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