Source to libkern/adddi3.c
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
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* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
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#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid = "@(#)adddi3.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
* Add two quads. This is trivial since a one-bit carry from a single
* u_long addition x+y occurs if and only if the sum x+y is less than
* either x or y (the choice to compare with x or y is arbitrary).
quad_t a, b;
union uu aa, bb, sum;
aa.q = a;
bb.q = b;
sum.ul[L] = aa.ul[L] + bb.ul[L];
sum.ul[H] = aa.ul[H] + bb.ul[H] + (sum.ul[L] < bb.ul[L]);