[futurebasic] Re: Floating point question

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From: nerimic@...
Date: Thu, 23 Sep 1999 10:16:08 +0200
> I am a little confused about the format of floating point numbers in
FB^3.
>
> Are the floating point values defined with the "#" symbol extended
presision
> (10 bytes per number) or double presision (8 bytes per number)?

In PPC mode a variable dimensioned with # take 8 bytes (PPC numeric).
In 68K mode it  takes 10 bytes (SANE numeric).
A variable dimensioned AS DOUBLE takes 10 bytes in both PPC & 68K.

> Are single precision floating point numbers 4 bytes per number or 8 bytes
per
> number? This quote from the conversions manual seems to imply that they
are 8
> bytes but that seems wrong to me: "When saving single precision floats,
both
> PPC and SANE (but not FutureBASIC II) use the same 8 byte structure and
these
> may be saved as numeric values."

I think that it takes 4 bytes. Try this:
DIM a!
PRINT SIZEOF(a!)

> If floating point values defined with the "#" symbol are extended
precision
> with 10 bytes per number is it posible to convert them to the 8 byte per
> number double precision format? If not is it posible to still use the
> SaneCalls.INCL file from FB2 to convert between different kinds of
floating
> point numbers, even though the SaneCalls.INCL file seem to be written in
68K
> assembly? (I need the double precision numbers because they are required
in
> the format of a file my program creates for use by another program.)

DIM a as DOUBLE
DIM b#
b#=3.1415
a=b#
PRINT a

Michele.