It executes all the code pertaining to the line in question.  So single-stepping
the line
   PORTB=0x0f;
actually executes the code:
   MOVLW .16
   MOVWF PORTB

and whatever else was that line was compiled into, like bank switching.

This is fine for debugging your C code.  If you have an insiduous compiler bug,
it won't help you, you'll have to find where the problem is occuring, single
step the ASM code, and send in a bug report to the company that makes the
compiler.

And this is a very good question.

-Adam

Lance Allen wrote:
>
> This is probably a dumb ass question.
>
> But how do you single step a programme with an ICE
> while trying to follow your C source code?
> I can with assembler, I cant see how this could be done
> with C if there is not always a direct correlation line for
> line, instruction by instruction.
>
> _____________________________
>
> Lance Allen
> Technical Officer
> Uni of Auckland
> Psych Dept
> New Zealand
>
> www.psych.auckland.ac.nz
>
> _____________________________