Re: [Simulavr-devel] Whats to do on execution of "illegal instruction"

[Joerg Wunsch]

As Petr Hluzín wrote:

> It *sometimes* works because simulavr code does not initialize the
> bytes in ALU registers (actually objects of RAM class).

Just like in the real CPU.

CPU registers and RAM contents are random, only IO registers
get well-defined state after a reset or power-on.

If someone is ambitious, every bit could be tracked whether it is
still in "X" state when being examined.  ISTR VMLAB does it that
way:

http://www.amctools.com/

Also, the usual HDL simulations track "X" bits.
-- 
cheers, Joerg               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/
Never trust an operating system you don't have sources for. ;-)