LXR linux/arch/mips/lib/strlen

   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * Copyright (C) 1996, 1998, 1999, 2004 by Ralf Baechle
   7 * Copyright (C) 1999 Silicon Graphics, Inc.
   8 * Copyright (C) 2011 MIPS Technologies, Inc.
   9 */
  10#include <asm/asm.h>
  11#include <asm/asm-offsets.h>
  12#include <asm/regdef.h>
  13
  14#define EX(insn,reg,addr,handler)                       \
  159:      insn    reg, addr;                              \
  16        .section __ex_table,"a";                        \
  17        PTR     9b, handler;                            \
  18        .previous
  19
  20/*
  21 * Return the size of a string (including the ending 0)
  22 *
  23 * Return 0 for error
  24 */
  25LEAF(__strlen_user_asm)
  26        LONG_L          v0, TI_ADDR_LIMIT($28)  # pointer ok?
  27        and             v0, a0
  28        bnez            v0, .Lfault
  29
  30FEXPORT(__strlen_user_nocheck_asm)
  31        move            v0, a0
  321:      EX(lbu, v1, (v0), .Lfault)
  33        PTR_ADDIU       v0, 1
  34        bnez            v1, 1b
  35        PTR_SUBU        v0, a0
  36        jr              ra
  37        END(__strlen_user_asm)
  38
  39.Lfault:        move            v0, zero
  40        jr              ra
  41