Search found 409 matches

by strat
Sun Mar 17, 2024 9:33 am
Forum: NESdev
Topic: SMB - 128 Lives Display Fix?
Replies: 4
Views: 524

Re: SMB - 128 Lives Display Fix?

This is what the 65816 code does LDA $075A ; $0D:8E22: AD 5A 07 INC A ; $0D:8E25: 1A CMP #$0A ; $0D:8E26: C9 0A BCC CODE_0D8E56 ; $0D:8E28: 90 2C STZ $E4 ; $0D:8E2A: 64 E4 STZ $E5 ; $0D:8E2C: 64 E5 You replaced the STZ, a convenience instruction, with LDA #0/STA, trashing the value loaded from Numbe...
by strat
Sun Feb 04, 2024 3:56 pm
Forum: General Stuff
Topic: Can you start from scratch and create a version of Super Mario Bros. and distribute the ROM?
Replies: 25
Views: 1847

Re: Can you start from scratch and create a version of Super Mario Bros. and distribute the ROM?

The summary judgement in Capcom vs. Data East has an interesting tidbit As noted previously, because the Court found, under the 7 extrinsic test, that five of the special moves in Fighter's 8 History were similar to five protectable moves in Street Fighter 9 II, Capcom is entitled to submit these fi...
by strat
Sun Feb 04, 2024 9:50 am
Forum: General Stuff
Topic: Can you start from scratch and create a version of Super Mario Bros. and distribute the ROM?
Replies: 25
Views: 1847

Re: Can you start from scratch and create a version of Super Mario Bros. and distribute the ROM?

The only thing that is genuinely not copied in any shape or form is the soundtrack. But that's about it. And it didn't even bother to copy two essential features in SMB, the running/jumping physics and koopa shell. Giana has one new idea, hiding bonus rooms in random pitfalls, and even that is a ba...
by strat
Sun Dec 17, 2023 11:02 pm
Forum: NESdev
Topic: Namco IPL Interface
Replies: 11
Views: 4313

Re: Namco IPL Interface

Sometimes developers leave some debug-related code in the release builds because they don't want to create more bugs by removing it so soon before submitting the release candidate for certification. I'd take a wild guess it was generally more cost effective in programmer time to disable the debug f...
by strat
Wed Jan 25, 2023 6:00 pm
Forum: NESdev
Topic: new technologies for developing on NES
Replies: 19
Views: 3380

Re: new technologies for developing on NES

Drag wrote: Tue Jan 24, 2023 10:45 am it's not, because an AI gains no understanding of causation or theory or anything meta by looking at examples, unlike a person
Soooo... this means we're not getting Skynet anytime soon?
by strat
Mon Jan 09, 2023 6:15 pm
Forum: NESemdev
Topic: Ppu and Cpu multithreding sync
Replies: 5
Views: 759

Re: Ppu and Cpu multithreding sync

I tried making a multithreaded emulator as an exercise (and eventually adapted it to just being a single thread). It used semaphones on any event where the CPU and PPU relied on each other, such as writing to vram or reading PPUSTAT. There was a third thread to synchronize both per scanline. It's no...
by strat
Mon Jan 02, 2023 7:35 pm
Forum: General Stuff
Topic: What is one thing about a retro console/computer's specifcations that you would change?
Replies: 34
Views: 3354

Re: What is one thing about a retro console/computer's specifcations that you would change?

BTW, Nintendo didn't just loose the war big time to the PS2, the Gamecube almost made them go bankrupt, despite still ruling the portable market with the GBC, GBA and the Pokemon craze. It's kind of surprising this thread has so much dissection of the Gamecube, but nobody's mentioned N64 should've ...
by strat
Sat Oct 29, 2022 9:39 pm
Forum: NESdev
Topic: NESFab
Replies: 15
Views: 3959

Re: NESFab

Very nice, especially the support for fixed-point math. I would put in bcd math, also. My attempt at a programming language had built-in bcd routines automatically called on vars declared with "bcd".
by strat
Sun Sep 11, 2022 3:22 pm
Forum: NESemdev
Topic: CPU/PPU sync approach
Replies: 2
Views: 1294

Re: CPU/PPU sync approach

Trying to make a cycle-stepped PPU, though it still uses the same CPU and runs the cpu cycles * 3 for each instruction. It's not clear to me how exactly the shift registers work with the palettes, so this is my code. On a scroll divisible by 8 it looks fine but as it scrolls the attributes become mi...
by strat
Tue Aug 30, 2022 7:57 pm
Forum: NESemdev
Topic: CPU/PPU sync approach
Replies: 2
Views: 1294

CPU/PPU sync approach

This is my main emulation loop (CPU core is Marat Fayzullin's). It runs a scanline worth of cpu then draws a scanline. SMB seems to run fine and that's supposed to be the litmus test for new emulators, but Balloon Fight's scrolling (which uses timed code to set the scroll below the status bar) is of...
by strat
Sat Mar 05, 2022 1:09 pm
Forum: General Stuff
Topic: Why isn't there a MOTHER/Earthbound reverse engineering team?
Replies: 30
Views: 5533

Re: Why isn't there a MOTHER/Earthbound reverse engineering team?

A decompilation is quite different to a disassembly, both technically and legally. A clean-room decomp can be argued to be legal, while a disassembly is just a mechanical transformation that ships copyrighted code. Nintendo may not have taken action against such, but they have reasons including PR ...
by strat
Sat Dec 11, 2021 8:54 pm
Forum: General Stuff
Topic: Masayuki Uemura, designer of the NES (and SNES), has died, age 78
Replies: 8
Views: 1473

Re: Masayuki Uemura, designer of the NES (and SNES), has died, age 78

What exactly did he design: the looks of the console, the technical specifications, the CPU+APU or PPU LSIs, a combination of these? Going by this YT interview and the GlitterBerri article, it looks like he spec'd the system and Ricoh did the 2A03 and PPU chip designs (there's a 45 min. interview w...
by strat
Thu Dec 09, 2021 5:40 pm
Forum: General Stuff
Topic: Masayuki Uemura, designer of the NES (and SNES), has died, age 78
Replies: 8
Views: 1473

Re: Masayuki Uemura, designer of the NES (and SNES), has died, age 78

He probably was.

Thank you, Mr. Uemura. So many wonderful games were possible because of your work.
by strat
Sun May 23, 2021 4:49 pm
Forum: NESdev
Topic: D (decimal) flag
Replies: 9
Views: 3280

Re: D (decimal) flag

(Edited to clarify the overflow flag.) The carry flag pretty much is your general use flag. And if you need an unconditional branch, anything is going to be more wasteful than just using jmp (bvc might work if the numbers always stay within a positive or negative range - the flag is set by any math ...
by strat
Fri Apr 30, 2021 9:38 pm
Forum: General Stuff
Topic: Zelda II - The Adventure of Link... SUCKED
Replies: 31
Views: 18194

Re: Zelda II - The Adventure of Link... SUCKED

Elevators in underworld -- it just doesn't make any sense, why is there an elevator. It should look ancient and crumbling, no electricity, etc. They probably use pulleys :p - Zelda 1's dungeons were very much about spatial puzzles peppered with fun combat; you're trying to figure out how the dungeo...