What is the minimum precision allowed for floats.
Vincent Diepeveen
diep at xs4all.nl
Mon Sep 29 14:35:38 CEST 2008
If i may ask, how can you reply before i see my own posting on the list?
Yeah it's maximum of factor 2.
We don't do it in floating point of course which is 2 lousy
instructions a cycle.
Let's do it in 64 bits integers @ 3 to 4 instructions a cycle :)
Vincent
On Sep 29, 2008, at 2:31 PM, Décio Luiz Gazzoni Filho wrote:
>
> On Sep 29, 2008, at 8:59 AM, Vincent Diepeveen wrote:
>
>> Nah not factor 100.
>>
>> After most mathematical calculation you just AND with 0xffffffff
>> to get 48 bits precision.
>>
>
> You'd be right if you were doing integer arithmetic. It's floating
> point, though, so you have more work to do than just arithmetic and
> masking: the overhead of doing sign-magnitude calculations on two's
> complement hardware, lining up the mantissas, adjusting the
> exponent, rounding, etc. If you want to conform to IEEE 754, it's
> even harder.
>
> Perhaps 100x was exaggerated, but I don't think 10x is far off.
>
> Décio
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