Search found 109 matches

by Near
Fri Apr 09, 2021 5:46 am
Forum: Megadrive/Genesis
Topic: VDP FIFO and DMA questions
Replies: 3
Views: 1947

Re: VDP FIFO and DMA questions

This is *really* impressive information, thank you so much for sharing! But, wow, every time I ask a question, the answer is an additional ten layers of crazy deep to go down the rabbit hole ^-^; The pixel timings of 342/420 are easy enough to follow. ... what in the world are half-lines? o_O I coul...
by Near
Fri Apr 09, 2021 2:12 am
Forum: Megadrive/Genesis
Topic: VDP FIFO and DMA questions
Replies: 3
Views: 1947

VDP FIFO and DMA questions

Been trying to implement all the knowledge here, hoping someone can help with some tricky points for me ^-^; First, DCLK/EDCLK. I get that EDCLK was a last-minute thing to stabilize H40 mode and that it makes some of the MCLK cycles longer. With either mode, you get 171 access cycles for H32 mode, a...
by Near
Sun Apr 04, 2021 8:57 am
Forum: Megadrive/Genesis
Topic: Question on Golden Axe II
Replies: 4
Views: 1176

Re: Question on Golden Axe II

That was exactly it, thank you so very much!

This hardware is really giving me a lot of trouble it seems ^-^;
by Near
Sat Apr 03, 2021 11:00 am
Forum: Megadrive/Genesis
Topic: Question on Golden Axe II
Replies: 4
Views: 1176

Re: Question on Golden Axe II

Shoot, I do that too. auto VDP::writeDataPort(n16 data) -> void { io.commandPending = false; //DMA VRAM fill if(dma.io.wait) { dma.io.wait = false; dma.io.fill = data >> 8; //falls through to memory write //causes extra transfer to occur on VRAM fill operations } //VRAM write if(io.command.bit(0,3) ...
by Near
Fri Apr 02, 2021 8:04 pm
Forum: Megadrive/Genesis
Topic: Question on Golden Axe II
Replies: 4
Views: 1176

Question on Golden Axe II

I notice my emulator is getting a garbled "Sega" logo screen, and partially garbled intro screen immediately after it. Looking at the trace, it loads d0 with #$ffffffe3, and then shortly after just starts spamming loop: move.l (a0)+,($c00000); dbf loop; instructions for big ~64K loops from ROM to VR...
by Near
Fri Apr 02, 2021 4:35 am
Forum: Super 32X
Topic: Questions on emulating the 32X
Replies: 14
Views: 2835

Re: Questions on emulating the 32X

For whatever it's worth, I posted ares v119 with my 32X emulation source to https://ares.dev I really appreciate everyone's help here. If anyone wants to work on 32X for their emulator, I would be most happy to return the favor. Feel free to ping me with any questions and I'll try to answer them. Th...
by Near
Thu Mar 25, 2021 10:30 am
Forum: Super 32X
Topic: Questions on emulating the 32X
Replies: 14
Views: 2835

Re: Questions on emulating the 32X

- a debugger (a must. 'definitely would pay for it) I have a pseudo-debugger. You can see, edit, and export any RAM contents, create trace logs (with optional masking and automatic loop elision) of all chips and their associated interrupts, certain debugging information like DMA requests (limited s...
by Near
Thu Mar 25, 2021 5:42 am
Forum: Super 32X
Topic: Questions on emulating the 32X
Replies: 14
Views: 2835

Re: Questions on emulating the 32X

I found the key to most of my issues: I was failing to type-extend DMULS/DMULU first to 64-bits, so they were being truncated to 32-bits. With that fix, compatibility is now around 80-90% or so. Not bad! VDP outputs a signal called !YS which is active when nothing/backdrop color is being output Is t...
by Near
Wed Mar 24, 2021 10:18 am
Forum: Super 32X
Topic: Questions on emulating the 32X
Replies: 14
Views: 2835

Re: Questions on emulating the 32X

Not having much luck with rendering. Take Amazing Spider-Man: Web of Fire. This is the Mega Drive layer: https://i.imgur.com/V8PrqN7.png And this is the Super 32X layer. https://i.imgur.com/ZwbZru6.png The combination is supposed to look like this: https://i.imgur.com/f6ggTiT.png Throughbit is never...
by Near
Tue Mar 23, 2021 10:34 pm
Forum: Super 32X
Topic: Questions on emulating the 32X
Replies: 14
Views: 2835

Re: Questions on emulating the 32X

I figured out the bug with the HINT(2) tests, a dumb logic bug I made refactoring ^-^; I was incrementing the counter on both Hblank start and end by mistake. It is indeed HCOUNT of 5 == every 6th line. Thank you! Also, reading the HCOUNT register returns the set value and not the current counter, o...
by Near
Mon Mar 22, 2021 11:32 am
Forum: Super 32X
Topic: Questions on emulating the 32X
Replies: 14
Views: 2835

Questions on emulating the 32X

Hi all, I started on a 32X emulator. It's far enough to run Chaotix, but not much else. https://near.sh/posts/20210318071942/chaotix.png Problem is, it's feature-complete. I implemented the VDP, PWM, FIFOs, DREQ, vector 4 address (0x70-0x73) as RAM, and the half of the SH7804 games use: full cache e...
by Near
Wed Mar 10, 2021 2:51 pm
Forum: Mega/SegaCD
Topic: Popful Mail
Replies: 14
Views: 9630

Re: Popful Mail

Wow!! You are just a saint! <3 It does indeed fix the booting problem, thank you again! I went and audited every single io.cpp and io-external.cpp register after this one, but sadly didn't find any more fixes ^-^; I got nerd-sniped yesterday with the SVP, but I did take a look briefly at the sprite ...
by Near
Mon Mar 08, 2021 7:03 am
Forum: Mega/SegaCD
Topic: Popful Mail
Replies: 14
Views: 9630

Re: Popful Mail

Now next challenge: let's find out why sprites are invisible in all existing Sega CD emulators during the intro of Radical Rex. This one has been puzzling me for quite some time now (sorry to hijack thread :oops: ) Please, by all means. I have a few more Popful Mail bugs, but I should at least spen...
by Near
Fri Mar 05, 2021 6:56 pm
Forum: Mega/SegaCD
Topic: Popful Mail
Replies: 14
Views: 9630

Re: Popful Mail

Writing zero to the wordram control reg (from either side) does not affect 2M wordram assignment. Ishmael, thank you SO VERY MUCH !!!! https://i.imgur.com/CTa1rc9.png I can't tell you how happy this has made me. Definitely made my entire week. Really, really thank you so much! I really got lost thi...
by Near
Thu Mar 04, 2021 2:25 am
Forum: Mega/SegaCD
Topic: Popful Mail
Replies: 14
Views: 9630

Re: Popful Mail

This has become my white whale ^-^; So I'm aware both Kega Fusion and Gens require the 'perfect sync' option to run this game. I've set my emulator to sync all components after each component steps by one cycle. I can confirm that's working by seeing my FPS drop from 204fps to 78fps. My 68K core's t...