1 /*- 2 * Copyright (c) 1992 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This software was developed by the Computer Systems Engineering group 6 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 7 * contributed to Berkeley. 8 * 9 * %sccs.include.redist.c% 10 */ 11 12 #if defined(LIBC_SCCS) && !defined(lint) 13 static char sccsid[] = "@(#)subdi3.c 5.4 (Berkeley) 06/02/92"; 14 #endif /* LIBC_SCCS and not lint */ 15 16 #include "quad.h" 17 18 /* 19 * Subtract two quad values. This is trivial since a one-bit carry 20 * from a single u_long difference x-y occurs if and only if (x-y) > x. 21 */ 22 quad 23 __subdi3(quad a, quad b) 24 { 25 union uu aa, bb, diff; 26 27 aa.q = a; 28 bb.q = b; 29 diff.ul[L] = aa.ul[L] - bb.ul[L]; 30 diff.ul[H] = aa.ul[H] - bb.ul[H] - (diff.ul[L] > aa.ul[L]); 31 return (diff.q); 32 } 33