Re: [avr32-libc-devel] Summary of functions in newlib'slibmandfloating point support in AVR32

[Gupta, U. <Ush...@at...>]

> > >From the above, it looks like the default library version would be
> IEEE.
> > Can you verify this? Remember that we're using a patched Newlib 
> > 1.16.0, not the latest version of Newlib. If we are using the IEEE 
> > version by default, then this would simplify implementation of the 
> > math library for avr32-libc.

Does math library for avr32-libc need to be multi-standard compliant as Newlib??

> > > The versions of the library differ only in how errors are handled.

This webpage gives information on Standards Compliance. Table E-1(Exceptional cases and libm functions) shows the exceptional input values for libm functions and their return values under different standards.

http://docs.sun.com/source/806-3568/ncg_compliance.html

This is how Newlib also handles exceptional input values.



> -----Original Message-----
> From: Gupta, Usha [mailto:Ush...@at...]
> Sent: Tuesday, July 27, 2010 12:36 PM
> To: Weddington, Eric; usha gupta; avr...@li...
> Cc: Mainchain, Stephane
> Subject: Re: [avr32-libc-devel] Summary of functions in
> newlib'slibmandfloating point support in AVR32
> 
> 
> 
> > -----Original Message-----
> > From: Weddington, Eric [mailto:Eri...@at...]
> > Sent: Tuesday, July 27, 2010 2:51 AM
> > To: usha gupta; avr...@li...
> > Cc: Mainchain, Stephane
> > Subject: Re: [avr32-libc-devel] Summary of functions in newlib's
> > libmandfloating point support in AVR32
> >
> >
> >
> >
> > > -----Original Message-----
> > > From: usha gupta [mailto:ush...@gm...]
> > > Sent: Monday, July 26, 2010 6:24 AM
> > > To: avr...@li...
> > > Subject: [avr32-libc-devel] Summary of functions in newlib's
> > > libm andfloating point support in AVR32
> > >
> > > Hi All,
> > >
> > > I have been investigating newlib's libm and floating point
> > > support in AVR32 .Here is the information that i have got so
> > > far. I would like to discuss on implementation of libm for
> > > avr32-libc.
> > >
> >
> > <snip>
> >
> > > Newlib's libm
> > >
> > >
> > >
> > > There are four different versions of the math library
> > > routines: IEEE, POSIX, X/Open, or SVID.  The version may be
> > > selected at runtime by setting the global variable
> > > {_LIB_VERSION}, defined in {math.h}.  It may be set to one of
> > > the following constants defined in {math.h}: {_IEEE_},
> > > {_POSIX_}, {_XOPEN_}, or {_SVID_}.
> > >
> > > The versions of the library differ only in how errors are handled.
> > >
> > > Default version is X/Open.
> > >
> >
> > I see that you got the above information from the Newlib manual (recent
> > version online). However, compare that to what is found in the actual
> > math.h that is being used for the AVR32:
> >
> > ============================================
> >
> > /* Global control over fdlibm error handling.  */
> >
> > enum __fdlibm_version
> > {
> >   __fdlibm_ieee = -1,
> >   __fdlibm_svid,
> >   __fdlibm_xopen,
> >   __fdlibm_posix
> > };
> >
> > #define _LIB_VERSION_TYPE enum __fdlibm_version
> > #define _LIB_VERSION __fdlib_version
> >
> > extern __IMPORT _LIB_VERSION_TYPE _LIB_VERSION;
> 
> 
> > #define _IEEE_  __fdlibm_ieee
> > #define _SVID_  __fdlibm_svid
> > #define _XOPEN_ __fdlibm_xopen
> > #define _POSIX_ __fdlibm_posix
> >
> > ============================================
> >
> > >From the above, it looks like the default library version would be
> IEEE.
> > Can you verify this? Remember that we're using a patched Newlib 1.16.0,
> > not the latest version of Newlib. If we are using the IEEE version by
> > default, then this would simplify implementation of the math library for
> > avr32-libc.
> 
> Looking at file "newlib-1.16.0/newlib/libm/common/s_lib_ver.c", the
> default is _IEEE_ but it includes fdlibm.h which defines _XOPEN_MODE which
> makes _XOPEN_ as default.
> 
> ==========================================================================
> ==
> /*s_lib_ver.c*/
> 
> #include "fdlibm.h"
> 
> /*
>  * define and initialize _LIB_VERSION
>  */
> #ifdef _POSIX_MODE
> _LIB_VERSION_TYPE _LIB_VERSION = _POSIX_;
> #else
> #ifdef _XOPEN_MODE
> _LIB_VERSION_TYPE _LIB_VERSION = _XOPEN_;
> #else
> #ifdef _SVID3_MODE
> _LIB_VERSION_TYPE _LIB_VERSION = _SVID_;
> #else                                   /* default _IEEE_MODE */
> _LIB_VERSION_TYPE _LIB_VERSION = _IEEE_;
> #endif
> #endif
> #endif
> ==========================================================================
> ==
> ==========================================================================
> ==
> /* fdlibm.h*/
> /* REDHAT LOCAL: Default to XOPEN_MODE.  */
> #define _XOPEN_MODE
> ==========================================================================
> ==
> 
> All the functions in Newlib's libm includes "fdlibm.h". I have verified in
> the patched version of Newlib for avr32.
> 
> --------------------------------------------------------------------------
> ----
> The Palm PDK Hot Apps Program offers developers who use the
> Plug-In Development Kit to bring their C/C++ apps to Palm for a share
> of $1 Million in cash or HP Products. Visit us here for more details:
> http://ad.doubleclick.net/clk;226879339;13503038;l?
> http://clk.atdmt.com/CRS/go/247765532/direct/01/
> _______________________________________________
> avr32-libc-devel mailing list
> avr...@li...
> https://lists.sourceforge.net/lists/listinfo/avr32-libc-devel