Search found 4297 matches

by Dwedit
Sun Jun 28, 2020 8:16 pm
Forum: General Stuff
Topic: Late 1980s / Early 1990s Memphis Style in NES Games
Replies: 16
Views: 730

Re: Late 1980s / Early 1990s Memphis Style in NES Games

Does this count?

chuchu-0.png
chuchu-0.png (3.98 KiB) Viewed 299 times
by Dwedit
Fri Jun 26, 2020 11:57 am
Forum: NESdev
Topic: Emulation speed vs actual NES speed (solved)
Replies: 16
Views: 574

Re: Emulation speed vs actual NES speed

If you think your code might be slow, a cheap way to measure CPU usage is to use PPUMASK. At start of frame, do something that you can see (such as monochrome mode, color emphasis, masking left 8 pixels, etc), then at the end of frame, turn that off. You can count your CPU load in scanlines. But unl...
by Dwedit
Fri Jun 26, 2020 10:05 am
Forum: NESdev
Topic: Emulation speed vs actual NES speed (solved)
Replies: 16
Views: 574

Re: Emulation speed vs actual NES speed

Sounds like you may be polling PPUSTATUS to check for the end of a frame? That can cause missed frames, don't do that (outside of the boot code that waits one frame).
by Dwedit
Fri Jun 19, 2020 7:51 pm
Forum: NESemdev
Topic: Chinese translation of Hitler no Fukatsu, MMC1 but larger than 256k
Replies: 2
Views: 538

Re: Chinese translation of Hitler no Fukatsu, MMC1 but larger than 256k

Oh gosh, if this expects a 256 + 32K game to use the bankswitching rules of usual 256K MMC1, but with last page stuck in the second 512K, there's no way this would ever work, it would need to be redone. Real 512K cartridges use CHR ROM selection bit to determine which 256K page to select, so you can...
by Dwedit
Tue Jun 16, 2020 9:24 am
Forum: NESemdev
Topic: Problems with palette data
Replies: 1
Views: 325

Re: Problems with palette data

There is only one background color. The other background colors found among the background palettes don't actually do anything.

Meanwhile, the Game Boy Color does things the opposite way, and does not share a single background color.
by Dwedit
Thu May 28, 2020 11:29 am
Forum: NESdev
Topic: Need help with compressed tiles
Replies: 9
Views: 1483

Re: Need help with compressed tiles

The font in that screenshot isn't compressed, it just aren't aligned to a usual 16-byte boundary. Use the + or - buttons in YY-CHR to change the byte alignment.
by Dwedit
Tue May 26, 2020 5:00 pm
Forum: NES Hardware and Flash Equipment
Topic: Famicom Grey Screen (no games running)
Replies: 13
Views: 1567

Re: Famicom Grey Screen (no games running)

Two bad CPUs sounds unlikely, it might be a problem on a chip or trace elsewhere.
by Dwedit
Tue May 26, 2020 12:10 am
Forum: General Stuff
Topic: SNES Doom development, Randy Linden
Replies: 21
Views: 3541

Re: SNES Doom development, Randy Linden

Could the Super FX do graphics compatible with Mode 7? Maybe it would have been possible to rotate the graphics 90 degrees, so you generate horizontal lines and display them as vertical.
by Dwedit
Mon May 25, 2020 7:43 pm
Forum: NES Hardware and Flash Equipment
Topic: Famicom Grey Screen (no games running)
Replies: 13
Views: 1567

Re: Famicom Grey Screen (no games running)

Something I see a lot in old console/computer repair videos is observing the address/data lines on an oscilloscope, just to see if the waveform looks "off" or not. You can sometimes tell by inspection if the square waveform doesn't look right, or has the wrong voltage range.
by Dwedit
Fri May 22, 2020 10:34 pm
Forum: NESdev
Topic: Expanding MMC1 from 256kb to 512kb
Replies: 4
Views: 1088

Re: Expanding MMC1 from 256kb to 512kb

Watch out for writes that reset the MMC1, or writes that change the CHR banking.
by Dwedit
Fri May 22, 2020 10:32 pm
Forum: NESdev
Topic: Hi All! Power-on state of skipped dot?
Replies: 1
Views: 1069

Re: Hi All! Power-on state of skipped dot?

Power-On state isn't actually all that consistent. On US NES, Reset state is far more consistent.
by Dwedit
Wed May 13, 2020 10:50 am
Forum: NESdev
Topic: Compiled stack proposal
Replies: 22
Views: 2203

Re: Compiled stack proposal

This is more of a thing for languages like C than actual assembly. Build the call tree, and allocate 'stack space'. And you will end up with multiple parallel trees once you consider Interrupt Handlers. From within your interrupt handler, anything called by that won't be using the same memory as som...
by Dwedit
Wed May 13, 2020 2:06 am
Forum: NESdev
Topic: Compiled stack proposal
Replies: 22
Views: 2203

Re: Compiled stack proposal

I would have called it "Stack Flattening".
by Dwedit
Tue May 12, 2020 11:03 pm
Forum: NESdev
Topic: Compiled stack proposal
Replies: 22
Views: 2203

Re: Compiled stack proposal

If you're trying to build a call tree, your root isn't just the entry point. Every possible 'thread' (interrupt handler) becomes its own root, and then function pointers make everything more complicated.
by Dwedit
Thu May 07, 2020 8:14 pm
Forum: NESemdev
Topic: Most common mappers
Replies: 2
Views: 1047

Re: Most common mappers

Maybe DXROM and MMC6 should be added to MMC3 Family?