40, in <module> File "gtk\_gtk.pyo", line 12, in <module> File "gtk\_gtk.pyo", line 10,...

Yes, if family basic does range checking. I was guessing it may just take the low byte of the value and the code worked despite the error. But anyway, cool trick.

40 POKE &H7FD,A+255AND255 What the heck does 255AND255 mean? It doesn't look like Valid BASIC code, but I don't know Family Basic. Maybe: A+255 AND 255 I can understand ANDing - to get a byte value only.. not sure about adding 255, assumimg the above the same as: (A+255) AND 255 If Order of Oper...

This guy seems to know what he is talking about regarding 6502 BRK vs interrupt. http://www.youtube.com/watch?v=HW9AWBFH1sA
Sorry, I don't remember where in the talk he addresses it, but the whole thing is pretty interesting anyway.

Edit: Better link: http://www.youtube.com/watch?v=K5miMbqYB4E

Apparently this style of code is in many NES games. Metriod has the code that preserves X and Y. My question was basically if this is really a good solution, or if whomever coded it was outsmarting themselves with cleverness, but and I suppose it is a decent way to solve that problem.

Actually, I thought about it more..keeping the same structure, and using x,y for the table pointer (or zeropage) is okay, but then you would need two RTS or still use PLA,PLA,RTS to return to the code that first called into the jump table, so it might as well be done this way.

This is from SMB and is pretty smart: OperModeExecutionTree: lda OperMode ;this is the heart of the entire program, jsr JumpEngine ;most of what goes on starts here .dw TitleScreenMode ; <-- * .dw GameMode .dw VictoryMode .dw GameOverMode ;.... ;later somewhere else in ROM: ;$04 - address low to jum...