convert mpf t to double with rounding-modes defined by ieee754

Décio Luiz Gazzoni Filho decio at
Mon Aug 1 10:11:32 CEST 2005

On Aug 1, 2005, at 5:02 AM, usenett at wrote:

>>> I want to write a function of converting mpf_t-variables to  
>>> doubles by a
>>> given rounding mode (to-nearest, truncation, plus infinity, minus
>> infinity)
>>> defined by the IEEE754 standard.
>> See:
>> Conversion from mpf_t to mpfr_t is very straightforward.
> Thanks for the link, but thats not really what I'm looking for. I'd  
> like to
> know 'how' to convert a binary number to a correctly rouned double  
> float to
> implement this directly for the GMP-library without using the  
> inefficient
> indirection with MPFR.
> Isn't there any good tutorial how to do such things?

Why not use mpfr_t throughout, without making any conversions?

Or are you implying that MPFR is inefficient?

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