nesdev.org

WedNESday's VBlank time is 2269 CC's. This is the most allowed for blargg's VBlanks test allows. Set it any higher or lower and it fails you.

I've downloaded so many copies of the ROM but they all do the same. On WedNESday it runs fine, just like on most other emulators. But how do FCE Ultra and Nestopia manage to make it run differently? (What do they know that we don't...)

Nestopia is so much faster now on my P3-450 then it used to be. I do have one concern though. FCE Ultra and Nestopia seem to run Super Mario Bros. differently from other emulators. The demo is fine but when you actually run the game, you only get one level that does not exist in the game and is all ...

hap wrote:A lot. Did you read Brad Taylor's NTSC 2C02 technical reference ? If you didn't yet, now's the time. It explains what the PPU cycles 'do'.

Should I use that reference or this one http://www.nesworld.com/dev/ntscpput.txt

A pixel is not rendered on every PPU cycle. There are 341 PPU cycles per scanline... but only the first 256 of those cycles render pixels. The other cycles do other things. I know about that. 256 Pixels are rendered and the rest of the CPU time is HBlank (about 28.3 cc's). What do the remaining PPU...

Ok, I am going to implement my afforementioned method of rendering, i.e. execute a full CPU instruction, followed by rendering 3 pixels etc. Draw (Instruction Time - 1) * 3 Pixels Execute Instruction Draw 3 Pixels (Remaining Cycle) With this method am I guarenteed to have an accurate CPU/PPU/APU rel...

Ok, I want to implement some form of accurate timing on my emulator. However, I don't want to rewrite my CPU for cycle for cycle timing. Can I do it this way. Opcode == 0xA9 (LDA Immediate) Do Operation... Clock Cycles = Clock Cycles + 2; DrawPixel( NumberofPixels ) (NumberofPixels == 2 * 3) { ... }...

I know that people say the you should not trust NEStress and all that. One emulator DOES actually pass the test in NEStress and that is FCE Ultra. So it is possible to get a pass. WedNESday does not process graphics in the way that you have described. Here is how it works for WedNESday; (Scanline fo...

Here is the code that sets the hit detection flag. if( !Transparent ) if( Background && Sprites == Visible ) if( SpriteNo. == 0 ) if( !( !( Sprite Clipping && Spritex < 8 ) ) if( Spritex != 255 ) if( BgPixel != Transparent ) SetFlag (Phew...) Can anyone see what is wrong with this co...

Sorry guys problem solved, my fault; if( Register[0] & 0x08 ) memcpy( &CPU.Memory[0xC000 - (Register[0] & 0x04) * 0x1000], &File[0x10 + (Register[3] * 0x4000)], 0x4000 ); not; if( Register[0] & 0x08 ) memcpy( &CPU.Memory[0x8000 + (Register[0] & 0x04) * 0x1000], &File[...

ALL MMC1 games are playing up.

Yes I am changing the ROM data (I was going to do all of the trapping later). Could that be what is effecting it?

I still can't get this to work, and I am literally ripping out my hair over it. Here is a sample of my code; if( Register[0] & 0x08 ) memcpy( &CPU.Memory[0x8000 + (Register[0] & 0x04) * 0x1000], &File[0x10 + (Register[3] * 0x4000)], 0x4000 ); I have ANDed Register[3] with 0x0F but th...

I never meant to be mean or anything...



I think the that there are 2 bottom lines when it comes down to emulation. 1. You write the emulator for fun or 2. You write the emulator for serious accuracy. I think that 1 wins hands down every time.

Since a real NES can run all games using the same engine, a good emulator will do also. Leave the number of VBlank scanlines at 20 as this is correct. Making your emulator custom for certain games is what very old (and therefore crappy emulators used to do). Never introduce hacks for games, if it do...

Thanks for letting me know that. Just to clarify about the BRK bug. If an interrupt occurs during the BRK opcode then the opcode is not finished at all?