To prevent any misunderstanding.
Phoenix -> http://www.apollo-core.com/index.htm?page=releases
Phoenix is 100% 68000 compatible.
This means all code from the 68000 will run on it.
Phoenix support many 68020 and up instructions like 32bit mul, or 32bit Div or 32bit branch...
Phoenix also supports some new stuff.
For example there is a Chunky 2 Planar instruction
which converts 8 pixels in a single ASM instruction in 1 cycle.
Phoenix removes some addressing limits of older 68000-68060 Cores.
And Phoenix supports more registers...
To sum up:
Phoenix is fast - faster than 68060 in our tests.
Phoenix is in some ways easier to program than old 68k as some limitations are moved.
Phoenix has more registers which allows to easier implement some complex functions fast.
Phoenix has some new killer instructions which allow to do the work of many ( up to 100) old 68K instruction in a single instruction.
But of of today we do NOT guarantee 100% 68020 compatibility.
As a matter of fact right now no softcore does guarante this.
This means some 68020 will run some wont.
There might come out an upgrade which will fix this.
But for the early/first release - this is not guaranteed.