Makaron WIP - To boot or not to boot | Dreamcast News - The Latest in Emulation and Homebrew

Makaron WIP - To boot or not to boot

June 16th, 2008, 17:04 Posted By: JKKDARK

Progress on the Sega Dreamcast emulator for PC.

I found and squashed a bug in new GD code. Not only Elemental Gimmick Gear boots again but it also cured Street Fighter Zero 3, which now seems to work just fine.

http://pics.livejournal.com/dknute/p...c6ch0/s320x240

http://pics.livejournal.com/dknute/p...c7x1p/s320x240

I've also devised a tweak to GD-DMA code for that accursed MPEG library. It interferes with SH4 main loop, effectively causing a temporary slowdown. This should not be a problem and is only visible during CD boot sequence, as BIOS decrypts the executable on the fly using thousands of 32-byte reads. As a side effect it fixes (or so it seems) those MIL-CDs that required SH4 speed to be reduced in order to load properly. One of these days I'll have to try and verify that on hardware, to see just how much of a slowdown G1 bus DMA transfer in background really is.
However, this is not yet the final solution to the problem. Sofdec library still expects some reads to start in close to zero time and I can't figure out why - still not conviced any code could be that braindead, so I'm not ruling out a bug on my side. For the time being I try to detect situations where DMA is started before GD buffer has anything in it, but every now and then this too fails. It looks awfully suspicious so I'll be investigating this next.
In the meantime, all Dream Preview GDs from Yuki boot now and here's a proof:

http://pics.livejournal.com/dknute/p...c847w/s320x240

http://pics.livejournal.com/dknute/p...c9e20/s320x240

http://pics.livejournal.com/dknute/p...cag06/s320x240

http://pics.livejournal.com/dknute/p...cbs5k/s320x240

http://pics.livejournal.com/dknute/p...cccwp/s320x240

http://pics.livejournal.com/dknute/p...cdp6t/s320x240

And as special bonus, an extra episode of How It's Made: Dreamcast by SEGA

Also, some of the titles above require modem and ISP settings stored in the FLASH. Modem is not exactly on the top of my TO DO list.

Okay, last batch for today:

http://pics.livejournal.com/dknute/p...de7dy/s320x240

http://pics.livejournal.com/dknute/p...dfz7d/s320x240

Ever seen VMU-compatible cell phones?

UPDATE: Oops, I've uploaded more images, but forgot to post them here. Here I brag about WinCE games and Biohazard 2 screens are missing... Fixed now :P

http://pics.livejournal.com/dknute/p...cs8qg/s320x240

http://pics.livejournal.com/dknute/p...ctk7z/s320x240

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