arch/ia64/lib/strnlen_user.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Returns 0 if exception before NUL or reaching the supplied limit (N),
   4  * a value greater than N if the string is longer than the limit, else
   5  * strlen.
   6  *
   7  * Inputs:
   8  *      in0:    address of buffer
   9  *      in1:    string length limit N
  10  * Outputs:
  11  *      r8:     0 in case of fault, strlen(buffer)+1 otherwise
  12  *
  13  * Copyright (C) 1999, 2001 David Mosberger-Tang <davidm@hpl.hp.com>
  14  */
  15
  16 #include <asm/asmmacro.h>
  17 #include <asm/export.h>
  18
  19 GLOBAL_ENTRY(__strnlen_user)
  20         .prologue
  21         alloc r2=ar.pfs,2,0,0,0
  22         .save ar.lc, r16
  23         mov r16=ar.lc                   // preserve ar.lc
  24
  25         .body
  26
  27         add r3=-1,in1
  28         ;;
  29         mov ar.lc=r3
  30         mov r9=0
  31         ;;
  32         // XXX braindead strlen loop---this needs to be optimized
  33 .Loop1:
  34         EXCLR(.Lexit, ld1 r8=[in0],1)
  35         add r9=1,r9
  36         ;;
  37         cmp.eq p6,p0=r8,r0
  38 (p6)    br.cond.dpnt .Lexit
  39         br.cloop.dptk.few .Loop1
  40
  41         add r9=1,in1                    // NUL not found---return N+1
  42         ;;
  43 .Lexit:
  44         mov r8=r9
  45         mov ar.lc=r16                   // restore ar.lc
  46         br.ret.sptk.many rp
  47 END(__strnlen_user)
  48 EXPORT_SYMBOL(__strnlen_user)