arch/unicore32/lib/strnlen_user.S

   1 /*
   2  * linux/arch/unicore32/lib/strnlen_user.S
   3  *
   4  * Code specific to PKUnity SoC and UniCore ISA
   5  *
   6  * Copyright (C) 2001-2010 GUAN Xue-tao
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12 #include <linux/linkage.h>
  13 #include <asm/assembler.h>
  14 #include <asm/errno.h>
  15
  16         .text
  17         .align  5
  18
  19 /* Prototype: unsigned long __strnlen_user(const char *str, long n)
  20  * Purpose  : get length of a string in user memory
  21  * Params   : str - address of string in user memory
  22  * Returns  : length of string *including terminator*
  23  *            or zero on exception, or n + 1 if too long
  24  */
  25 ENTRY(__strnlen_user)
  26         mov     r2, r0
  27 1:
  28         ldrusr  r3, r0, 1
  29         cxor.a  r3, #0
  30         beq     2f
  31         sub.a   r1, r1, #1
  32         bne     1b
  33         add     r0, r0, #1
  34 2:      sub     r0, r0, r2
  35         mov     pc, lr
  36 ENDPROC(__strnlen_user)
  37
  38         .pushsection .fixup,"ax"
  39         .align  0
  40 9001:   mov     r0, #0
  41         mov     pc, lr
  42         .popsection