1 /* 2 * Copyright (c) 1988 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #if defined(LIBC_SCCS) && !defined(lint) 19 static char sccsid[] = "@(#)swab.c 5.4 (Berkeley) 06/27/88"; 20 #endif /* LIBC_SCCS and not lint */ 21 22 /* 23 * Swab bytes 24 * Jeffrey Mogul, Stanford 25 */ 26 27 swab(from, to, n) 28 register char *from, *to; 29 register int n; 30 { 31 register unsigned long temp; 32 33 n >>= 1; n++; 34 #define STEP temp = *from++,*to++ = *from++,*to++ = temp 35 /* round to multiple of 8 */ 36 while ((--n) & 07) 37 STEP; 38 n >>= 3; 39 while (--n >= 0) { 40 STEP; STEP; STEP; STEP; 41 STEP; STEP; STEP; STEP; 42 } 43 } 44