[fpc-devel] General Decimal Arithmetic

[john at johneb47.id.au]

On Mon, Jan 28, 2008 at 12:53:26PM +0100, mm wrote:
> Vincent Snijders a écrit :
>> john at johneb47.id.au schreef:
>>>    2. Are these operations presently available within Free Pascal?
>>
>> AFAIK, not distributed and installed by default with Free Pascal. There 
>> are a number of arbitrary precision libs around, for example bigint from:
>> http://www.polarhome.com/~franco
>
> Regarding big floats, I know only two libraries, the one of Wolfgang
> Ehrhardt:
> http://home.netsurf.de/wolfgang.ehrhardt/mp_intro.html
> and mine:
> http://www.ellipsa.net/public/nx/
>
> But they don't follow IEEE standards. With multiprecision numbers, this
> is not always possible and, overall, it would be a small disaster for
> the running times. For instance, correctly implementing the "Inexact"
> error as described in the IEEE standard increases the code size and
> slows down computations for a questionable usefulness [*] (with floating
> point numbers, what is exceptional is not an inexact result but an exact
> one). Even the subnormal numbers are not really necessary (the only
> benefit is that, with them, we always have ((A-B = 0) <-> (A = B))).
>
> [*] Of course, in case of a fixed (small) precision decimal library,
> like the one of the OP, it might be necessary. "Decimal" libraries are
> mainly aimed at financial computations.
>

I have investigated the above links and it would appear that I would be 
duplicating the efforts of others for very little (if any) gain.
For my self interest will study the code in these libraries and thank you
those who responded.

Regards

John