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Re: Possible Issue in ieeefp.h

On 11/21/2016 11:08 AM, Joel Sherrill wrote:

An RTEMS user has tried to build GNU FORTRAN. It used to build
and test OK. I am copying his report and my suggestion. I think
the constants tested in ieeefp.h do NOT match those predefined
by GCC. I need someone more knowledgable to confirm.



On Mon, Nov 21, 2016 at 9:24 AM, Ricardo Derbes <> wrote:
I'm trying to build rtems toolchain for i386 using
rtems-source-builder with fortran support (--with-fortran option).
The RSB I'm using has been dowloaded from git, commit
534332f22a66f16b4022e87ae50c11ff20c98dcb from Sep 12 2016.


As for my application I need fortran support, how can I fix this problem?
As long I can see, all symbols that the compiler claims as undeclared
are indeed declared and accessible in file
May be it's missing a symbol, e.g a proper value for LDBL_MANT_DIG ?

I see that GCC predefines these symbols:

#define __FLT_MANT_DIG__ 24
#define __DEC64_MANT_DIG__ 16
#define __LDBL_MANT_DIG__ 53
#define __DBL_MANT_DIG__ 53
#define __DEC32_MANT_DIG__ 7
#define __DEC128_MANT_DIG__ 34

And ieeefp.h in newlib has this:

#elif LDBL_MANT_DIG == 53
/* This happens when doubles are 32-bits and long doubles are 64-bits.  */
#define EXT_EXPBITS     11
#define EXT_FRACHBITS   20
#define EXT_FRACLBITS   32
#define __ieee_ext_field_type unsigned long

I am suspicious that the ifdef should use __LDBL_MANT_DIG__  not LDBL_MANT_DIG.

ieeefp.h is definitely intending to use LDBL_MANT_DIG. This is the C-standard defined name which is supposed to be defined in float.h, and which ieeefp.h directly states it is relying on. Apparently the float.h being used is not properly defined/set up, and this is what needs to be corrected.

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