What is the minimum precision allowed for floats.

[Vincent Diepeveen]

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