Search found 1547 matches

by Near
Mon Jul 08, 2019 3:06 pm
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

Sour managed to dig up the following links on the SNESdev Discord server. What else is needed? AWJ's trace on A14-A12 lidnariq's additional traces There's an SNESdev Discord? How many of these things are there? Heh. Anyway that's really good info, thank you! Are you aware HblankEmuTest displays hal...
by Near
Mon Jul 08, 2019 1:51 am
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

This is the key problem: I don't really know ... I'm not good at the hardware side at all. I'm hoping to get something like a cycle-by-cycle guide of when VRAM/OAM/CGRAM fetches occur and where, that we can then reverse into something meaningful. More than likely, one carefully designed test won't c...
by Near
Sun Jul 07, 2019 9:43 pm
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

Oh hey if you want to hate me ... :P https://archive.org/details/Bsnes-emulation-core-comparisons These were some older, stubborn bugs I had with bsnes way back in the day. I just finished implementing what should be a fairly cycle-accurate fetch/render sequence for the PPU (for mode 0-6 backgrounds...
by Near
Sun Jul 07, 2019 4:21 am
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

This could also be handled by the manifest which would specify the default content. A) I don't include unlicensed games in my own database, so it wouldn't help with the one game that needs 0x00. B) this won't handle any hypothetical cases that need more than a single fixed value (eg the Codemasters...
by Near
Sat Jul 06, 2019 2:34 pm
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

Ken Griffey Jr. also needs SRAM initialized to 0xFF or you get gibberish in the menus. The only exception is the Power Slide FX demo that must be initialized to 0x00 or it crashes. I just let Power Slide FX crash currently and use 0xFF. The more proper solution that people will hate is, games should...
by Near
Wed Jul 03, 2019 2:13 am
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

tepples wrote:How hard would it be to build an 8:7 PLL to turn the 21.47 MHz master clock into 24.55 MHz to give 31960.2 Hz output?
The hard part for me would be performing the soldering work.
by Near
Tue Jul 02, 2019 9:09 pm
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

I'm fine with changing it to 32040Hz, though, if that's what's been determined to work the best? But was just a bit curious. I found that d4s' Breath of Fire II (German) fan translation's streaming HDMA audio engine was extremely timing sensitive, and didn't work well at 32000hz. qwertymodo reverte...
by Near
Mon Jul 01, 2019 12:15 am
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

Speaking of which, do you have a build of bsnes/higan I could use to produce trace logs? Ah yes, I still need to make that for you ... can you compile from source? If so, it'll save me some effort making a Windows binary on my other dev box. I'll use bsnes v107, which is identical to higan once you...
by Near
Sun Jun 30, 2019 6:58 pm
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

I gave fixing the whole DMA/IRQ timing issue a try, too. Wrote a pretty simple test suite to validate a few scenarios on hardware. Waiting on the hardware results, but for now I'm assuming higan is correct and my implementation gives the same result as higan for the test. It also fixes the power ra...
by Near
Sun Jun 30, 2019 4:40 pm
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

Oh cool. So it returns a possibly unstable value when it happens. This is worth looking into. Will do that first then. Many, many years ago (ten, probably), I wrote a test ROM to start trying to emulate this behavior. I loaded it onto my SNES copier (Super UFO 8.3j), and it froze the system. The co...
by Near
Sat Jun 29, 2019 2:16 pm
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

I have no idea what happened but it always looks correct now, using same test build when report created. :confused: I must have some really random glitchy stuff going on. :grumble: Whoever you are, I wish you were around when I was bug-hunting my SNES core, hahah. You're doing a thoroughly awesome ...
by Near
Sat Jun 29, 2019 6:53 am
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

According to anomie's docs, writing to $420B (DMA enable) allows the CPU to continue up to the point where it reads the next instruction's op code before DMA starts. That's another thing that also happens. That's part of the DMA<>CPU synchronization. This is a really complex topic to talk about ......
by Near
Fri Jun 28, 2019 5:37 am
Forum: SNESdev
Topic: Mesen-S - SNES Emulator
Replies: 370
Views: 178183

Re: Mesen-S - SNES Emulator

If the CPU is halted (i.e. for DMA) while /NMI goes low, the NMI will trigger after the DMA completes (even if /NMI goes high again before the DMA completes). In this case, there is a 24-30 cycle delay between the end of DMA and the NMI handler, time enough for an instruction or two. The 24-30 cycl...
by Near
Fri Jun 21, 2019 6:59 pm
Forum: GBDev
Topic: STAT bug vs STAT IRQ blocking
Replies: 3
Views: 6691

Re: STAT bug vs STAT IRQ blocking

That sounds more complete than any info I've seen so far. So it sounds like a cheap way to emulate this is to test for the STAT IRQ flag being 0 before firing the STAT bug IRQ. Simulating the STAT interrupt enable bits all being set for one cycle (M or T? though it likely doesnt matter here) would b...
by Near
Fri Jun 21, 2019 12:42 pm
Forum: GBDev
Topic: STAT bug vs STAT IRQ blocking
Replies: 3
Views: 6691

STAT bug vs STAT IRQ blocking

Seems there's two conflicting behaviors. The infamous STAT bug that is required in games like Legend of Zerd supposedly acts as follows: * when on a non-GBC system, and writing any value (even 00) to STAT, while the display is enabled, and you are in mode 1 (Vblank) [and possibly in Hblank as well],...