nesdev.parodius.com

[Disch]

C/C++ won't help you much/at all in your efforts to program the NES. Break out your 6502 references and start reading. Get a copy of nestech.txt for the register descriptions, and maybe pick up a tutorial or two.

http://www.obelisk.demon.co.uk/6502/reference.html <--- one of the best 6502 references. It won't teach you 6502 but is great for looking up quick stuff.

http://nesdev.parodius.com/ndox200.zip <--- nestech -- not exactly 100% at times, but still gives you a pretty good idea of what you need to know. The $2xxx register descriptions in it are a 'must-know'

I don't have any recommendataions for tutorials. GBAGuy made one which I hear is decent -- however it's the only one I know of and I've never actually looked at it so I don't know if it's any good or not.

[Celius]

Well, I downloaded nestech a long time ago, and I've read gbaguy's tutorial, but I don't know if I've been to that other link you have there. I am just not sure what to do for designing levels, every method seems to be innacurate, except for one which I know is really accurate, which I AM NOT going to use. This is it:

lda #$00
sta $2007
lda #$01
sta $2007
etc..

loading one tile at a time. Very accurate, A ROM HOG. I'm pretty sure it works on every emulator. I don't know. I just wish that frickin' method would work. I hope I stumble upon a good method someday. I want alot of background data in my game, and I don't want to have to do something dumb to make backgrounds. Yeah, I'm going to have ALOT of background data in my game, so I NEED to find a good method. There has to be one good method at least. incbining nam files SUCKS. UNRELIABLE. I will maybe have to look in SMB1's source, and see they're method, if I can. the only problem is it's SUCH A BIG CODE! I don't even want to think of Final Fantasy 3s. Well, if you get a reliable method, let me know, I'll be here on the computer until I die. Or have to go to school and work.

[Disch]

You need to get familiar with other addressing modes. And employ some looping:

Absolute,X:

[Quietust]

I've looked through the tutorials by GBAGuy, and I can safely tell you that they are NOT any good - they pretty much rely on substandard emulators like nesticle and will NOT run properly on real hardware. To name a few examples I've seen:

* Not waiting 2 frames on startup
* Not disabling frame IRQs
* Writing to VRAM while the PPU is trying to render

It also has some significant errors in the instructions:
* It labels $2000.6 as "Execute NMI on Sprite Hit" (supposed to be PPU master/slave toggle, which has no effect on the NES)
* It claims you can only set one color emphasis bit at once (probably straight from Marat's documents)
* It claims the SPR-RAM address register $2003 is 16-bit (double-write) like $2005/$2006
* It initially tells you to write to SPR-RAM one byte at a time to $2004 (but later tells you how to do it properly via Sprite DMA, neglecting to tell you that you STILL have to specify the initial SPR-RAM address)
* It tells you to use .db to declare variables in RAM and suggests that it will actually use the initial value
* It claims the first $2005 write is vertical scroll and that the 2nd write is horizontal - in reality, it's the other way around
* It initially tells you to handle joypad input by reading $4016 and checking each bit individually (though it eventually teaches you to do it properly)
* The author CAN'T SPELL
* The author expresses LOTS of uncertainty throughout the tutorial, leading to the conclusion that he doesn't actually know anything about the NES in the first place.

The tutorials are very, VERY outdated, and I would not recommend using them.

If you want a decent tutorial, I would recommend McMartin's NES 101 tutorial. Though it assumes that you know 6502 assembly reasonably well, it is reasonably up to date with current knowledge of how the NES works and, as a bonus, it will actually work on a real NES!

[tokumaru]

[tokumaru]

[blargg]

[beneficii]

[beneficii]

[mbrenaman]

Sorry to butt in, but this is the first I'm hearing of having to read from $2002 before using $2005/6. I tried adding "bit $2002" before my writes to them in the scroller I'm making and it went from working fine to scrolling very jerky in Nintendulator. The only time I read from $2002 is when my main code is wait for the next NMI. Very weird that it went from working fine to scrolling jerky. Am I really supposed to read from $2002 every single time I use $2006 or will just once every NMI be fine?

EDIT : I'm confused.

[Disch]

[Guest]

Disch, thank you. I thought my just the read before Vblank was working hehe. Thanks ..... Hehe Mr. Brenaman.

[Disch]

oh whoops... 'mbrenaman' -- not Mr. Brenaman. haaha sorry XD I coulda swore it said 'mr'.

[Celius]

Dude, Gba guy's tutorials SUCK. He's just like, "Oh yeah, I don't know how this works, but i would be very greatful if someone found out how." Yeah, that sucks. He always uses these crap methods of doing stuff I think his example of Vblank routines is BAD. And everything else. If you want to be really good with 6502, read something else.

[beneficii]