[Scilab-users] Bitget for int64/uint64

[Samuel Gougeon]

Hello Jan,

You will find => there 
<https://codereview.scilab.org/cat/21421%2C2%2Cscilab/modules/elementary_functions/macros/bitget.sci> 
a fixed version of bitget() for big u-int64 integers.
You can patch your Scilab 6.1.0 installation in the following way:

  * download and unzip the file. rename it bitget.sci
  * put bitget.sci in the SCI/elementary_functions/macros directory
  * Run the following Scilab code in the console:
    cd SCI/elementary_functions/macros
    predef clear
    genlib elementary_functionslib
    clear bitget

And then test and use bitget in the current session and all forthcoming 
ones.

Regards
Samuel

Le 27/02/2020 à 16:17, JLan a écrit :
> I wonder if i have misunderstood the documentation for bitget, or if this is
> a bug? It seems to me that numbers > 2^53 are still not handled correctly.
> --> a=uint64(2^61)
>   a  =   2305843009213693952
> --> b=uint64(2^61)+1
>   b  =   2305843009213693953
> --> bitget(a,1:64)
>   ans  =
>           column 1 to 32
>    0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
> 0  0  0  0  0  0  0
>           column 33 to 64
>    0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
> 0  0  0  0  1  0  0
>
> --> bitget(b,1:64)
>   ans  =
>           column 1 to 32
>    0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
> 0  0  0  0  0  0  0
>           column 33 to 64
>    0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
> 0  0  0  0  1  0  0

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