LXR linux/arch/ia64/lib/strnlen

   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
  17GLOBAL_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
  45END(__strnlen_user)
  46