23 Oct
2011
23 Oct
'11
6:04 p.m.
On 23 Oct 2011 at 19:54, Toby Thain wrote:
I was talking about fixed point, which is why I wrote
"fixed point".
The contextual examples are Fred's pennies or SQL's DECIMAL.
Regardless, I was referring to the old, almost forgotten "floating
decimal point" sometimes found on old calculators and in early
computer programs. There, the point moves anywhere within the
significand, but not outside of it.
For example, if you have a 4 digit device, a floating point can
express values between .0001 and 9999. No exponent to extend the
range of absolute values. Fixed point, in the same sense only means
that the decimal point is anchored to a particular position; e.g.,
12.34 is a fixed-point number with the point fixed between the two
high-order digits and the two low-order digits.
It's a shame that just about all the web has on "floating point" is
about exponential/scientifc notation, which is not strictly the same--
including the screwball notion that "fixed point" somehow means
"integer".
--Chuck