Now you are onto something with the Transmeta CPUs.
Back in college I had a professor that updated the microcode on a Pentium III as part of his research. It has been about 10 years, but IIRC he change the processor mode that an instruction was available in. As you said it is a non-trivial exercise.
I'm wonder what the performance of a ARM core would be while emulating 68k code. If the performance is good enough it might be possible to use it to build a drop in replacement.
Of course now we are entering the world of the incredibly complex. A much simpler way would be to patch the ROMs to work around the offending instructions.
Back in college I had a professor that updated the microcode on a Pentium III as part of his research. It has been about 10 years, but IIRC he change the processor mode that an instruction was available in. As you said it is a non-trivial exercise.
I'm wonder what the performance of a ARM core would be while emulating 68k code. If the performance is good enough it might be possible to use it to build a drop in replacement.
Of course now we are entering the world of the incredibly complex. A much simpler way would be to patch the ROMs to work around the offending instructions.