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/* See LICENSE file for copyright and license details. */
#include "internals.h"
static inline void
zadd_impl_4(z_t a, z_t b, z_t c, size_t n)
{
zahl_char_t carry = 0, tcarry;
size_t i;
for (i = 0; i < n; i++) {
tcarry = libzahl_add_overflow(a->chars + i, b->chars[i], c->chars[i]);
carry = tcarry | (zahl_char_t)libzahl_add_overflow(a->chars + i, a->chars[i], carry);
}
while (carry) {
carry = libzahl_add_overflow(a->chars + i, a->chars[i], 1);
i++;
}
if (a->used < i)
a->used = i;
}
static inline void
zadd_impl_3(z_t a, z_t b, size_t n)
{
zadd_impl_4(a, a, b, n);
}
static inline void
libzahl_zadd_unsigned(z_t a, z_t b, z_t c)
{
size_t size, n;
if (unlikely(zzero(b))) {
zabs(a, c);
return;
} else if (unlikely(zzero(c))) {
zabs(a, b);
return;
}
size = MAX(b->used, c->used);
n = b->used + c->used - size;
ENSURE_SIZE(a, size + 1);
a->chars[size] = 0;
if (a == b) {
if (a->used < c->used) {
n = c->used;
zmemset(a->chars + a->used, 0, n - a->used);
}
zadd_impl_3(a, c, n);
} else if (unlikely(a == c)) {
if (a->used < b->used) {
n = b->used;
zmemset(a->chars + a->used, 0, n - a->used);
}
zadd_impl_3(a, b, n);
} else if (likely(b->used > c->used)) {
zmemcpy(a->chars + n, b->chars + n, size - n);
a->used = size;
zadd_impl_4(a, b, c, n);
} else {
zmemcpy(a->chars + n, c->chars + n, size - n);
a->used = size;
zadd_impl_4(a, b, c, n);
}
SET_SIGNUM(a, 1);
}
void
zadd_unsigned(z_t a, z_t b, z_t c)
{
libzahl_zadd_unsigned(a, b, c);
}
void
zadd_unsigned_assign(z_t a, z_t b)
{
size_t size, n;
if (unlikely(zzero(a))) {
zabs(a, b);
return;
} else if (unlikely(zzero(b))) {
return;
}
size = MAX(a->used, b->used);
n = a->used + b->used - size;
ENSURE_SIZE(a, size + 1);
a->chars[size] = 0;
if (a->used < b->used) {
n = b->used;
zmemset(a->chars + a->used, 0, n - a->used);
}
zadd_impl_3(a, b, n);
SET_SIGNUM(a, 1);
}
void
zadd(z_t a, z_t b, z_t c)
{
if (unlikely(zzero(b))) {
SET(a, c);
} else if (unlikely(zzero(c))) {
SET(a, b);
} else if (unlikely(znegative(b))) {
if (znegative(c)) {
libzahl_zadd_unsigned(a, b, c);
SET_SIGNUM(a, -zsignum(a));
} else {
zsub_unsigned(a, c, b);
}
} else if (unlikely(znegative(c))) {
zsub_unsigned(a, b, c);
} else {
libzahl_zadd_unsigned(a, b, c);
}
}
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