Home Page Forums MAME MAME NEC PC-8801 Phoenix WIP

Ok, it's not a secret that I'm currently rewriting NEC PC-8801 HW driver because old driver was too rotten to work on it without going nuts.

NEC PC-8801 is arguably the most popular JP computer in Japan, and indeed it's the JP computer machine with most dumped games.
This list surely hides a lot of sleeper games that only deserve to be discovered by us

Anyway, current rewrite status (r10017) is that it loads the N88-BASIC and resets itself when it's time to give control to the user, probably because banking is still sketchy as per now.

Best PC-88 RPG is Undine:

http://www.activegamers.com/soft/undine/undine88.htm

It's the maker's official homepage, they let you download their old games for free: http://www.activegamers.com/pc88/d88/undine.lzh

Why did you drop PC-8801mk2sr emulation?
PC-8801mk2sr was well emulated in the previous versions.

aabbcc: do you read English?



In other words, we were unable to find and fix bugs in the support as it existed (and the author is long gone) so it got nuked and is being rewritten in a much cleaner fashion.

RB, I do know that. But, when I do

mess pc8801mk2sr

mess prints

"pc8801mk2sr" approximately matches the following
supported systems (best match first):

pc8801mk2 PC-8801mkII
pc8801mk2fr PC-8801mkIIFR
pc8801mk2mr PC-8801mkIIMR
pc8801 PC-8801
pc8801mh PC-8801MH
pc8801ma PC-8801MA
pc8801ma2 PC-8801MA2
pc8801mc PC-8801MC
pc8801fa PC-8801FA
pc88va PC-88VA

So, pc8801mk2sr driver was completely deleted.
Hence I wrote 'Why did you drop PC-8801mk2sr emulation?'

That set was basically an hack based off another identical romset with different resolution hooked up. The driver was SO bad that it didn't supported dynamic res in the driver.

And, just for the sake of let devs people point the finger against the old driver ... ok, MAME memory system is usually criticized performance wise and blah blah blah, but I really CAN'T expect a dual z80 system that was getting a variable emulation speed from 500% to ... 7%~9% on my i5 (generally worse than Naomi driver!). fwiw the same bench game (Tokyo Nampa Street) gets a steady 1200% on my Sharp X1 driver, and that driver could be improved too performance wise.



Looks cool, will keep an eye on it

After implementing window offset bank it now loads and executes N88-BASIC properly. Window offset banking is just a byte register located at i/o 0x70 (r/w, another register at 0x78 does auto-inc) on which you can check what Work RAM window should appear at 0x8000 - 0x83ff, it's mainly used in N88-Basic mode only to circumvent the 32k RAM limitation. Don't want to repeat myself, but that's simple to implement IF you write custom code like I'm doing at current time.

It also seem that we can load some games too, will try now to see if they can do anything meaningful once that we hook-up proper 0xc000 - 0xffff ALU/VRAM bankswitching.

Lots of missing features, but hey

EDIT: kind of amusing, Z Gundam seems playable, although with text layer garbage.

Not bad for 2 days from scratch

Don't have much time in these days, but managed to fix the layer masking.

Z Gundam is fully playable as per now with a minor layer clearance bug if you don't enter into gameplay asap, other games have more or less issues, main reason is that irq support is basically non-existant (I need to understand how i8214 really works, if Curt wants to check it out be my guest ).