The amiga is a multitasking computer, so why not use 2 coldfires, running separate tasks, while one chip is trapping and emulating code, the other coldfire continues running it's task, hiding the speed penalty that emulation brings.
Running two "normal" applications on two Coldfire CPUs (like SMP) does not work.
For this cache coherency (bus snooping) is required.
The Coldfire does not do bus snooping.
The 68040 and 68060 were supporting bus snooping.
You could create great working multi processor systems out of 68040 and 68060 but not out of Coldfire.
Lets be clear here.
The Coldfire has some advantages:
1st)
Freescale has the Coldfire set up to work like LEGO.
You can easily put together parts, as you please.
If you look at the Freescale side you will see that there are dozens of different Coldfire CPUs put together.
This somewhat shows how simple it is to put new Coldfires together.
This LEGO feature is what makes the Coldfire interesting as the key for the AMIGA is to get something like SuperAGA into the Chip quickly.
Compared the classic AMIGAs the Coldfire is quite fast.
Yes, there are other higher clocked CPUs available but
the Coldfire V5 runs with 400 MHz and has about the same performance as a 68060 clocked with 400MHz.
So for a slim AMIGA OS system a 400 MHz Coldfire / 400Mhz 68060 does fly.
The only situation where you would want more Power is for something like Video encoding. As you might know the Coldfire has a MAC unit which is about something like ALTIVEC for the poor. The MAC Unit helps to accelerate stuff like FF transformations quite good.
So for tasks like Video encoding the Coldfire has more power than a 68060 400MHz would have.
Another option which will fit perfectly into the AMIGA spirit is putting a dedicated unit on this tasks. Freescale offers DSP cores which will be perfect for doing video encoding. Freescale could without any problem put SuperAGA, a 400Mhz Coldfire and a 400Mhz DSP into one chip.
The resulting chip will be relative small (read: cheap),
will be quick to produce, and it will be powerful enough to let AMIGA OS fly.
The DSP could be nicely integrated into AMIGA OS.
Think of it as a 2nd Copper aka a SuperCopper.
The DSP could be used to play video and audio Datatypes.
The SuperAGA chipset already includes DMA engines for stuff like YUV conversion. The idea to upgrade this with a powerfull SuperCopper that would be specialized for the heavy lifting needed for Video encoding, makes good sense.
We were thinking about designing our own mini-DSP for this - but as Freescale has powerful DSP cores in their LEGO toy box it might be clever to just take an existing DSP which has already a wealth of datatypes for audio and video developed for.
This is what makes sense to me.
Please mind the target is not to create a CPU which is faster than a 8-way Opteron or CELL.
The goal is to create a CPU which is not expensive, which runs passiv and which is fast enough to let AMIGA OS fly.
The big advantage of the AMIGA OS system is the elegant design and the resulting low memory and speed requirements of it.
There is a market for AMIGA OS for a small system.
You can think of it as a Amiga-Joystick, AMIGA smartphone or AMIGA-Wii.
There is no market for a Desktop system anymore.
The Desktop area is fully saturated with Windows,Apple and now even Linux.
If you want to build a new high end system take x86 and Linux.
I believe that the future (if any) for AMIGA OS is to power a sub $100 device.
And for this target market the Coldfire is a quite sensible choice.
AMIAG OS needs again something like a A500.
Low price but powerful for its size and price.
