Re: Suddenly I need GMP and MPFR?

[David Daney <ddaney at avtrex dot com>]

Rick Mann wrote:
> On Apr 18, 2008, at 1:01 PM, Brian Dessent wrote:
>
> > See <http://gcc.gnu.org/gcc-4.3/changes.html>.  gcc 4.2.x only required
> > them if you enabled gfortran, but 4.3.0 and on require them
> > unconditionally.
>
>
> Thank you; I should've checked that first.
>
> I'm not sure I understand how GCC uses these libraries. If I'm 
> cross-compiling for AVR, shouldn't the library  be built on AVR? This 
> creates a new chicken-and-egg problem, doesn't it?

No, the libraries are only used by the compiler proper.  They allow the 
compiler to do constant folding at compile time and get the same answer 
that the processor would have gotten.

> If I build GMP/MPFR for Mac OS X using Xcode (assuming it'll even build; 
> apparently there are issues with Apple's GCC), that will build libraries 
> that execute on OS X/i386. Is that the only capacity in which GMP/MPFR 
> are used by GCC? 

Yes.


> Or does it attempt to generate target code that uses it?

No.