#include <config.h>
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdarg.h>
#include "bcmath.h"
#include "private.h"
bc_num
_bc_do_add (n1, n2, scale_min)
bc_num n1, n2;
int scale_min;
{
bc_num sum;
int sum_scale, sum_digits;
char *n1ptr, *n2ptr, *sumptr;
int carry, n1bytes, n2bytes;
int count;
sum_scale = MAX (n1->n_scale, n2->n_scale);
sum_digits = MAX (n1->n_len, n2->n_len) + 1;
sum = bc_new_num (sum_digits, MAX(sum_scale, scale_min));
if (scale_min > sum_scale)
{
sumptr = (char *) (sum->n_value + sum_scale + sum_digits);
for (count = scale_min - sum_scale; count > 0; count--)
*sumptr++ = 0;
}
n1bytes = n1->n_scale;
n2bytes = n2->n_scale;
n1ptr = (char *) (n1->n_value + n1->n_len + n1bytes - 1);
n2ptr = (char *) (n2->n_value + n2->n_len + n2bytes - 1);
sumptr = (char *) (sum->n_value + sum_scale + sum_digits - 1);
if (n1bytes != n2bytes)
{
if (n1bytes > n2bytes)
while (n1bytes>n2bytes)
{ *sumptr-- = *n1ptr--; n1bytes--;}
else
while (n2bytes>n1bytes)
{ *sumptr-- = *n2ptr--; n2bytes--;}
}
n1bytes += n1->n_len;
n2bytes += n2->n_len;
carry = 0;
while ((n1bytes > 0) && (n2bytes > 0))
{
*sumptr = *n1ptr-- + *n2ptr-- + carry;
if (*sumptr > (BASE-1))
{
carry = 1;
*sumptr -= BASE;
}
else
carry = 0;
sumptr--;
n1bytes--;
n2bytes--;
}
if (n1bytes == 0)
{ n1bytes = n2bytes; n1ptr = n2ptr; }
while (n1bytes-- > 0)
{
*sumptr = *n1ptr-- + carry;
if (*sumptr > (BASE-1))
{
carry = 1;
*sumptr -= BASE;
}
else
carry = 0;
sumptr--;
}
if (carry == 1)
*sumptr += 1;
_bc_rm_leading_zeros (sum);
return sum;
}
bc_num
_bc_do_sub (n1, n2, scale_min)
bc_num n1, n2;
int scale_min;
{
bc_num diff;
int diff_scale, diff_len;
int min_scale, min_len;
char *n1ptr, *n2ptr, *diffptr;
int borrow, count, val;
diff_len = MAX (n1->n_len, n2->n_len);
diff_scale = MAX (n1->n_scale, n2->n_scale);
min_len = MIN (n1->n_len, n2->n_len);
min_scale = MIN (n1->n_scale, n2->n_scale);
diff = bc_new_num (diff_len, MAX(diff_scale, scale_min));
if (scale_min > diff_scale)
{
diffptr = (char *) (diff->n_value + diff_len + diff_scale);
for (count = scale_min - diff_scale; count > 0; count--)
*diffptr++ = 0;
}
n1ptr = (char *) (n1->n_value + n1->n_len + n1->n_scale -1);
n2ptr = (char *) (n2->n_value + n2->n_len + n2->n_scale -1);
diffptr = (char *) (diff->n_value + diff_len + diff_scale -1);
borrow = 0;
if (n1->n_scale != min_scale)
{
for (count = n1->n_scale - min_scale; count > 0; count--)
*diffptr-- = *n1ptr--;
}
else
{
for (count = n2->n_scale - min_scale; count > 0; count--)
{
val = - *n2ptr-- - borrow;
if (val < 0)
{
val += BASE;
borrow = 1;
}
else
borrow = 0;
*diffptr-- = val;
}
}
for (count = 0; count < min_len + min_scale; count++)
{
val = *n1ptr-- - *n2ptr-- - borrow;
if (val < 0)
{
val += BASE;
borrow = 1;
}
else
borrow = 0;
*diffptr-- = val;
}
if (diff_len != min_len)
{
for (count = diff_len - min_len; count > 0; count--)
{
val = *n1ptr-- - borrow;
if (val < 0)
{
val += BASE;
borrow = 1;
}
else
borrow = 0;
*diffptr-- = val;
}
}
_bc_rm_leading_zeros (diff);
return diff;
}