| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 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 | |
| 17 | /* Prototype: unsigned long __arch_strnlen_user(const char *str, long n) |
| 18 | * 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 | */ |
| 23 | ENTRY(__arch_strnlen_user) |
| 24 | save_lr |
| 25 | mov r2, r0 |
| 26 | 1: |
| 27 | USER( ldrbt r3, [r0], #1) |
| 28 | teq r3, #0 |
| 29 | beq 2f |
| 30 | subs r1, r1, #1 |
| 31 | bne 1b |
| 32 | add r0, r0, #1 |
| 33 | 2: sub r0, r0, r2 |
| 34 | restore_pc |
| 35 | |
| 36 | .section .fixup,"ax" |
| 37 | .align 0 |
| 38 | 9001: mov r0, #0 |
| 39 | restore_pc |
| 40 | .previous |