Search found 4291 matches

by Dwedit
Tue May 26, 2020 5:00 pm
Forum: NES Hardware and Flash Equipment
Topic: Famicom Grey Screen (no games running)
Replies: 11
Views: 220

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: 12
Views: 614

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: 11
Views: 220

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: 274

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: 180

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: 1260

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: 1260

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: 1260

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: 664

Re: Most common mappers

Maybe DXROM and MMC6 should be added to MMC3 Family?
by Dwedit
Sun May 03, 2020 6:54 am
Forum: NESdev
Topic: Where to enable/disable IRQ in MMC3?
Replies: 7
Views: 603

Re: Where to enable/disable IRQ in MMC3?

CLI/SEI has no effect on NMI (Non-maskable interrupts) at all.
by Dwedit
Tue Apr 28, 2020 10:20 pm
Forum: phpBB Issues
Topic: Code tag - remove maximum height?
Replies: 1
Views: 840

Code tag - remove maximum height?

I think the Code Tag should have its maximum height removed.
by Dwedit
Mon Apr 27, 2020 6:37 pm
Forum: NESdev
Topic: NES Rotozoom
Replies: 20
Views: 1736

Re: NES Rotozoom

The source coordinates are changed incrementally (by addition) when the destination coordinates are changed by 1, so there's no multiplication or division once the increment values are calculated.
by Dwedit
Mon Apr 27, 2020 5:35 pm
Forum: NESdev
Topic: NES Rotozoom
Replies: 20
Views: 1736

Re: NES Rotozoom

Inverse affine texture mapping. If Destination X increases by 1, then source X and source Y have some fractional number added to them. Likewise with Destination Y increasing by 1. It's inverse mapping because you only need to care about moving the destination 1 pixel at a time, then the source locat...
by Dwedit
Mon Apr 27, 2020 5:25 pm
Forum: General Stuff
Topic: Dragon Quest (J) passwords reverse-engineering
Replies: 14
Views: 984

Re: Dragon Quest (J) passwords reverse-engineering

Double consonants are a real thing. It's the difference between the leaning tower of Pisa, and the leaning tower of pizza.
For example, "Bokken" (wooden sword) sounds kinda like "bok-ken" rather than bo-ken.