Lpc2000

Jaya,

OK - I give up. I've clearly failed to explain to you the point I was 
trying to make (which has nothing to do with interworking or whether 
or not particular features are supported by GCC). Maybe someone else 
can try.

Hopefully others will have understood what I've been trying to say, 
and it'll provide them some food for thought.

Brendan

--- In lpc2000@yahoogroups.com, "jayasooriah" <jayasooriah@...> wrote:
>
> Dear Brendan,
> 
> This dialog has gone long enough.  I like to finish off by 
addressing
> your lingering doubts once more as best as one can, and move on.
> 
> --- In lpc2000@yahoogroups.com, "brendanmurphy37" <brendan.murphy@>
> wrote:
> 
> > Consider the following sequence of events:
> > 
> > 1. We need some mechanism to lock out interrupts, for reasons 
that 
> > should be clear enough to everyone.
> > 
> > 2. We decide to implement this as in-line assembler, wrapped up 
in 
> > some nice macros. In fact, we implement exactly the same macros 
as 
> > you presented in your example.
> > 
> > 3. We test these out, and they work well. Everyone is delighted 
with 
> > the results. Our macros are a great sucess, and everyone is 
happy. 
> > Everyone uses them, all over the place.
> 
> Thus my on-the-fly example has served its purpose.
> 
> > 4. Then, as often happens, some new requirement comes along. Code 
> > space is now a real issue for everyone. No problem: our chosen 
> > architecture has just the solution: re-build all our software 
using 
> > Thumb mode.
> > 
> > 5. We re-build our software and are faced with an immediate 
problem: 
> > our nice macros that are used everywhere no longer work, as they 
use 
> > ARM-mode specific instructions.
> > 
> > How do we solve this problem? there are all sorts of ways it can 
be 
> > solved: I'm sure you and I could both come up with several 
without 
> > too much effort. The problem is that it will take effort, no 
matter 
> > how it's done.
> 
> You cannot turn off interrupts while in thumb mode if you do not
> interwork. 
> 
> > The point I'm making is that the more you use non-standard, 
compiler-
> > specfic features such as in-line assembler, the more likely it is 
> > that changing requirements will cause problems.
> 
> GCC supports interworking.  It has compiler options to select the
> paradigm you want to adopt for interworking.  If you do not want to
> use it because it is not supported in the same way on all compilers,
> that is up to you.
> 
> I like to use the feature given I think GCC supports it well enough.
> 
> > I completely take your point that your example was for 
illustrative 
> > purposes only, and that you probably wouldn't implement these 
macros 
> > in a working system (possibly for the reasons I outline).
> 
> This is not what I said.  I stand by what I said.
> 
> Finally Brendan, my on-the-fly example having served its purpose, 
and
> the forum having moved on, it is about time you do the same.
> 
> Jaya
>