C
Chris Dollin
Chris said:Not at all. I can do it with relative ease for a PowerPC. You get the
timing not from the source code
Well, it's not a C question then, is it; it's a question about how
some (particular) C code is compiled on some (particular) platform.
but you use a sim or an ICE on the
compiled system and can time between points be they HLL or Assembler. OR
even accesses to a memory location.
Measurement and calculation are not the same thing.
The problem only arises if you have an OS on the target that is
non-determinisitc.
Or if the target itself is non-deterministic, or at least you don't
have access to the source of the apparent non-determinism: I'm
thinking vaguely of the ARM on-chip cache.
Many systems run apps without an OS so their run times with and without
interrupts can be easily and repeatabley determined.
Sure:
If you pick the situations where it's easy, it's easy.
Some run with derterministic RTOS and again timings can be obtained...
Its how we do real time systems
Yes. You do them by /arranging that it's possible/; by doing things that
aren't about C, but about the environment the code runs in and is created
by.
It's important, so you have to do it; but it's not the general case
(just as PCs and workstations aren't the general case).