campo-sirio/gfm/dmi.c

/* int _DoubleUnsArr(a,n)
 *
 * ARGUMENT
 *      unsigned        *a;
 *      int              n;
 *
 * DESCRIPTION
 *      Multiplies a by 2 and stores the result in a.
 *
 *
 * SIDE EFFECTS
 *
 *
 * RETURNS
 *      SUCCESS if no overflow, otherwise FAILURE.
 *
 * AUTHOR
 *      Brugnoli Giugno 1992
 *
 * MODIFICATIONS
 *
 */

#include <stdio.h>
#include <math.h>
#include "gm.h"
#include "gmsystem.h"

extern double pow(double, double);

unsigned _DoubleUnsArr(a,n)
unsigned SHORT 				a[];
int             n;
{
  int i;
  unsigned long maxunsint,pdst;
  unsigned SHORT carry;

  carry=0;
#ifdef SH_LIB
	maxunsint=1;
	for (i=1;i<=BITSPERUI;i++) maxunsint*=2;
	maxunsint--;
#else
  maxunsint=(unsigned long)pow(2.,(float)BITSPERUI)-1;
#endif
  if (n>0)
    {
    for (i=0;i<n;i++)
      {
      pdst=carry+(unsigned long)a[i]*2;
      if (pdst>maxunsint)
        {
        carry=(unsigned SHORT)(pdst>> BITSPERUI );
        a[i]=(unsigned SHORT)(pdst & maxunsint );
        }
      else
        {
        a[i]=(unsigned SHORT)pdst;
        carry=0; 
				}
      }
    if ((a[n-1])>>(BITSPERUI-1))
      {
      return(FAILURE);
      }
    else
      {
      return(GM_SUCCESS);
      }
    }
}