153444Sbostic /*- 253444Sbostic * Copyright (c) 1992 The Regents of the University of California. 353444Sbostic * All rights reserved. 453444Sbostic * 5*53794Sbostic * This software was developed by the Computer Systems Engineering group 6*53794Sbostic * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 7*53794Sbostic * contributed to Berkeley. 8*53794Sbostic * 953444Sbostic * %sccs.include.redist.c% 1053444Sbostic */ 1153444Sbostic 1253444Sbostic #if defined(LIBC_SCCS) && !defined(lint) 13*53794Sbostic static char sccsid[] = "@(#)subdi3.c 5.4 (Berkeley) 06/02/92"; 1453444Sbostic #endif /* LIBC_SCCS and not lint */ 1553444Sbostic 16*53794Sbostic #include "quad.h" 1753459Sbostic 18*53794Sbostic /* 19*53794Sbostic * Subtract two quad values. This is trivial since a one-bit carry 20*53794Sbostic * from a single u_long difference x-y occurs if and only if (x-y) > x. 21*53794Sbostic */ 22*53794Sbostic quad 23*53794Sbostic __subdi3(quad a, quad b) 2453444Sbostic { 25*53794Sbostic union uu aa, bb, diff; 2653444Sbostic 27*53794Sbostic aa.q = a; 28*53794Sbostic bb.q = b; 29*53794Sbostic diff.ul[L] = aa.ul[L] - bb.ul[L]; 30*53794Sbostic diff.ul[H] = aa.ul[H] - bb.ul[H] - (diff.ul[L] > aa.ul[L]); 31*53794Sbostic return (diff.q); 3253444Sbostic } 33