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

[Klaus]

Hi,


> > simulavr is a tool from programmers for programmers. If someone need
> > for a debug session a
>
> one remark: "for programmers" is right. But this means then, that one
> have to visit the code, understand the code and find out, where to
> change. Not to make in 5 minutes for somebody, who's not familar with
> the code. And if you are in a hurry ... :-)

The opposite is to understand a more or less complex config file. As you 
see from the mailing list from the last 3 days what is happen:

Someone find simulavr on a non official git repo. Someone try to install 
without reading the installation guide. Someone was not aware what is 
bootstrap and have no idea how to access a git repo from savanah. Next 
step was loading a bootloader and starting the code with wrong start 
address. OK. All this is quite normal. Everybody wants to solve the own 
problems and not start reading. The tools simply should work and exactly 
in that fashion someone expects. Do you believe that these people read a 
configuration file handbook?

If I inspect some source code I simply use tag files and grep to find 
what I can do. The actual problem can be solved by simply grepping for 
"illegal instruction". This points you to the decoder.cpp. 2 minutes 
later you can hack that file. If not, it is quite hard to develop a 
controller chip where you can not look into and only have these very 
clear and simple data sheets :-)

And yes, that is something we can support. I currently have no idea how 
to break on a instruction for gdb. And is it save to simply decrement 
the PC to step in place? Maybe we can write a "hacked" special 
instruction for users there.

But adding a much more complex config file is not a solution for a 
convenience problem. The underplaying problem was a forgotten 
$pc=0x7e00. I believe that this single line is nothing against a config 
file which allows setting breakpoints, nop, sbrs and other instruction 
options for each individual instruction. And yes, there are some more 
options like "resetting core" on special memory access and so on...

What was the idea behind the scripting interface for tcl, python and all 
other languages which is supported out of the box from swig and is also 
supported by our autotools build toolchain... :-) I expect that some 
problems can be solved within 2 lines of tcl or python code... But users 
must start reading the docs....

Regards
 Klaus