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This isn't hard to change is it? You could have the NMI routine take care of screen updates and split screen and exit and return to the selected engine with the same basic structure. I'm actually working on this right now. This may be a bit much for the OP (not really that complex) but I use somethi...

When learning binary most people learn the weight of the bits in decimal: 01010101 128, 64, 32, 16, 8, 4, 2, 1 0 1 0 1 0 1 0 1 = 64 + 16 + 4 + 1 = 85 With a signed byte you can think of the 7th bit (on the left end) as a value of -128 11010101 128, 64, 32, 16, 8, 4, 2, 1 1 1 0 1 0 1 0 1 = -128 + 64 ...

I still play UT99.. not nearly as much - and those that remain are hardcore - but I still play sometimes.

This is really nice. From the video it looks very true to the original. This is still a fun game - I tired to see how far I could get after watching "King of Kong" - I think I was able to break 100K points once or twice (after a lot of practice). Any plans to implement the new arcade level...

Oh yeah that's much better. Thanks

Added one last revision to that post. It could be improved more, but the idea is there anyway.

Thanks for the feedback. I did know about .local in a macro, fixed. I think I fixed the return address problem in a slightly hacky way, but I am happy with it.

Specific to ca65, but maybe workable in other assemblers: Call any compatible subroutine and pass stack parameters and no messing around with return address: .macro call function, param1, param2, param3, param4, param5, param6 lda #>@return pha lda #<@return-1 pha .ifnblank param6 lda param6 pha .en...

I'm not sure if bunnyboy didn't want to teach signed numbers for a reason, but you would be a lot better of using signed values for moving the ball. You could reduce the size and complexity of the code that changes the ball's position: MoveBall: ;this routine simply moves that ball lda balldirection...

Probably not exactly what you are looking for, but perhaps some information that might be helpful: You should try using 'make' and the makefile linked here: http://forums.nesdev.com/viewtopic.php?t=7691 It might take a bit of tweaking depending where you put stuff, but it does track all dependencies...

Thank you for your interesting posts. ...as X only occupies the lowest 5 bits of nametableAddrLo. Therefore, you can save 2 cycles by replacing.... Good point, I assumed I still had overlapping bits, but yes, I do have 5 bit shifts left and 0..31 will fit in 5 bits. Maybe someone can post a lookup t...

This is mostly for fun/sharing. I have come up with this method of calculating the nametable address, curious as to other's methods or any criticism: nametableaddress = y * 32 + x + $2000 Observation: Shift y value left one bit (x2) and the value in the high nibble should be added to the high(ppu ad...

I see, thanks.

Is it specific to C? I can be pedantic too, so I don't want to be wrong. I assumed it was just the idea of jumping into the middle of an unrolled loop to make up the remainder of transfers. (Reading Wikipedia..) Wikipedia does say that it was a technique used in assembly and Duff simply implemented ...

I kind of like this: .segment "RODATA" duff_copy_ram_code: tsx stx $E; save stack ldx $F; load fake stack txs ldx 2 clv duff_branch_value: bvc jump_in copy: pla sta PPU_DATA pla sta PPU_DATA pla sta PPU_DATA pla sta PPU_DATA pla sta PPU_DATA pla sta PPU_DATA pla sta PPU_DATA pla sta PPU_DA...

..you should probably add a loop arround the long pla/sta chain. For example if the chain transfer 16 ($10) bytes and that you want to transfer $25 bytes, you just execute the last 5 iterations of the chain, then you do the entire loop 2 times. It does do that. I had read that battletoads (I think ...