> An even better answer is to specify the amount of *time* to waste.
Let the
> assembler calculate how many instruction cycles that is, then
calclulate the
> least number of instructions to take that many cycles.  But there's
another
> wrinkle.  Often you need two instructions to be a fixed minimum time
apart,
> but you have other things you can do during those instructions
although they
> don't guarantee taking that minimum amount of time.  So you want a
minimum
> guaranteed delay in time, but are going to spend some of that with a
fixed
> number of instruction cycles.  Therefore what you really need is a way
of
> saying, for example, "Take 2uS, but I've already used 5 instruction
cycles
> out of that 2uS.".  This shows the part you know about and can control
in
> the source code without any implicit reliance on the processor clock
speed.

One step better, and one level up in the language picking order: I'd
like to specify that, and not have to worry about how many instructions
I spent doing those other things. And I want to be able to specify that
in loops too. Does anyone know of a HLL syntax (or even an
implementation) for this?

Like:

   timing_start;
   for( i = 0; i <= 8; i ++ ){
      timing_interval( 1.0 / 115200 );
      outpin = data : 0;
      data = data >> 1;
   }
   timing_interval( 1.0 / 115200 );
   outpin = 1;
   timing_interval( 2.0 / 115200 );      

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu
 

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist