nesdev.org

The nesdevwiki website has been down since at least Friday. Anyone know why, or when it will be back up?

I'm trying to think of ways that the rendering code might be optimized. It should be possible to draw 2 pixels per operation by using a short (16x4) look-up table to convert the planar bits to a 32-bit int. Do you happen to know if there's a penalty for unaligned DWORD-length writes on the iPhone's ...

I'm having trouble figuring out a good way to get the code running on Windows. Are you doing all your testing on the iPhone?

What is the current speed of execution on the iPhone? Does it require frameskipping?

The Commodore 64 Programmer's Reference Guide is a good source as well. One thing you should keep in mind is that the NES CPU does not have decimal mode, so any references to decimal mode in 6502 documentation should be ignored. (You can set and clear the flag with SED/CLD, but it does nothing.) Wha...

You do not need a per-pixel renderer to fix the gross graphical errors in games like Rad Racer and Crystalis. That only requires implementing rendering per scanline using the VRAM address. If your target platform is the iPhone or other handheld devices, then per-pixel rendering would be far too slow...

When I have some free time this week, I'll take a closer look at the code. It doesn't look all that complicated, so I can probably get it working on Windows with SDL (not the best platform, but very simple to get something up and running without writing too much extra wrapper code). By the way, you ...

Do you have a version of this software that compiles on Win32 (2k/XP) with free software? If so, I can probably fix it for you. That's the only platform I have access to, however.

You shouldn't be keeping "Scroll X" and "Scroll Y" registers. All rendering should be done using the VRAM address, and the VRAM address should be updated from the latch as described in Loopy's document at the appropriate times. The only pure "scroll" value in the actual...

Yes, that's exactly what I'm looking for. Thanks!

The standard dimensions of the NES video output (256x240) are of course well known. Brad Taylor's documentation does an excellent job of describing what the PPU is doing during this time, and Blargg's NTSC filter creates artifacts very close to those seen on the real system. (About all that is neede...

Hi, folks. I'm a bit interested in making a program that'll calculate the Mandelbrot set, but I don't want to reinvent the wheel. Does anybody have any links to 6502/6510 ASM code for generating this fractal? I've already done quite the search through Google and 6502.org and while there is plenty o...

Would the source code for MAME be usefull as a reference on how the Yamaha chips work? Not really, for several reasons. First of all, it's not designed for good readability - it has sparse comments and it's difficult to follow the logic because of all the poorly named variables and structures. (Thi...

it uses odd banking, and stuff like RAM under ROM. (you can write to ROM which writes to RAM underneath, then you switch the ROM out) Hmm. Interesting. This was standard practice on the Commodore 64 (which also used a 6502 derivative) but I haven't seen it in any NES/Famicom games previously. I hav...

I recreated the OPL3 (aka YMF262) in my FPGA and I have it playing some FM synth tunes. It's a simple matter to drop the code for that into my NES core to get VRC7 audio. Any possibility that you could write a document on how the VRC7 actually works on a hardware level? Yamaha's documentation on it...

I don't know why kevtris refers to the 109 as the MIMIC-1, they may function the same, but I don't think Tengen has anything to do with the 109. The N109 chip predates the MIMIC-1, yes. We know that Tengen licensed some games from Namco, such as RBI Baseball and Pac-Man; it seems likely that they a...