/* int _SubUnsArrFromUnsArr(src1,src2,dst,n)
 *
 * ARGUMENT
 *      unsigned        *src1, *src2, *dst;
 *      unsigned        n;
 *
 * DESCRIPTION
 *      Subtracts src2 from src2 giving dst. src1 and src2 are unchanged.
 *  src1, src2 and dst point to unsigned arrays.
 *
 * SIDE EFFECTS
 *
 *
 * RETURNS
 *      GM_SUCCESS if no overflow, otherwise GM_FAILURE.
 *
 * AUTHOR
 *      Brugnoli Giugno 1992
 *
 * MODIFICATIONS
 *
 */

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

extern double pow(double, double);

int _SubUnsArrFromUnsArr(src1, src2, dst, n)
unsigned SHORT        src1[], src2[], dst[];
int             n;
{
  int i;
  unsigned long psrc,maxunsint;
  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++)
      {
      if (src2[i]>src1[i])
        {
        psrc=maxunsint+0x1L+(long)src1[i]-(long)carry;
        carry=1;
        }
      else
        {
        psrc=src1[i]-carry;
        carry=0;
        }
      dst[i]=(unsigned SHORT)(psrc-(unsigned long)src2[i]);
      }
    if (carry)
      {
      return(GM_FAILURE);
      }
    else
      {
      return(GM_SUCCESS);
      }
    }
  else
    {
    return(GM_SUCCESS);
    }
}