Search found 514 matches

by Miquel
Fri Jul 24, 2020 8:54 pm
Forum: Mega/SegaCD
Topic: mcd-verificator (CD core accuracy tests)
Replies: 26
Views: 141618

Re: mcd-verificator (CD core accuracy tests)

If signals like, for example, !TIME have a definitive impact in the address decoding of the MCD, I think they should be considered part of the address lines.
by Miquel
Fri Jul 17, 2020 7:07 pm
Forum: SGDK
Topic: Sega Genesis Dev Kit (SGDK)
Replies: 852
Views: 1122527

Re: Sega Genesis Dev Kit (SGDK)

@cloudstrifer: The sprites you show on the image are leftovers from past use, and innocuous since they are not linked in the list (“Link” field).
by Miquel
Tue Jul 14, 2020 3:52 pm
Forum: Mega/SegaCD
Topic: mcd-verificator (CD core accuracy tests)
Replies: 26
Views: 141618

Re: mcd-verificator (CD core accuracy tests)

No, I was saying that I thought not possible to have both the 32X and the SCD/MCD working from the cartridge slot at the same time, the MCD being emulated by the everdrive cart and a real 32X. So you have to choose between 32X or MCD, and no 32X-MCD combo. Am I wrong? The problem is that the 32X com...
by Miquel
Mon Jul 13, 2020 8:41 pm
Forum: Mega/SegaCD
Topic: mcd-verificator (CD core accuracy tests)
Replies: 26
Views: 141618

Re: mcd-verificator (CD core accuracy tests)

Both 32X and MCD working from the cartridge port...? I thought that was not possible...
by Miquel
Wed Jul 08, 2020 1:51 pm
Forum: Mega/SegaCD
Topic: mcd-verificator (CD core accuracy tests)
Replies: 26
Views: 141618

Re: mcd-verificator (CD core accuracy tests)

Hi KRIKzz, curiosity just spike up a lot with you messages, what is your project about? Perhaps a MegaCD/SegaCD in a FPGA? Just curious...
by Miquel
Thu May 14, 2020 1:32 pm
Forum: Megadrive/Genesis
Topic: VDP 8x16 Interlace Mode
Replies: 7
Views: 10067

Re: VDP 8x16 Interlace Mode

Also:
Working on 1:2 resolution is weird for graphical artist, or anyone else, I have never seen do it. Pixels are not square any more.
Doubled resolution is done by interlacing images (on different lines), not sure of the result quality on 90’s phosphor tv’s.
by Miquel
Tue May 12, 2020 10:35 am
Forum: Megadrive/Genesis
Topic: VDP 8x16 Interlace Mode
Replies: 7
Views: 10067

Re: VDP 8x16 Interlace Mode

You need twice the memory for tiles, backgrounds and sprites alike, and there is no much to start with if you use all the others planes. So it’s a case between resolutions vs diversity, where variety is already somewhat scarce. On lots of design questions memory is the underlying factor, today as ev...
by Miquel
Thu Apr 30, 2020 9:21 pm
Forum: Megadrive/Genesis
Topic: Alternative to Vasm assembler?
Replies: 27
Views: 31874

Re: Alternative to Vasm assembler?

As far as I know that can’t be done: the problem is that symbols '/' and '-' are interpreted as division and minus.
by Miquel
Sat Apr 25, 2020 6:35 pm
Forum: Megadrive/Genesis
Topic: Alternative to Vasm assembler?
Replies: 27
Views: 31874

Re: Alternative to Vasm assembler?

Very true - the C preprocessor can be run on gas files (use .S instead of .s for automatically doing so). Pragmas and defines and stuff can be used. This does make a gas assembler specific file very flexible compared to more traditional assemblers. I didn't know! investigation about to lunch. Defin...
by Miquel
Thu Apr 23, 2020 4:25 pm
Forum: Megadrive/Genesis
Topic: Alternative to Vasm assembler?
Replies: 27
Views: 31874

Re: Alternative to Vasm assembler?

After doing asm on several platforms I have to recommend gcc/gas. Why? Because macros are quite powerful, not perfect, but good enough to make extend programing simpler than others. (I know I touched a sensitive point, waiting for massive angry replies… ;) ) And to be honest GAS is probably the wors...
by Miquel
Tue Mar 31, 2020 1:41 am
Forum: SGDK
Topic: Brainstorming a way to hscan colors in SGDK
Replies: 10
Views: 12588

Re: Brainstorming a way to hscan colors in SGDK

Set the exception to jump to ram, there jump again to the desired h-int routine, you can use an absolute word jump, then wrote your routine in asm. It’s important to only push/pop the registers you’re going to use if you are cpu constrained; also there is the user stack pointer (usp) so you can swap...
by Miquel
Fri Mar 27, 2020 11:12 pm
Forum: SGDK
Topic: A challenge with tiles..
Replies: 1
Views: 3268

Re: A challenge with tiles..

Let’s first agree on what’s the situation: as I understand you have a map, a 2D matrix, where each element is a metatile of 5x5 tiles. Is that correct? Something like this: struct Tile { int indexOfTileOnVRAM; int colisionResponseIndex; }; struct Metatile { Tile tiles[ 5 ][ 5 ]; }; const Metatile me...
by Miquel
Tue Mar 24, 2020 11:53 pm
Forum: SGDK
Topic: The small-questions-not-worth-dedicated-topics topic
Replies: 5
Views: 6001

Re: The small-questions-not-worth-dedicated-topics topic

Here is my first one. I understand we use const to save data to the rom. But if I need to have a writable version of it in runtime, is there a proper way of doing things or do I just create a new variable and copy the values from a to b? Don't do that, you're making it worst. Use "const" for data t...
by Miquel
Wed Mar 04, 2020 6:15 pm
Forum: Hardware
Topic: Proper USB power mod for the Megadrive 2
Replies: 5
Views: 11091

Re: Proper USB power mod for the Megadrive 2

Usb requires to a least to power 500 mA, but there is no upper limit. But the point of this project, I think, is to reuse old usb chargers; I don’t see the scenario were data cables will be useful.
by Miquel
Mon Jan 06, 2020 3:22 pm
Forum: Megadrive/Genesis
Topic: General Gunstar Heroes rambling
Replies: 5
Views: 9536

Re: General Gunstar Heroes rambling

By dynamically loading I mean that, when the sprite changes, its tiles are loaded from rom to ram the previous frame, the space of vram that occupies the sprite is always the same. The idea is to have large animations for the main character, which is the most repetitive one, so can lead to visual sa...