Search found 787 matches

by Sik
Thu Apr 18, 2019 5:37 pm
Forum: Cartridge
Topic: Size limits
Replies: 22
Views: 4032

Re: Size limits

Wait, it's for that shmup where you were using a map photo for the background? I mean, huh, dunno, but maybe it'd be better for you to use pixelart and reuse tiles as needed. There's no reason why you should be spending that much on a scrolling background unless you go full Silpheed with its prerend...
by Sik
Wed Apr 17, 2019 7:40 pm
Forum: Video Display Processor
Topic: Help scale and rotation sega genesis
Replies: 27
Views: 1869

Re: Help scale and rotation sega genesis

In terms of DMA transfer, you end up using the same time yeah (transferring a 256px wide buffer in H32 mode will take as long as transferring a 320px wide buffer in H40 during vblank). What you reduce is CPU usage when doing software rendering — in particular, you only need to render 80% as many pix...
by Sik
Tue Apr 16, 2019 9:36 pm
Forum: Cartridge
Topic: Size limits
Replies: 22
Views: 4032

Re: Size limits

Fusion is limited to 6MB, Regen is limited to 5MB, yeah. BlastEm seems like it may support 128MB, though no guarantees on this as nobody has attempted that yet. The header needs to have "SEGA SSF2" instead of "SEGA MEGA DRIVE" to enable this, however (real hardware doesn't care, mind you). You'll pr...
by Sik
Tue Apr 16, 2019 3:13 pm
Forum: Cartridge
Topic: Size limits
Replies: 22
Views: 4032

Re: Size limits

Eh, it's just 64Mx16 Flash with the Sega mapper with 8-bit to specify the page numbers (enough to address 128MB). Any implementation that conforms to the Sega mapper interface should do (a CPLD should be good enough to implement the mapper). I'd suggest to commission such a board rather than wait on...
by Sik
Mon Apr 15, 2019 1:14 pm
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 792

Re: Compiling an emulator for enhanced Megadrive

Yeah, interlaced modes were a waste (given the lack of a way to double the horizontal resolution) and were indeed reportedly some of the most complex ones. But the fact they were so hard to implement may have meant they had some distorted view of it? Or that it was too tangled up with the non-interl...
by Sik
Sun Apr 14, 2019 4:21 pm
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 792

Re: Compiling an emulator for enhanced Megadrive

Mega Drive has always been in the wild compos as far as I remember (where any systems that don't fall in existing categories go).
by Sik
Sat Apr 13, 2019 2:48 pm
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 792

Re: Compiling an emulator for enhanced Megadrive

Extra palettes wouldn't be a small addition though. The logic would be indeed tiny on the die, but don't forget CRAM is also on the die, and that is what would eat up a signficant amount of space (every bit adds to the die usage, and it'd be 576 more of them if we still stick to 9-bit colors!). Esse...
by Sik
Sat Apr 13, 2019 12:00 pm
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 792

Re: Compiling an emulator for enhanced Megadrive

I hear you. But the Megadrive+MegaCD combo is something that exists that SEGA themselves created, and in itself has its own set of constraints and restrictions. It's not a hypothetical Megadrive that has arbitrary improvements, which only emphasizes the stock MD's shortcomings. A present day implem...
by Sik
Sat Apr 13, 2019 12:50 am
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 792

Re: Compiling an emulator for enhanced Megadrive

The problem is that if you're looking at 1988, huuuh, the price was precisely the issue. The VDP has support for some improvements as it is (more VRAM, more colors, genlock onto other VDP), yet including that would have added to the cost. They also had to cut down some features from the VDP while re...
by Sik
Wed Apr 10, 2019 12:11 pm
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 792

Re: Compiling an emulator for enhanced Megadrive

Yeah, System C2 isn't compatible in any form. Not only there's no Z80, the YM2612 is at a different address, I/O is completely different, there's a watchdog, CRAM is 68000 mapped, it uses the VDP's own EDClk instead of the external one the Mega Drive uses, it uses the VDP's DRAM mode (which is an in...
by Sik
Wed Apr 10, 2019 2:17 am
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 792

Re: Compiling an emulator for enhanced Megadrive

The colors in the palettes are 15-bit (5-bit per compoent). For comparison, Mega Drive's colors are 9-bit (3-bit per compoent). EDIT: also System C2's external CRAM has way more than 8 palettes, but they work through bank switching (it exists mainly to thwart quick attempts at bootlegs). Without doi...
by Sik
Tue Apr 09, 2019 3:27 pm
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 792

Re: Compiling an emulator for enhanced Megadrive

For what's worth it, a lot of the stuff mentioned there is possible on top of the existing hardware: System C2 has more colors (using external CRAM) and better color depth (15-bit) Tera Drive has 128KB VRAM (which also doubles transfer bandwidth) Sega CD and 32X add more audio channels (both slots h...
by Sik
Tue Apr 09, 2019 4:25 am
Forum: Megadrive/Genesis
Topic: Compiling an emulator for enhanced Megadrive
Replies: 42
Views: 792

Re: Compiling an emulator for enhanced Megadrive

Dgen is a very nice emulator to modify. However, we've had this same discussion on Nesdev about NES and SNES enhancements several times. The conclusion each time is that it doesn't make any sense. If you want to make unlimited games, target a modern platform. "Console X, but enhanced such that only...
by Sik
Mon Apr 08, 2019 12:18 am
Forum: Megadrive/Genesis
Topic: Enhanced Tectoy Megadrive ?
Replies: 1
Views: 105

Re: Enhanced Tectoy Megadrive ?

Aren't those the ones based on the same shit AtGames used? I recall those allowing more colors and more VRAM. Then again, there was at least one Tectoy clone which implemented a J2ME VM aside from the usual Mega Drive side (this was used for that Guitar Hero knock-off), of course that isn't going to...
by Sik
Sun Apr 07, 2019 3:44 pm
Forum: Cartridge
Topic: EEPROM mapping for homebrew
Replies: 9
Views: 462

Re: EEPROM mapping for homebrew

Double post but it just hit me: I'm being dumb. Whether it's dealing with two or three support chips (SPI vs EEPROM) is not a big issue, the bigger issue was dealing with ROMs over 2MB. If left in $200001 then one would need to resort to implementing $A130F1 and that'd make things a lot more complex...