23 Oct
2011
23 Oct
'11
7:51 p.m.
On 23 Oct 2011 at 21:32, David Riley wrote:
But if you're moving the decimal point around,
aren't you changing the
exponent? You're just doing it in base 10 instead of base 2. That's
why it's called floating-point - the point can move around.
I don't care if the radix is 2, 10 or 13. What is normally termed
"floating point" is a slight misnomer. If you will, a floating point
can move within the mantissa, but not outside of it. i.e. it can
have the position +/- logx(n), where n is the number of digits in
base x of the mantissa.
What's normally called "floating point" in the computerish sense,
allows the point to move far outside of the number of digits in the
mantissa.
Just a minor point (pun intended).
I'm sure that if you do much microcontroller or integer DSP work, you
use a lot of non-integer fixed point math in the form of scaled
integers.
It's interesting that while some vendors seem to be intent on
dropping decimal support on CPUs, there are others proposing decimal
co-processors-- and the POWER6 and 7 CPUs have always had decimal
floating point capabilities.
--Chuck