[fpc-pascal] Bitcounting

Jonas Maebe jonas.maebe at elis.ugent.be
Sat Mar 5 23:24:27 CET 2016


On 05/03/16 23:12, Bart wrote:
> On 3/5/16, Jonas Maebe<jonas.maebe at elis.ugent.be>  wrote:
>
>> >FPC 3.x has system.popcnt
> Thanks.
> I see it's a compilerproc.
> How can I see how it'simplemented?

The "compilerproc" modifier does not influence code generation other 
than symbol mangling. You can just look at the implementation in the 
system unit like for any other routine.

It's however not just a compilerproc, but also an intrinsic. This means 
that the compiler knows about this routine, and may substitute it with 
more efficient code on some platforms. To know whether it does so in 
your case with your particular compiler version and compiler settings, 
you have to look at the generated assembler code.


Jonas



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