/****************************************************************

The author of this software is David M. Gay.

Copyright (C) 1998 by Lucent Technologies

All Rights Reserved

Permission to use, copy, modify, and distribute this software and

its documentation for any purpose and without fee is hereby

granted, provided that the above copyright notice appear in all

copies and that both that the copyright notice and this

permission notice and warranty disclaimer appear in supporting

documentation, and that the name of Lucent or any of its entities

not be used in advertising or publicity pertaining to

distribution of the software without specific, written prior

permission.

LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,

INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.

IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY

SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER

IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,

ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF

THIS SOFTWARE.

****************************************************************/

/* Please send bug reports to

	David M. Gay

	Bell Laboratories, Room 2C-463

	600 Mountain Avenue

	Murray Hill, NJ 07974-0636

	U.S.A.

	dmg@bell-labs.com

 */

#include "gdtoaimp.h"

 Bigint *

#ifdef KR_headers

sum(a, b) Bigint *a; Bigint *b;

#else

sum(Bigint *a, Bigint *b)

#endif

{

	Bigint *c;

	ULong carry, *xc, *xa, *xb, *xe, y;

#ifdef Pack_32

	ULong z;

#endif

	if (a->wds < b->wds) {

		c = b; b = a; a = c;

		}

	c = Balloc(a->k);

	c->wds = a->wds;

	carry = 0;

	xa = a->x;

	xb = b->x;

	xc = c->x;

	xe = xc + b->wds;

#ifdef Pack_32

	do {

		y = (*xa & 0xffff) + (*xb & 0xffff) + carry;

		carry = (y & 0x10000) >> 16;

		z = (*xa++ >> 16) + (*xb++ >> 16) + carry;

		carry = (z & 0x10000) >> 16;

		Storeinc(xc, z, y);

		}

		while(xc < xe);

	xe += a->wds - b->wds;

	while(xc < xe) {

		y = (*xa & 0xffff) + carry;

		carry = (y & 0x10000) >> 16;

		z = (*xa++ >> 16) + carry;

		carry = (z & 0x10000) >> 16;

		Storeinc(xc, z, y);

		}

#else

	do {

		y = *xa++ + *xb++ + carry;

		carry = (y & 0x10000) >> 16;

		*xc++ = y & 0xffff;

		}

		while(xc < xe);

	xe += a->wds - b->wds;

	while(xc < xe) {

		y = *xa++ + carry;

		carry = (y & 0x10000) >> 16;

		*xc++ = y & 0xffff;

		}

#endif

	if (carry) {

		if (c->wds == c->maxwds) {

			b = Balloc(c->k + 1);

			Bcopy(b, c);

			Bfree(c);

			c = b;

			}

		c->x[c->wds++] = 1;

		}

	return c;

	}