Search found 857 matches

by Sik
Wed May 22, 2019 12:26 pm
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 4724

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

I believe it's just how they decided to handle the SH-2 side for the cartridge slot. My point was more that they did leave the strobe connected and hence they didn't remove the ability to write back to cartridge (even if only the Mega Drive side can do it). It's not like with /DTACK where not wiring...
by Sik
Wed May 22, 2019 12:43 am
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 4724

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

The write strobe is definitely passed to the cartridge slot, isn't it? I mean, otherwise games wouldn't be able to save. That's a completely different issue.

I wonder if not wiring /DTACK was an attempt to thwart Game Genie and the like (what addresses are used in those cases?).
by Sik
Tue May 21, 2019 5:46 pm
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 4724

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

Just looked up, SVP registers cover $A15000-$A15009 while 32X registers are all from $A15100 onwards. In other words, the exact addresses don't overlap.

That makes the whole part about leaving out SVP support particularly bad if /DTACK was indeed the only issue…
by Sik
Sun May 19, 2019 5:29 pm
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 4724

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

$A14xxx has the TMSS-related ports (on systems with TMSS, that is).
by Sik
Fri May 17, 2019 4:40 am
Forum: SGDK
Topic: Sega Genesis Dev Kit (SGDK)
Replies: 789
Views: 346484

Re: Sega Genesis Dev Kit (SGDK)

*insert shameless plug for SLZ* :​v I mean, SLZ has a tool written in C , only uses up as much RAM as the decompressed data (and the function call :​P) and the SLZ format is documented . And on the Mega Drive side it's literally just a single function call, so it should be easy to learn. Though I sh...
by Sik
Tue May 14, 2019 8:05 pm
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 4724

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

It is :​D (which also means DMA will not hang on areas where the 68000 usually would) It seems they just assumed DMA would only be used with memory that would always respond in time.
by Sik
Mon May 13, 2019 7:01 pm
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 4724

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

Actually is 3 cpu cycles per read/write cycle, and then at least an extra is needed cycle to store data somewhere in case of read, or anyway a micro-instruction is always 2 cycles, so at the end is always 4 cycles. Add 2n more cycles if the cpu operation is delayed. But the proper read/write cycle ...
by Sik
Fri May 10, 2019 10:02 pm
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 4724

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

It's even messier with the 65816: http://forum.6502.org/viewtopic.php?f=4&t=2438 On top of that… let's not forget about the operands. The fastest instructions on 68000 that access memory are 8 cycles (4 to read opcode, 4 to read/write a word). Not sure what it is on 65816, but from what I recall pre...
by Sik
Fri May 10, 2019 9:49 pm
Forum: Blabla
Topic: Strong Buzz for new Amstrad CPC game
Replies: 11
Views: 849

Re: Strong Buzz for new Amstrad CPC game

From what I recall, CPC is entirely bitmap based, with the only real perk being scrolling… so yeah, don't expect much. No idea if it can use cartridge memory as framebuffer, but this is Batman Group, so maybe they just have a fast blitter. Especially since in-game it definitely can't cheat that much...
by Sik
Thu May 09, 2019 5:48 pm
Forum: Blabla
Topic: Strong Buzz for new Amstrad CPC game
Replies: 11
Views: 849

Re: Strong Buzz for new Amstrad CPC game

Isn't that just a prerendered animation?
by Sik
Wed May 08, 2019 10:01 pm
Forum: Blabla
Topic: Strong Buzz for new Amstrad CPC game
Replies: 11
Views: 849

Re: Strong Buzz for new Amstrad CPC game

They didn't show much footage but I'm going to guess it precomputes and/or unrolls a lot (and their comment about needing a memory expansion for a disk release which even then would be limited seems to imply so — the "main" release is a cartridge). And raster effects :​v
by Sik
Mon May 06, 2019 3:27 pm
Forum: Mega/SegaCD
Topic: Questions on writing a new Mega CD emulator
Replies: 112
Views: 7268

Re: Questions on writing a new Mega CD emulator

Dumb question but: isn't the spiral at a physical level basically just a long string of bits? Is there any reason for a preservation format to store a disc as anything other than those raw bits? (even with uncorrectable bits since, erm, that's precisely what the error correction scheme in the standa...
by Sik
Sat May 04, 2019 1:33 pm
Forum: Mega/SegaCD
Topic: Questions on writing a new Mega CD emulator
Replies: 112
Views: 7268

Re: Questions on writing a new Mega CD emulator

I'm gonna laugh if we end up redumping every single CD from scratch using a Mega CD/LD simply because it's capable of dumping all that. That's gonna get real expensive, real quick with the high and rapid failure rate of Sega CD hardware. I mean, we probably want to do maintenance on the mechanical ...
by Sik
Fri May 03, 2019 11:17 pm
Forum: Mega/SegaCD
Topic: Questions on writing a new Mega CD emulator
Replies: 112
Views: 7268

Re: Questions on writing a new Mega CD emulator

I'm gonna laugh if we end up redumping every single CD from scratch using a Mega CD/LD simply because it's capable of dumping all that. I'd strongly advise you ignore the abomination that is iso+mp3 though, and never support it. Make the user find at least a halfway decent image file to start with. ...
by Sik
Fri May 03, 2019 11:50 am
Forum: Super 32X
Topic: Using 32x as a 3rd plane, possible?
Replies: 28
Views: 3671

Re: Using 32x as a 3rd plane, possible?

It works on Kega Fusion, right now I'm trying to figure out what's going on. Maybe this program ignores RV, but is not that simple, I need more time. Fusion is not accurate :​O) Reminds me, Chaotix tries to show "DEVELOPED FOR USE ONLY WITH SUPER32X SYSTEMS." if you plug it into a MD directly witho...