nesdev.org

I think having a 256 LUT, which outputs 0 to 99. You only need 100 entries for that ;P Well, you did mention speed... Up the 256 to 512bytes.. ByteBin2Dec: lda TableDec,x ldy SwapLowNybble2BCD,x ldx TableDec,y rts Input is byte in X. Returns BCD in two bytes via X:A. Edit: I guess it doesn't make a...

The problem isn't that, the problem is doing it quickly. What's the fast method for doing this on the NES? I think having a 256 LUT, which outputs 0 to 99. And for the last digit in the 100s place, simply check of the original byte is greater than 200 (populate a 2) or greater than 100 (populate a ...

CoCo's video chip is an MC6847 Video Display Generator, whose datasheet indeed specifies half a color burst period per pixel. At that, rate, the scanline can reasonably be 454, 455 (standard), or 456 dots long. It turns out, according to note 6 on page 7, that the MC6847's scanline is of the standa...

Anyone have a favorite quickstart guide and/or toolchain recommendations for the Megadrive? My only irrational requirement is I want to to never have to see gnu assembler syntax :P I hate gnu 68k assembler syntax :yuck: I'm probably one of the only one that uses this in MD/Gen dev: http://john.ccac...

tepples wrote:

Mother of god.....

Such as to make screens where a picture of a character appears on the real thing but a skull and crossbones appear on emulators. http://i.imgur.com/OIohv9S.png OK probably Fusion wasn't the best for this (due to the display off gap being visible with it) but oh well. How many colors are you updatin...

If you're sticking with a rectangle design for metasprites, then you can easily store it in column format and use that speed up for removing whole columns for clipping (instead of individual sprites). How long does it typically take to write a sprite on the NES? I know for the SNES, most games took ...

You can always code the core game engine in assembly and then the "boring" parts in C, those "offline stuff" such as intro screens, menus, transitions, etc - which make your game look pro but are a bummer to do. Regardless of what I posted, I still find C related stuff on these ...

One thing I like from Shiru's examples, is he wrote a whole library of asm functions to handle all common game routines. They aren't explained very well, so I don't use them, but once you write a good 'update PPU with new tiles' asm function, you really don't have to do it again. Every game after t...

So, I'm still pretty new to writing C for the NES. I keep feeling like it's actually going to wind up taking more of my time using it than if I just continue to build well-honed idioms in 6502. I also find myself feeling somewhat irritated with all the "noise" it generates. So much stuff ...

Interesting :) is there the same for signed multiplication (which is more useful) ? I guess it only requires different lut. Edit: I found the signed version which add some cycles at the end of the multiplication operation, signed operands process a bit slower because of that, still that is a fast i...

This could be repurposed for '816. The routine has a large overhead of T1 loading because it's setup for sequential calls were T1 doesn't change, but you could easily switch that to indirect, removing the self-modifying code, and seriously cut that loading over head down by a lot. Also, the tables a...

On the GBZ80, the processor I'm most familiar with, I generally try to keep all of the temporary data I'm working on in the CPU's registers (A, B, C, D, E, F, H, and L) at all times. If I find that I can't, that's almost always a cue for me to rethink my code or to refactor, wrapping some inner log...

...it always seemed to me to be a pretty common refrain among 6502 enthusiasts that, at the very least, the zero page compensated for the paucity of registers. For example, the Wikipedia article on the 6502 makes the comparison I'm confused. You say that 65x coders refrain from using this point of ...

Yet the 6502 itself draws plenty of Atari 2600, Commodore 64, and NES homebrew development, even with all the weirdness of the TIA, VIC-II, and PPU. In general, the scope of game design for those systems is not in the same league as the SNES or systems of that generation. There's also this communit...