Re: Is an RTOS Required for Ada?

["Tarjei Tj�stheim Jensen" <tarjei@online.no>]

Larry Kilgallen wrote:

> Tarjei Tj�stheim Jensen writes:
> >
> > Robert Dewar wrote
> >>For example, in GNORT mode, the compiler will generate an open
> >>loop for a block copy, to avoid calling the bcopy routine in
> >>the run-time
> >
> >
> > I'm rather surprised. I would assume that the most eficient way of doin this
> > would be to use inline assembly code. I thought most cpus have a nice set of
> > special instructions that will do this. Could there be problems with using
> > these instructions?
>
> Those with great concern for speed will often be using RISC machines,
> where instruction sets have been simplified.  Presuming reasonable
> caching inside the CPU, data loads and stores will dominate the
> copy time.
>

My question was rather clumsily put: My surprise was that gnat used bcopy instead of generating the
instructions. It seems to be overkill to call a function instead of just emitting the assembly
instructions.

I seem to remember that function calls are supposed to eat clock cycles and should if possible be avoided.
Especially in cases like this where I assume (I've not checked this so I may be horribly wrong) this is a
frequent function call. It is hard to imagine the function call being any saving in either time or space
over emitting the code inline.


 Greetings,