--- /dev/null
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <ao_int64.h>
+
+void ao_plus64(ao_int64_t *r, ao_int64_t *a, ao_int64_t *b) {
+ uint32_t t;
+
+ r->low = t = a->low + b->low;
+ r->high = a->high + b->high;
+ if (t < a->low)
+ r->high++;
+}
+
+void ao_rshift64(ao_int64_t *r, ao_int64_t *a, uint8_t d) {
+ if (d < 32) {
+ r->high = (int32_t) a->high >> d;
+ r->low = a->low >> d;
+ if (d)
+ r->low |= a->high << (32 - d);
+ } else {
+ d &= 0x1f;
+ r->high = 0;
+ r->low = (int32_t) a->high >> d;
+ }
+}
+
+void ao_lshift64(ao_int64_t *r, ao_int64_t *a, uint8_t d) {
+ if (d < 32) {
+ r->high = a->high << d;
+ r->low = a->low << d;
+ if (d)
+ r->high |= a->low >> (32 - d);
+ } else {
+ d &= 0x1f;
+ r->low = 0;
+ r->high = a->low << d;
+ }
+}
+
+void ao_umul64(ao_int64_t *r, uint32_t a, uint32_t b)
+{
+ uint32_t r1;
+ uint32_t r2, r3, r4;
+ ao_int64_t s,t,u,v;
+ r1 = (uint32_t) (uint16_t) a * (uint16_t) b;
+ r2 = (uint32_t) (uint16_t) (a >> 16) * (uint16_t) b;
+ r3 = (uint32_t) (uint16_t) a * (uint16_t) (b >> 16);
+ r4 = (uint32_t) (uint16_t) (a >> 16) * (uint16_t) (b >> 16);
+
+ s.low = r1;
+ s.high = r4;
+
+ t.high = (uint32_t) r2 >> 16;
+ t.low = r2 << 16;
+ ao_plus64(&u, &s, &t);
+
+ v.high = (int32_t) r3 >> 16;
+ v.low = r3 << 16;
+ ao_plus64(r, &u, &v);
+}
+
+void ao_neg64(ao_int64_t *r, ao_int64_t *a) {
+ r->high = ~a->high;
+ r->low = ~a->low;
+ if (!++r->low)
+ r->high++;
+}
+
+void ao_mul64(ao_int64_t *r, int32_t a, int32_t b) {
+ uint8_t negative = 0;
+
+ if (a < 0) {
+ a = -a;
+ negative = 1;
+ }
+ if (b < 0) {
+ b = -b;
+ negative = !negative;
+ }
+ ao_umul64(r, a, b);
+ if (negative)
+ ao_neg64(r, r);
+}
+
+void ao_umul64_16(ao_int64_t *r, ao_int64_t *a, uint16_t b) {
+ uint32_t low = a->low;
+ ao_umul64(r, (uint32_t) low >> 1, (uint32_t) b << 1);
+ if (low & 1) {
+ if ((uint32_t) (r->low += b) < (uint32_t) b)
+ r->high++;
+ }
+ r->high += a->high * b;
+}
+
+void ao_mul64_16(ao_int64_t *r, ao_int64_t *a, uint16_t b) {
+ if ((int32_t) a->high < 0) {
+ ao_int64_t t;
+
+ ao_neg64(&t, a);
+ ao_umul64_16(r, &t, b);
+ ao_neg64(r, r);
+ } else
+ ao_umul64_16(r, a, b);
+}