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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/arm/lib/strnlen_user.S
3 *
4 * Copyright (C) 1995-2000 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <linux/linkage.h>
11#include <asm/assembler.h>
12#include <asm/errno.h>
13
14 .text
15 .align 5
16
Russell King02fcb972006-06-21 14:44:52 +010017/* Prototype: unsigned long __strnlen_user(const char *str, long n)
Linus Torvalds1da177e2005-04-16 15:20:36 -070018 * Purpose : get length of a string in user memory
19 * Params : str - address of string in user memory
20 * Returns : length of string *including terminator*
21 * or zero on exception, or n + 1 if too long
22 */
Russell King02fcb972006-06-21 14:44:52 +010023ENTRY(__strnlen_user)
Linus Torvalds1da177e2005-04-16 15:20:36 -070024 mov r2, r0
251:
26USER( ldrbt r3, [r0], #1)
27 teq r3, #0
28 beq 2f
29 subs r1, r1, #1
30 bne 1b
31 add r0, r0, #1
322: sub r0, r0, r2
Russell King405040a2006-06-25 11:37:09 +010033 mov pc, lr
Catalin Marinas93ed3972008-08-28 11:22:32 +010034ENDPROC(__strnlen_user)
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
36 .section .fixup,"ax"
37 .align 0
389001: mov r0, #0
Russell King405040a2006-06-25 11:37:09 +010039 mov pc, lr
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 .previous