Hey, guys.
If there is still an interest in simulator for Atmel AVR 8-bits MCUs,
I'd like to suggest one: MCUSim (
https://github.com/dsalychev/mcusim). It's
programmed in ANSI C under New BSD license and still in development, but
instruction set interpretator, MCU initialization, basic timers for ATmega8A,
GDB RSP interface and VCD dumps are there.
Personally, I compiled it under macOS, FreeBSD, NetBSD and
elementary OS (GNU/Linux) succsessfully. I'm working on this small project
(
https://github.com/dsalychev/xling/blob/master/hardware/images/xling-0.1.12-render.png)
and using simulator to track any mistakes in two-wire interface of LCD display.
I'm spending my spare time on design and programming, and if you're
ready to help or suggest anything, please, feel free to ask.