Tansel,

the original Jazelle technology was just a small variation of the Thumb
idea: that with very little hardware you could accept a different
instruction set from memory as long as it was possible to translate
these one for one to the native 32 bit ARM instructions. In the case of
Thumb this was a specially designed 16 bit instruction set and for
Jazelle it was an interesting subset of the Java virtual machine. This
allowed things like "push instance variable 3" (in Squeak-speak) to be
executed directly at one clock per instruction while more complicated
things caused a trap which invoked a software implementation. It would
be possible to pervert this for Smalltalk but you would have to used the
same bytecodes as Java for the hardware translated subset.

The new Jazelle RCT technology (the original is now called Jazelle DBX)
is basically an addition of 12 new instructions to Thumb-2 to make that
instruction set a very attractive target for JITs. In particular it
allows zero overhead null pointer and invalid index checking. This would
benefit Squeak (think Exupery, for example) just as much as Java.

-- Jecel