SpritesMind.Net

All the Genesis consoles I've seen have a few wires going to the two work RAM chips. Any reason why that is? It seems intentional because even as the motherboards revisions change those wires remain. It doesn't seem to be a routing issue that required a few flying leads to fix. Given that the wires ...

You need to specify a linker script (e.g. -T mylinkerscript.ld). You can use the one included with SGDK called "md.ld". This will resolve the missing symbol "_start".

https://code.google.com/p/sgdk/

Stef wrote:To avoid CLR instruction use by GCC i use an infamous trick in SGDK.

Ha, that's brilliant. I'll definitely use it.

Chilly Willy wrote:You pass GAS the flags "-m68000 --register-prefix-optional". It still works on the very latest binutils.

Wonderful, that did the trick. Thanks!

I've noticed when assigning a volatile memory location to zero, gcc will emit a CLR instruction. Is there any way to force it to write a constant zero instead of using a read-modify-write instruction such as CLR? Also I recall there was some way to suppress the requirement of a percent sign on regis...

PSG is inside the VDP In fact $7F00-$7F1F on the Z80 side maps to $C00000-$C0001F on the 68K side, though it's not possible for the Z80 to control the data or control port in a meaningful way because of the bus size mismatch of 8-bit vs 16-bit. Only in Mark III compatibility mode (/M3 pin grounded)...

I suppose the fact that no one gets this right despite it being documented for at least 13 years goes to show how little this matters for practical purposes. I suppose it may come up in Atari ST or Amiga productivity software which probably give these instructions more of a workout than Genesis gam...

Bart had done some testing on this a few years ago, not sure if it's applicable to other 68Ks in the family or just the plain 68000:

http://emu-docs.org/CPU%2068k/68knotes.txt

Yes, of course! I had a different very specific goal in mind :) There are many things I wonder if they are possible using HBLANK. For example, is it possible to draw more sprites than what is theoretically possible (80) by changing the y values during HBLANK ? You can, and games like Castlevania Bl...

I agree, it's tiresome to see the same few posters who are routinely rude to people. They refuse to be civil and give the newbies a hard time excessively. To be honest, people like that can poison a small community and should not be tolerated. SMS Power has a very friendly community and I think this...

That's interesting, I have the JP version of the game and it doesn't have a heatsink. The chip and PCB are otherwise identical TBH I never checked the chip temperature, but the cartridge wasn't noticably warm after a few hours of use. I wonder if there are two versions of the hardware and one runs h...

I wonder if it would be better to have a sub-forum dedicated to music/YM2612 related issues?

Hello there, I was trying to make a 8MB or even 12MB cartridge. However, how exactly would one do this with 3x27c322 + 74LS139? I heard that $A00000-$BFFFFF are built in and can't be accessed. Is that correct? There's some issues when making cartridges larger than 4MB: 1.) 400000-7FFFFF is used by ...

I find it weird that the VDP would actually check the link value against the current sprite limit (64 or 80), internal cache might indeed be limited in size and cause potential issues when fetching above that limit but I do not see why the VDP would limit the acces to VRAM I had assumed that for sp...

don't know if it worths the money, perhaps I should simply plug it on the device and check current flowing ;) If the genny doesn't even power up, trash ! Oh I thought you were testing multiple units of the exact same AC adapter. Are these all Genesis power supplies you are testing, Or something els...