Search found 40 matches

by Marty
Fri Jul 22, 2005 12:55 pm
Forum: NESemdev
Topic: Sayoonara 2001.3/2001.4
Replies: 28
Views: 19911

In the struggle to make the puzzle pieces fit together, this setup will at least make the commercial games and pputime2 work properly: void Cpu::Ram::Reset() { std::memset( mem + 0x000, 0xFF, 0x3F0 ); std::memset( mem + 0x3F0, 0x00, 0x010 ); std::memset( mem + 0x400, 0xFF, 0x1F0 ); std::memset( mem ...
by Marty
Tue Jul 19, 2005 5:03 am
Forum: NESemdev
Topic: ppu loading rom or using ram
Replies: 21
Views: 11156

I rewrote my own movie code recently and took a different approach. I decided to scrap the controllers and instead just feed on the $4016 and $4017 ports only. The gain is precise accuracy and that any device can be hooked up and switched in real-time without affecting and/or complicating the movie ...
by Marty
Wed Jul 13, 2005 7:41 am
Forum: NESemdev
Topic: cpu speed
Replies: 32
Views: 15614

Sonic 3D Blast 6 doesn't work with $4017 set to 0 on power-up, presumably because it's a hacked dump. Other than that, no other game seem to cause any trouble when default-enabling frame IRQ's.
by Marty
Mon Apr 18, 2005 9:03 am
Forum: NESemdev
Topic: Some questions here..
Replies: 24
Views: 14350

Muchaserres wrote: And this one.. heh, any ideas on what is that?
Thx in advance.
Just some wacko obviously..
by Marty
Wed Apr 13, 2005 12:22 pm
Forum: NESemdev
Topic: Some questions here..
Replies: 24
Views: 14350

The only thing I'm missing here (I hope) is the little delay between when a NMI is signaled and the time when it is actually served. I read somewhere that it's just a few PPU cycles, anybody can tell me for sure how many? An interrupt will get serviced right after the CPU finishes its current instr...
by Marty
Sun Apr 03, 2005 4:27 pm
Forum: NESemdev
Topic: a few MMC3 questions
Replies: 14
Views: 8462

Hyde wrote:I implemented this on my emulator in the hopes that it would fix Star Wars (E), but nothing happened. Oh well...
The IRQ counter goes supposedly off one time during VBLANK when the game accesses the palette via $2006/$2007.
by Marty
Fri Apr 01, 2005 4:25 am
Forum: NESemdev
Topic: a few MMC3 questions
Replies: 14
Views: 8462

What exactly do you mean by that? Do you just update the counter on A12 rising edges and then not allow the counter to be decremented for 16 cycles? Exactly, on every rising edge I clock the counter only if 16 or more PPU cycles have elapsed since the previous occurred. As for 16 cycles, it's a nic...
by Marty
Thu Mar 31, 2005 2:20 pm
Forum: NESemdev
Topic: a few MMC3 questions
Replies: 14
Views: 8462

It could be that your DMC DMA timing is off.
Speaking of SMB3, does anyone know if the leftmost tile at the beginning of the statusbar flickers on the real thing as well?
by Marty
Tue Mar 29, 2005 6:33 am
Forum: NESemdev
Topic: a few MMC3 questions
Replies: 14
Views: 8462

nesdev wiki MMC3: "The MMC3 scanline counter is based entirely on PPU A12, triggered on rising edges (after the line remains low for a sufficiently long period of time)." Has it ever been measured how many cycles this sufficiently long period of time is ? I'm currently guessing it at each hblank, b...
by Marty
Sun Mar 13, 2005 1:37 pm
Forum: NESemdev
Topic: Loopy_T to Loopy_V: When?
Replies: 10
Views: 7198

I've changed the code in my emulator to reflect this, that is, by putting it on PPU dummy scanline cc offset 299 instead of 256. I haven't noticed any problems with the few time sensitive games I've tested so far so I think I'll stick with this for now. If it causes problems with any other game I'll...