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From: Ada novice <ycalleecharan@gmx.com>
Newsgroups: comp.lang.ada
Subject: Re: understanding floating point types
Date: Sun, 22 Aug 2010 03:37:35 -0700 (PDT)
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On Aug 22, 11:51=A0am, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:
> Compare:
>
> =A0 =A0type My_Float is digits 1;
>
> My_Float'Machine_Mantissa =3D 24 (32-bit IEEE 754 is used to model it)
> My_Float'Mantissa =3D 5 (=3D 4+1)
>
> =A0 =A0type My_Float is digits 2;
>
> My_Float'Machine_Mantissa =3D 24 (32-bit IEEE 754 is used to model it)
> My_Float'Mantissa =3D 8 (=3D 7+1)

Thanks. The Float'Machine_Mantissa remains constant in your examples
with 1 and 2 precision digits. Is the Float'Machine_Mantissa a
predefined value that is constant for any precision digit requested?

I have a second query: Say we consider the type My_Float is digits 2.
This means that between the model numbers, the resolution is 1/(2^8)
with the 8 in the expression obtained as 4 X 2. Am I right? Now if we
have to multiply two numbers: say a =3D 2.33 and b =3D 3.45. Does Ada
first convert each operation to its nearest model number and then do
the multiplication and represent the result to its nearest model
number? Or does Ada do the multiplication first and then represent the
result to to its nearest model number?


Thanks
YC