[Avrora] MSP430 / TelosB support for Avrora

[Roy Shea]

Hello Urs,

Great job getting the simulation for blink up and running on the MSP430!

> I think the MSP430 handles the carry bit differently from other
> architectures (at least for subtraction). I am still not sure how exactly it
> works, but by inverting the meaning for subtractions (sub, subc and cmp
> instructions) I got the simulation of the TinyOS Blink application to work.

With regards to the carry bit, take a look at the instruction summary
provided in the user guide for the subtraction operations:

http://focus.ti.com/lit/ug/slau049f/slau049f.pdf

There's a note describing the fact that the borrow used to set the carry
flag is treated as a .NOT so that:

Borrow yes -> Carry 0
Borrow no -> Carry 1

Does that clear things up?

Again, great job getting the MSP430 instruction set further along.

Peace,
-Roy