ColdFusion CF4000 prototype Arrives!

[Piru]

The card will be assembled in the next two weeks and then the job of testing it begins.

This is the third ColdFusion prototype since the project was started way back in 2002

Well, be careful this one doesn't go up in a puff of smoke aswell... ;-)

I would suggest everyone to hold their horses for now. This is far from finished product.

[Piru]

@AmigaMance

Why does a 68k cpu has to emulate a 68k cpu?

Coldfire is not 68k CPU.

I have read that this is required for some fpu instructions only.

That's not the case.

Anyway, check out the thread about Elbox Dragon compatibility?, it has some discussion about the coldfire emulation issues. As you can see there isn't exactly full consensus about this matter, but as soon as (or if ever) some coldfire accelerator hits the market we will know for sure.

[Piru]

@Fransexy_

Sounds to me like a evolution of 68k CPU

Nope. It's completely new design, but it took the best aspects of m68k series (easy & logical asm programmability).

Keywords to look for: relationship, subset

It's no 68k CPU. Only later it added more m68k series compatibility, but it still is no m68k.

And about compatibility, again from freescale webpage:

You can find tools such as an automated 68K-to-ColdFire processor converter and an emulation library available

So, i think that you only need a library for compatibility not much more different of 040 and 060 accelerators in which you need a 68040.library to work

Wrong. This is automated *source-code* converter.
Emulation library allows you to run usermode code with performance hits (depends on the emulated insruction occurance rate).

And regardless, at supervisor level these CPUs are completely different. You must have full emulation or the board will not be able to run most games and demos.

Further, coldfire accelerator can't work with just something like 680x0.library. The system would never get to point where it could load the library from disk, the CPUs are too different. Basically the emulation would need to be available even before the system begins to execute the Kickstart ROM code.

[Piru]

So, i think that you only need a library for compatibility not much more different of 040 and 060 accelerators in which you need a 68040.library to work

And not much more different of the 64 bit risc AMD chips emulating x86 cisc instructions

Except that these AMD chips actually have full 32bit x86 emulation built-in, and that it is available at the moment the chip is powered up. As the x86 emulation is hardwired to the chip it doesn't involve any exceptions or performance loss. Even in 32bit x86 legacy mode these AMD chips kick serious behind.

Coldfire doesn't have such built-in emulation, and the software emulation involves slow exception traps.

[Piru]

@Oli_hd

Indeed, as more and more m68k instructions work without emulation Coldfire gets more feasible. Personally I'm a bit pessimistic about this, but maybe it'll work just fine.

However, how are you going to handle supervisor mode? My understanding is that supervisor mode is completely different in Coldfire, and to emulate m68k supervisor fully you'd need to pretty much have some full blown emulation for it (build compatible stackframes, emulate supervisor instructions etc).

[Piru]

@TheMagicM

A ODW Pegasos, while its a awesome machine, is $799. A A1 if one would want to purchase it probably cost the same or whatever (I dont know). If this board costs $300 or $400, plugs into your A1200 or A4k

ODW is full system. Plain Pegasos II motherboard + G4 is cheaper. If you assume that someone has A1200 or A4000, I assume the same someone has PC tower, keyboard, mouse, memory, HDD etc. ;-)

why even switch to a new system?

Because:
a) The new system is a lot faster (no legacy hw bogging it down).
b) With ColdFusion E-UAE is too slow to reach even A500 speeds.

[Piru]

Can't the instructions be converted on the fly when loaded from disk instead all the time when the program is running ? Kinda like an LoadSeg () patch or something

No, since you can't tell which part is code and which data. You'd end up corrupting some data in the process... bad.

there is already software that does this for the 060 IIRC (Cyberpatcher ? can't remember, never had an 060..).

Cyberpatcher doesn't do this. Nothing that wants to avoid random data corruption does this.

It would be MUCH faster:)

If it worked, but it can't.