geo
Posts:
38
Registered:
6/19/08
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Re: Implementing the KISS4691 RNG
Posted:
Sep 7, 2010 8:54 AM
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On Sep 5, 5:19 pm, Ian Collins <ian-n...@hotmail.com> wrote:
> On 09/ 6/10 09:04 AM, geo wrote:
>
> <snip>
>
>
>
> > Thus I suggest using this listing for the MWC function
> > in KISS4691:
> > ------------------------------------------------
>
> > unsigned long MWC(void)
> > {unsigned long t,x; static c=0,j=4691;
>
> static what?
>
> > j=(j<4690)? j+1:0;
> > x=Q[j]; t=(x<<13)+c;
> > if(t<c) {c=(x>>19)+1; t=t+x;}
> > else {t=t+x; c=(x>>19)+(t<x);}
> > return (Q[j]=t);
> > }
>
> This code must be making assumptions about sizes, it gives different
> results in 32 and 64 bit mode.
>
>
>
>
> Try compiling with warnings enabled!
>
> --
> Ian Collins
Evidently I had in mind: here is a list of unsigned longs,
unsigned long t,x; static c=0,j=4691;
among which I want c and j to be saved after each call.
Wrong thinking, but why did the compiler let me get away with it?
Sorry for that; I'll first try full warnings from now on.
George Marsaglia
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