Amber ARM-compatible core

My local copy of Amber now boots RISC OS 3.

https://www.youtube.com/watch?v=jj3doUkCnV0

The LDMIA bug i raised today was the last bug i needed to fix to get RO3 to boot to the desktop properly. I also had to implement a translate flag via a wishbone tag and I had to implement data aborts. The data abort was almost implemented but didnt work because the cache write did not wait for external memory to acknowledge before doing the write to cache and acking the cpu.

If anyone wants a copy of my modified A23 sources they will shortly be getting published as one of the the MiST project cores.

I spent 4-5 months debugging issues in Amber and my cores and i eventually hacked up ArcEM to spit out an instrumentation stream that i could compare to a filtered/processed version of the amber.dis. Step by step i found where the two simulations diverged. There are still some differences but they are getting less and less.

Impressive stuff. Can't wait to see amber run zarch ...