Re: [ts-7000] floating point corruption?

["Daniel Serpell" <>]

Hi,

On Wed, Feb 27, 2008 at 10:19 AM, Heinrich du Toit
<> wrote:
>
>  I've compiled a program that does some floating point stuff.
>  It also communicates with my linux host PC via network.
>
[...]
>
>  I've established that network communication is not the problem.
>
>  It seem that floating point is corrupt.
>
>  When I send from the ARM to the host PC the number 1.
>  I get back 5.29981e-315  :-/

This seems an endianness problem, because if you swap the
words in a double with the number "1", you get exactly your number:

------------------------------------------------
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
 union {
   double d;
   int i[2];
 } a,b;

 if(argc>1)
  a.d = atof(argv[1]);
 else
  a.d = 1;

 b.i[0] = a.i[1];
 b.i[1] = a.i[0];
 printf("Original: [%08x%08x] %g\n",a.i[0],a.i[1],a.d);
 printf("Swapped:  [%08x%08x] %g\n",b.i[0],b.i[1],b.d);
 return 0;
}
------------------------------------------------

Try running the program above, it will show the number 5.29981e-315

I'd look on the network protocol, as you probably are not swapping
bytes correctly from network/host.

    Daniel.


 
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