/* int _MulUnsArrByPwrOf10(pa,n,w)
 *
 * ARGUMENT
 *      unsigned        pa[];
 *      int             n;            power of 10 to multiply by
 *      int             w;            number of digits
 *
 * DESCRIPTION
 *      Multiplies the pa[] array by 10^n (0<n<47),
 *
 * SIDE EFFECTS
 *      The value of pa is unchanged on overflow.
 *
 * RETURNS
 *      GM_SUCCES if no overflow, otherwise GM_OVERFLOW
 *
 * AUTHOR
 *      Brugnoli Giugno 1992
 *
 * MODIFICATIONS
 *
 */

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

extern double pow(double, double);

int Multiply(sr,num,m)
unsigned SHORT  sr[],num;
int       m;
{
  int i;
  unsigned long pdst[10],maxunsint;
  unsigned SHORT carry;

#ifdef SH_LIB
	maxunsint=1;
	for (i=1;i<=BITSPERUI;i++) maxunsint*=2;
	maxunsint--;
#else
  maxunsint=(unsigned long)pow(2.,(float)BITSPERUI)-1;
#endif
  carry=0;

  for (i=0;i<m;i++)
    {
    pdst[i]=(unsigned long)sr[i]*num;
    }

  for (i=0;i<m;i++)
    {
    pdst[i]+=carry;
    if (pdst[i]>maxunsint)
      {
      carry=(unsigned SHORT)(pdst[i]>>BITSPERUI);
      sr[i]=(unsigned SHORT)(pdst[i]&maxunsint);
      }
    else
      {
      carry=0;
      sr[i]=(unsigned SHORT)pdst[i];
      }
    }
  return( (carry)? GM_OVERFLOW : GM_SUCCESS );
}


int    _MulUnsArrByPwrOf10(pa,n,w)
unsigned SHORT        pa[];
int             n,w;
{

int ppdf,k,i;

  k=GM_SUCCESS;

  if (n>47)
    {
    k=GM_OVERFLOW;
    }

  while ((n>4)&&(k==GM_SUCCESS))
    {
    k=Multiply(pa,10000,w);
    n-=4;
    }

  if (k!=GM_OVERFLOW)
    {
#ifdef SH_LIB
		ppdf=1;
		for (i=1;i<=n;i++) ppdf*=10;
#else
    ppdf=(int)pow(10.,(double)n);
#endif
    k=Multiply(pa,ppdf,w);
    }

  return(k);

}