Re: Floating Point Support

["Dietmar Ernst" <erndie at gmx dot de>]

> Dietmar Ernst wrote:
> 
> >Hi,
> >
> >I am using newlib-1.10.0  for an AT91M55800A (ARM7 Core), my compiler is
> >gcc-3.2.1 for Cygwin. I've some problems when performing floating point
> >operations, for example "strtod". The conversion seems to work fine, but
> suddenly it
> >jumps to label "undfl" and leaves the functions with 0x0. There's not
> much
> >information available for this problem. Maybe it has something to do with
> >option "-msoft-float"?
> >
> >Dietmar
> >  
> >
> There has been no strtod problem like this that I am aware of.  Can you 
> give details of how you configured?
> 
> Some possible problems could be:
> 
>   1. You did not build gcc and newlib in the same build directory.  When 
> multilibs are involved,
>        it is best to build gcc and newlib in the same place.  When you 
> specify a compile with link,
>        gcc will link in the correct multilib.  Otherwise, you have to 
> manually specify which multilib
>       to link in and if you get it wrong, undefined behavior results 
> (e.g. mixing up little-endian and big-endian).
> 
>   2. Another possibility is that you have a compiler bug.  Is is 
> possible for you to try a different compiler?
>       If you still have problems with newlib, I suggest trying
> newlib-1.11.0
> 
> -- Jeff J.
> 

Normally, the selection of multilib works fine, e.g. in case of
ARM/Thumb/interwork.

Configuration of GCC:
$GCC_SRC/configure --target=arm-elf --prefix=$INSTALL \
--with-local-prefix=$INSTALL --with-gnu-as --with-gnu-ld \
--with-headers=$NEWLIB_SRC/newlib/libc/include --with-newlib \
--enable-multilib --enable-languages=c,c++

Configuration of newlib:
$NEWLIB_SRC/configure --target=arm-elf --prefix=$INSTALL --enable-multilib

Dietmar

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