| 1 | /* $NetBSD: sum.c,v 1.1.1.1.14.1 2008/04/08 21:10:55 jdc Exp $ */
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| 2 |
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| 3 | /****************************************************************
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| 4 |
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| 5 | The author of this software is David M. Gay.
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| 6 |
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| 7 | Copyright (C) 1998 by Lucent Technologies
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| 8 | All Rights Reserved
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| 9 |
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| 10 | Permission to use, copy, modify, and distribute this software and
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| 11 | its documentation for any purpose and without fee is hereby
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| 12 | granted, provided that the above copyright notice appear in all
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| 13 | copies and that both that the copyright notice and this
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| 14 | permission notice and warranty disclaimer appear in supporting
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| 15 | documentation, and that the name of Lucent or any of its entities
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| 16 | not be used in advertising or publicity pertaining to
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| 17 | distribution of the software without specific, written prior
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| 18 | permission.
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| 19 |
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| 20 | LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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| 21 | INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
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| 22 | IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
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| 23 | SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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| 24 | WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
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| 25 | IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
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| 26 | ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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| 27 | THIS SOFTWARE.
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| 28 |
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| 29 | ****************************************************************/
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| 30 |
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| 31 | /* Please send bug reports to David M. Gay (dmg at acm dot org,
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| 32 | * with " at " changed at "@" and " dot " changed to "."). */
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| 33 | #include <LibConfig.h>
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| 34 |
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| 35 | #include "gdtoaimp.h"
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| 36 |
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| 37 | Bigint *
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| 38 | #ifdef KR_headers
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| 39 | sum(a, b) Bigint *a; Bigint *b;
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| 40 | #else
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| 41 | sum(Bigint *a, Bigint *b)
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| 42 | #endif
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| 43 | {
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| 44 | Bigint *c;
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| 45 | ULong carry, *xc, *xa, *xb, *xe, y;
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| 46 | #ifdef Pack_32
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| 47 | ULong z;
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| 48 | #endif
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| 49 |
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| 50 | if (a->wds < b->wds) {
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| 51 | c = b; b = a; a = c;
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| 52 | }
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| 53 | c = Balloc(a->k);
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| 54 | if (c == NULL)
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| 55 | return NULL;
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| 56 | c->wds = a->wds;
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| 57 | carry = 0;
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| 58 | xa = a->x;
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| 59 | xb = b->x;
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| 60 | xc = c->x;
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| 61 | xe = xc + b->wds;
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| 62 | #ifdef Pack_32
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| 63 | do {
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| 64 | y = (*xa & 0xffff) + (*xb & 0xffff) + carry;
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| 65 | carry = (y & 0x10000) >> 16;
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| 66 | z = (*xa++ >> 16) + (*xb++ >> 16) + carry;
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| 67 | carry = (z & 0x10000) >> 16;
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| 68 | Storeinc(xc, z, y);
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| 69 | }
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| 70 | while(xc < xe);
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| 71 | xe += a->wds - b->wds;
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| 72 | while(xc < xe) {
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| 73 | y = (*xa & 0xffff) + carry;
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| 74 | carry = (y & 0x10000) >> 16;
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| 75 | z = (*xa++ >> 16) + carry;
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| 76 | carry = (z & 0x10000) >> 16;
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| 77 | Storeinc(xc, z, y);
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| 78 | }
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| 79 | #else
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| 80 | do {
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| 81 | y = *xa++ + *xb++ + carry;
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| 82 | carry = (y & 0x10000) >> 16;
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| 83 | *xc++ = y & 0xffff;
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| 84 | }
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| 85 | while(xc < xe);
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| 86 | xe += a->wds - b->wds;
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| 87 | while(xc < xe) {
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| 88 | y = *xa++ + carry;
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| 89 | carry = (y & 0x10000) >> 16;
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| 90 | *xc++ = y & 0xffff;
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| 91 | }
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| 92 | #endif
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| 93 | if (carry) {
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| 94 | if (c->wds == c->maxwds) {
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| 95 | b = Balloc(c->k + 1);
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| 96 | if (b == NULL)
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| 97 | return NULL;
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| 98 | Bcopy(b, c);
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| 99 | Bfree(c);
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| 100 | c = b;
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| 101 | }
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| 102 | c->x[c->wds++] = 1;
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| 103 | }
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| 104 | return c;
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| 105 | }
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