Maths error

[Hendrik van Rooyen]

"Nick Maclaren" <nmm1 at cus.cam.ac.uk> wrote:

> The "cheap" means "cheap in hardware" - it needs very little logic,
> which is why it was used on the old, discrete-logic, machines.
> 
> I have been told by hardware people that implementing IEEE 754 rounding
> and denormalised numbers needs a horrific amount of logic - which is
> why only IBM do it all in hardware.  And the decimal formats are
> significantly more complicated.
> 
> What I don't know is how much precision this approximation loses when
> used in real applications, and I have never found anyone else who has
> much of a clue, either.
> 
I would suspect that this is one of those questions which are simple
to ask, but horribly difficult to answer - I mean - if the hardware has 
thrown it away, how do you study it - you need somehow two
different parallel engines doing the same stuff, and comparing the 
results, or you have to write a big simulation, and then you bring 
your simulation errors into the picture - There be Dragons...

- Hendrik