Hi Jörg,
does anybody know, what's happen, if a real controller get a invalid
opcode? As the SBRS code in case of FF FF suggest sould this mean, that
the decoding logic in avr isn't complete so that nobody knows, which bit
- that's for example described as 0 or 1 - in reality is interpreted as
X. Right?
I remember the Z80 days. It had also some undocumented opcodes. And some
are sometimes used. Like now for FF FF in avr. On Z80 it was easy to get
a single step mode. I think here it's only possible with JTAG debugging.
To answer Klaus question - my proposal in this case would be: (like
Albrecht suggest) let the behaviour (abort as now or maybe breakpoint in
case of invalid opcode and emit a error message) as it is but with a
commandline option, that change the behaviour for FF FF to NOP (or maybe
the SBRS action) WITHOUT any message.
Maybe: "--invalid-opcode=(ffnop|break|abort)"
ffnop - FF FF interpreted as NOP without any message
break - behaviour like breakpoint with message
abort - (the default) abort simulation with a message
cu, Thomas
_______________________________________________
Simulavr-devel mailing list
Simulavr-devel@nongnu.org
https://lists.nongnu.org/mailman/listinfo/simulavr-devel
