Coldfire status

[Munchkin]

I've lost track a bit the last year so I'm just wondering what the status is on the different Coldfire projects.

Are any of them progressing, will it be possible to just plug one in when it's finished and continue as before running the 68k software?

I'd appreciate some info about this or if the projects have died.

This is for my A4000D. I know there seemingly is one on the way for the 1200 but since I don't own a 1200.. well.

[motorollin]

Have a look at the thread I posted about Coldfire compatibility. Looks like there are some essential missing instructions in the Coldfire CPU which means 68k compatibility won't be possible without emulation (=UAE) :-(

--
moto

[Munchkin]

Ok, I see. But how would that impact performance?

[motorollin]

Well, I suppose a lot of stuff wouldn't need to be emulated (i.e. custom chips). But emulating a 68k processor on a 266MHz CPU probably wouldn't be much fun, and also may not work for non OS-friendly software.

--
moto

[Munchkin]

Oh well...

Just have to do "surgery" on my CS MkII and hope that one of the 060's I got hold of are in working order then to get the best possible speed out of it..
 

[SamuraiCrow]

I doubt the Coldfire-based projects will arrive sooner than the PowerPC-based projects (such as PowerVixxen).  Furthermore, since you'd have to run EUAE anyway on a Coldfire, you'd probably get better performance on a PowerPC box anyway.

[Doobrey]

motorollin wrote:
 Looks like there are some essential missing instructions in the Coldfire CPU which means 68k compatibility won't be possible without emulation (=UAE) :-(

Not necessarily.
If the missing instructions can be caught with the illegal instruction trap then only those instructions will have to be emulated (just like the 040/060 libs do for the missing FPU instructions)
 The real bugger will be if there's any instructions that aren't 100% identical in use to the 68k versions.

[CRL]

Hi all-
Hmmm.. there is a lot of negativity here.  I just revisited the Dragon FAQ site and it seemed as tho they expect the Dragon to run "most" 68K software straight up, no emulation.  As I understand it, the latest coldfire has enough of the 68K series (what? commands? microinstructions? complex instructions?)functionality that a relatively minor patch will supply the rest and let the thing run transparently as a 68K CPU with FPU, MMU, etc.

Of course, if it was all that easy they would have released the thing in Jan 05/ er Jul05/ er Oct05/ by Dec 05/ any day now.

I can believe things go wrong and make deadlines slip- but I'm really hoping the Dragon will run my old software at semi-modern speeds.
CRL :-)

[CRL]

sorry- double post
CRL

[Piru]

Dragon FAQ written by who?

[amigagr]

Piru wrote:
Dragon FAQ written by who?

ahh, seams that it was satan (elbox) by him self  :crazy:

[Piru]

@amije

Nah, but if you were to market something, would you highlight the obvious defects in your product, or try to downplay them?

Elbox also has some nice habit of using theoretical values out of context in their marketing material. For example the "266MB/s transfer speed" of the Mediator (PCI vs PCI speed is irrelevant with mediator, as the bus between the system and the pci-subsystem is ridiculously slow, and surprisingly this more important speed is not mentioned anywhere...).

[amigagr]

just hide them under the carpet :-)

[boing]

Piru can you please clarify your statement?

Also the speed of the ColdFire running 6K code is easily answered by looking that the instructions, addressing modes and registers offered by by both the 68000-68060 and and Specific ColdFire chip used by Elbox (or other company).

In fact I'm sure Moto/FreeScale has a comparison chart buried somewhere on their site.

[jdiffend]

Ok, do a search and you'll find this discussed by several people in depth in several old threads.  The oldest ones probably aren't around anymore (1990ish?) but to summarize:

The Coldfire CPU is missing some 68K instructions, some are there but act differently than the 68K equivalent and the coldfires currently have some additional hardware built in that must be configured on startup so it doesn't conflict with existing Amiga hardware.  It also wasn't as feasible on older Coldfire cores due to a few missing instructions.

There are ways around all the software problems, but to do this would require a new Amiga exec.library since it executes illegal (on the coldfire) instructions early in the startup code.  It's so early that it crashes before it could even transfer to an expansion ROM (actually, it happens *while* it's checking for one).

FWIW, *IF* someone could get past the exec issue it would be the fastest 68K Amiga any of us are likely to see even with the illegal instruction traps.  Oh yeah, the latest Amiga ROMs are FULL and the instruction traps require some space.
I also think a couple other devices might need to be native Coldfire code due to the close tie in with the exec. (timer.device?)

I actually gave a commented disassembly of the latest exec to a guy (he gave me the raw disassembly and I commented it) with a V2 Coldfire dev board over a year ago and he was going to port it but I don't know how far he got.  Actually, I think it was 2 years ago that Freescale gave away the dev boards so it's been even longer than that.

If someone had access to the Amiga ROM sources this wouldn't be a bad project.  Without that you have to reverse engineer things, fix them, etc...