Re: Floating Point Approximations.
Date: Thu, 29 Mar 2007 13:02:53 GMT
David Cressey wrote:
> "paul c" <toledobythesea_at_oohay.ac> wrote in message
>>Bob Badour wrote: >> >>>David Cressey wrote: >>> ...
> Likewise the programmer who uses Oracle math for amortization calculations.
> Regardless of whether you're a programmer or a user, this problem is going
> to surface as soon as you start using a computer for arithmetic. Of course
> some people think that using a computer for arithmetic is as quaint as using
> duct tape to seal ducts. On The Red Green show, one guy expressed amazement
> that duct tape can be used for that, too.
> Anyway, Paul, you and I are on the same page on this issue. Ordinary
> commerce should use exact representations for decimal fractions.
Yes, I'd say same page as Bob B too, who reminded me how slim the Intel support was (and still is, I assume), where the bcd instructions would operate on only one byte. The only other point I was trying to make in my clumsy way was that some machines, such as the IBM 360/370/390's going back all the way to the mid-1960's allowed fixed point bcd up to 16 bytes and besides the binary float (which was different from the IEEE one) also had a decimal float instruction set, so you didn't have to write a loop to add, subtract, multiply or divide two decimal float numbers.
I think the current big cpu manufacturers are cavalier and lazy about this.
p Received on Thu Mar 29 2007 - 15:02:53 CEST