More Sega Saturn WIP pics, based off the latest fixes for the system:

Fixed a SCU DSP bogus bug with flags, fixed SMPC intback command, moved it inside a command and hooked up the SMPC direct mode inputs. This allows the following Sega Saturn goodness:

The diagnostic cart is now operational too, and it really shows how bad is our current Saturn emulation (and some very lovely Engrish as well 😉 )

Finally fixed the PCG beam position hooks in Sharp X1 HW. There was a bug with vblank / vsync bits so beam positions wasn’t making any sense. Fixing that makes the thing to finally upload character data properly without any hacks.

Also, fixed Kanji ROM read thru ports 0x1400 – 0x14ff, makes Asteka 2 to finally show correct gfxs too:

And ANK ROM reading too, used to draw romaji text in Maison Ikkoku – Kanketsuhen:

EDIT: Fixed a silly bug with PCG index loading, fixes regression with Exoa 2 – Warroid and X1C Demo:

EDIT2 (24 March 2011): Fixed a z80dma that caused erratic port increments, fixes gfxs in Legend of Kage and Gandhara:

EDIT3 (25 March 2011): Fixed bank i/o bit behaviour and a bug with kanji vram and height. This bug-fix allows Lupin the 3rd, Take the A-Train and Makai to boot and fixes gfxs in Makai and Luna City.

Added Sharp MZ-2000 support to MESS, that is a stripped down version of the Sharp MZ-2500 HW.

Today I’ve gave a look at the Sony SMC-777 HW again. The system uses a “timed” bankswitch, presumably involving instruction pre-fetching.

For example (this is BIOS ROM code, located at 0x0000-0x3fff):

3BF3: 3E 10         ld   a,$10
3BF5: D3 1C         out  ($1C),a ;enables RAM bankswitch
3BF7: C7            rst  $00 ;executes this, then switches to RAM mode

Enabling this and adding the unimplemented features makes all of the available programs / games to boot properly with sketchy keyboard and some games with imperfect colors (presumably missing clut):