nesdev.org

i've never understood exactly how the square period stuff is modified by the sweeps. From my emulator: // Sweep tick (square waves only) if(HalfTick && c < 2 && count(ch.sweep_delay, ch.reg.SweepRate)) if(wl >= 8 && ch.reg.SweepEnable && ch.reg.SweepShift) { int s = ...

Related link, interesting reading: http://hitmen.c02.at/temp/palstuff/

In my emulator I got all SMB movies to sync without problems (with add/remove idle frames in the beginning). I update the controller data at the beginning of vertical blanking (scanline 241). With all NES movies, the controller data is updated regardless of whether the game polls the input 1, 2 or 0...

Dwedit wrote:I still don't understand why the FM2 format is so weird.

It was a design decision that the movie file format [of FCEUX] should be easily editable with a regular editor, without need for hex editing. Needs for copypasting and trimming arise every so often.

EDIT: nesmock now supports also fm2.

I wrote a new wiki article. http://wiki.nesdev.com/w/index.php/TAS As some people here might know, I'm a person who has had a part in introducing and promoting the TAS phenomenon in the world. Though I have officially stepped to the background from the scene, I still felt it natural to use TASes ext...

Here is my attempt at conveying the basics, beginning from fundamentals, in a short but organized manner. There are other tutorials, but I wanted to write one just for the exercise of it :-) In order to produce sound, you have to generate "PCM sound". "PCM sound" is a type of sig...

I recently needed to compress something (though my need went away before I actually used the decompressor), and I stumbled upon LZMPi compress , an LZ variant. It was written for the Commodore 64, but I ported it for the NES. It needs 64 bytes of RAM for history buffer tables ($6C0..$6FF), 35 bytes ...

The Mega Man series and Super Mario Bros. 2 USA (for Mario and Princess) used a sprite overlay trick to create characters of more than 3 colors. In case of Mega Man, the face is a distinct white-yellow sprite that is overlayed on the blue-cyan-black body, and in case of Mario and Princess, the eyes ...

So has anyone began the work at coding a PPP & TCP-IP stack on the NES? By now there should be plenty of example code to make the task easy. But there will certainly be some limitations; TCP does require some amounts of RAM. But if you overlook some compatibility issues, and e.g. assume that a p...

Surprises: Super Mario Bros and Bionic Commando seem to love JSR without RTS. Now that I think of it, that's because of how SMB1 implements switch statements. Fairly common in NES games over all, from what I have seen. I have disassembled a few games, and I have found this paradigm in more than hal...

This is the table of opcodes that I used for creating the micro-op data for my emulator. It contains all opcodes supported by it, grouped by the mnemonic. (The combination of mnemonic and the addressing mode is used to select the list of micro-ops for the opcode.) I have intentionally laid out the t...

How did you generate the Base64 (err, Base256? =D) encoded strings? Another program, or by hand? Sorry about taking many days to notice your post. phpBB only sent me a notification of your first post, and I did not know about the second one. Or the third one. Answer: Another program. For each micro...

JIT techniques could help a great deal with the CPU speed, but the PPU is a difficult problem to tackle, especially if you are aiming any kind of honorable level of accuracy. VGA can do smooth 4-way scrolling, but the addresses only wrap at segment boundary if I recall correctly, meaning that if you...

http://www.ioccc.org/ :P 2006 winner entries are finally available? Oh goodie! Thanks for telling. EDIT: Oh, and in all honesty, I was partially inspired by the 2005 winner that does a 6502 emulator (Commodore PET). But both algorithmically and structurally my emulator is very different. Mr. Sykes'...

thefox wrote:Very cool, sir. BTW what TAS movies/games depend on the RAM initialization state?

I seem to remember that I could not get the Wizards & Warriors TAS to sync before I added the RAM initialization. It could have been caused by something else, but that's what I did that made the difference.