arch/ia64/lib/strnlen_user.S

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