99 lines
2.4 KiB
C
99 lines
2.4 KiB
C
/****************************************************************
|
|
|
|
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 (dmg at acm dot org,
|
|
* with " at " changed at "@" and " dot " changed to "."). */
|
|
|
|
#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;
|
|
}
|