GP32 Which Amstrad Emu Should I Go For?

[rackbox]

Though I have just begun my journey into the world of programming the GP32 I have clear goal, that is to make a good Amstrad CPC emulator for this little toy.

Now I need to know (even if I can't use the information yet) which PC-based emu is the fastest and most compatible and has available source code.

Perhaps I shoot too high, but at least i shoot ;-)

 

[don]

http://arnold.emuunlim.com/

Arnold is some quite portable and open CPC emulator.

 

[xenon_soft]

I think Arnold is a good idea, also because ARNOLD is a CPC+ emulator, so we can play Burnin' Rubber and cardtige into our gp32. I am an Amstrad CPC 464+ and GX4000 user and I like very much its games.

Yours,

 

[rackbox]

It seems rlyeh has already made some work with arnold - don't know how far he is, but perhaps someone knows where he's got the source, so someone can optimize it...

 

[DaveC]

It seems rlyeh has already made some work with arnold - don't know how far he is, but perhaps someone knows where he's got the source, so someone can optimize it...

Hey, OMARMD surprised to see you here, good luck with the CPC emu.

 

[Octoate]

I think Arnold would be the best emulator to port. Maybe you can have a look at the Linux version by Nurgle (http://arnold.berlios.de) since it uses SDL.
The only problem - I see - is that Arnold isn't the fastest emulator around, so you will need a lot of optimization. I am sure that Kevin Thacker can help you, so just drop him a mail.

 

[Antiriad]

Rackbox

The sources of Arnolds two versions are available to download from both the aforementioned websites. And in regards to the Linux version, SDL has been ported to the GP32 and is downloadable from Sourceforge.net

But as you may have heard, Arnold is not necessarily the fastest CPC emulator out there as the current beta of fCPC32 (which its based upon) does need plenty of optimisation for speed. I personally have some concerns about whether the GP32 can run it adequately, but then again its author Kevin Thacker was considering doing a port to the GBA (!) last year so perhaps Im wrong.

Saying that, theres been no word about it since, but this could be due to constraints on time rather than hardware. Kevin, who is contactable via the Arnold website is a busy but helpful chap who will be happy to answer your questions as hes always got back to mine eventually.

As for the alternatives let see...CPCemu's Linux port also uses SDL and whilst its sources aren't freely available its author Rainer Loritz did at one point express a willingness to release them for a port to the GP32 although he's gone quiet on me.

More hopeful is Ulrich Doewich author of Caprice who said he would be ready to supply the source to whomever was interested in porting it. Im not sure whether this would need any less optimisation than Arnold mind. Well worth getting in contact with in my books.

Probably the fastest CPC emulator is No$Cpc but as with CPCe is likely to be 100% 80X86 assembler not allowing ports to machines with other CPUs. Arnimedes is another which might be in the same boat.

WinApe is another one, but its sources are not available and its author never got back to me. Still you could always try.

 

[rackbox]

Yeah.. Saw all the other EMU's and couldn't be able to locate sources for them. Also in my humble opinion CPE seems not too demanding, though in it's "fast" versions it doesn't support many of the nice undocumented tweaks, that Amstrad was able of.

I took a crack at Arnold's source, and (surprise) IT'S HUGE!! Bigger than I first imagined with a program which at compiled size is only 255K or so...

It runs 100% on my CPU (1.3 Ghz Pentium M) so perhaps optimization is in deed in order..

So don't get your hopes up just yet.

Well.. Perhaps I'll take another approach. If I can find a good useful Z80a processor emulator which is easy to implement in an emulator that I make myself, there is a chance. It should be pretty easy (though time comsuming) to implement Amstrad's various jumpblocks and memoryhandling, being that the machine is rather predictable and seems to have an easy RAM setup.

Anyone got some ideas for the project?

I know, that I really am not the super coder just yet on GP32, but at least I got 2 simple progs up and running yesterday after beginning my "journey". So in time, my friends, in time ;-)

Rackbox

 

[Octoate]

Well, if you are thinking about programming a new CPC emulator then you should have a look at CPC4x (this URL currently don't work for me, so you can download a copy from Zophar's Domain). It's a CPC emulator for X11 which was in very early stages (at that time I implemented Mode 0 into it ) and uses Marat Fayzullin's Z80 core.
Since it is easy to understand it surely would be a good point to start with.

 

[Antiriad]

Z80 emulation..perhaps it would be worth trying to contact the authors of the Speccy emulators for the GP32?

By the same logic, would Skeezix Castaway sources be useful for the sound? After all the CPC and the ST had very similiar Yamaha sound chips.

 

[Octoate]

The YM2149 (Atari ST) and the AY-3-8910 (CPC / Spectrum, ...) are the same chips. They were just manufactured by different companies. The YM is from Yamaha and the AY by General Instruments.
More information about this soundchips on bulba.at.kz.

 

[Antiriad]

Well the Genesis8 seems to be a good place to look for all the CPC emulators and any available sources. Its got CPE's source files there and some pretty obscure CPC emulators that Ive never heard of before.

Rackbox, might be well worth you perusing the Unix/Linux ones such as CPC++, CPC4X and XCPC.

Ive got to be honest and state that personally whilst its great to be able to emulate the CPC Plus, i dont view it as an essential considering its very small software library. Id be much happier with a CPC emulator for the GP32 that got all the basics done right.

 

[rackbox]

Oh.. And Amstrad has a MODE 2 at 480x200 px in 2 colors.. Is there a smart way to overcome this on the 320x240 screen?

 

[Octoate]

640x200 with 2 colors

I think the only way to use this resolution is resizing the screen. This won't look perfect, but it would be ok.
For fast resizing you can just draw every second line...

 

[Antiriad]

Rackbox, i forgot one more potential emulator: CPC-em this is a Dos/Windows based one with its sources downloadable.

I assume you have the CPE sources by now? If not, its here

 

[Octoate]

CPE was indeed a nice emulator but it was written completely in assembler. Caprice would be more interesting, since it is a redesign of the CPE emulator (where Ulrich Doewich submitted some parts). AFAIK Caprice is now fully written in C, but I am not sure where I heard that...

CPC-em is a nice emulator, too. The con is that it's in an early stage. I am not sure if it is able to emulate the newer games or demos...

 

[*Dc*hardcoregamez]

BRING THE AMSTRAD!

 

[Antiriad]

Quite true Octoate. It is written in Assembler, so perhaps as you say Caprice is the next best bet.

So to sum up, it would seem that its down to the Windows/Dos emus Arnold, CPC-em and Caprice which youll need to email Ulrich Doewich about. (WinApe and CPCEmu too but again authors need contacting)

Then theres the Unix/Linux ones CPC++, CPC4X and XCPC as an alternative, but their source availability is unknown.