On Fri, 20 Jan 2006 15:08:17 GMT, robin <robin_v@[EMAIL PROTECTED]
> wrote:
>> I don't believe that is true, I believe most floating point
>> representations that
>> have used a binary exponent have suppressed the leading one to obtain
>> one
>> more
>> bit of accuracy. But with a radix 16 exponent you can't. of course do
>> that.
>>
>> Not sure how far this goes back in time, but i bet it is to the 50's
>> anyway.
> No. The leading bit wasn't suppressed, even wh
Well, it was on a number of machines that I have worked on and since a
normalized
float always has a leading 1 for the characteristic (Mantissa) so no test
needed and
small amount of additional logic needed for the ac***ulator. Thus if the
floating
point number had a characteristic of n bits the ac***ulator would need a
minimum
of n+1 bits + possibly guard bits
> The reason was that it was more expensive (if in hardware),
> requiring a test and generation of the bit. In a serial machine,
> that wasted two machine cycles.
I don't see that, following an operation the result would need to be
normalized anyway.
> In software, all it gained was loss of time and loss of
> fast memory (always in short supply).
|
