int fp_cmp_mag(fp_int *a, fp_int *b)
{
   int x;

   if (a->used > b->used) {
      return FP_GT;
   } else if (a->used < b->used) {
      return FP_LT;
   } else {
      for (x = a->used - 1; x >= 0; x--) {
          if (a->dp[x] > b->dp[x]) {
             return FP_GT;
          } else if (a->dp[x] < b->dp[x]) {
             return FP_LT;
          }
      }
   }
   return FP_EQ;
}
int fp_cmp_mag(fp_int *a, fp_int *b)
{
   int x;

   if (a->used > b->used) {
      return FP_GT;
   } else if (a->used < b->used) {
      return FP_LT;
   } else {
      for (x = a->used - 1; x >= 0; x--) {
          if (a->dp[x] > b->dp[x]) {
             return FP_GT;
          } else if (a->dp[x] < b->dp[x]) {
             return FP_LT;
          }
      }
   }
   return FP_EQ;
}