2 * String handling functions for PowerPC.
4 * Copyright (C) 1996 Paul Mackerras.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
11 #include <asm/processor.h>
12 #include <asm/errno.h>
13 #include <asm/ppc_asm.h>
15 .section __ex_table,"a"
28 /* This clears out any unused part of the destination buffer,
29 just as the libc version does. -- paulus */
39 bdnzf 2,1b /* dec ctr, branch if ctr != 0 && !cr0.eq */
40 bnelr /* if we didn't hit a null char, we're done */
42 cmpwi 0,r5,0 /* any space left in destination buffer? */
43 beqlr /* we know r0 == 0 here */
44 2: stbu r0,1(r6) /* clear it out if so */
120 _GLOBAL(__clear_user)
126 /* clear a single word */
129 /* clear word sized chunks */
139 /* clear byte sized chunks */
156 .section __ex_table,"a"
162 _GLOBAL(__strncpy_from_user)
171 bdnzf 2,1b /* dec ctr, branch if ctr != 0 && !cr0.eq */
179 .section __ex_table,"a"
183 /* r3 = str, r4 = len (> 0), r5 = top (highest addr) */
184 _GLOBAL(__strnlen_user)
186 subf r6,r7,r5 /* top+1 - str */
190 0: mtctr r6 /* ctr = min(len, top - str) */
191 1: lbzu r0,1(r7) /* get next byte */
193 bdnzf 2,1b /* loop if --ctr != 0 && byte != 0 */
195 subf r3,r3,r7 /* number of bytes we have looked at */
196 beqlr /* return if we found a 0 byte */
197 cmpw 0,r3,r4 /* did we look at all len bytes? */
198 blt 99f /* if not, must have hit top */
199 addi r3,r4,1 /* return len + 1 to indicate no null found */
201 99: li r3,0 /* bad address, return 0 */
204 .section __ex_table,"a"