sdcc/device/lib/sm83/strlen.s

   1 ;--------------------------------------------------------------------------
   2 ;  strlen.s
   3 ;
   4 ;  Copyright (C) 2020, Tony Pavlov
   5 ;  Copyright (c) 2021, Philipp Klaus Krause
   6 ;
   7 ;  This library is free software; you can redistribute it and/or modify it
   8 ;  under the terms of the GNU General Public License as published by the
   9 ;  Free Software Foundation; either version 2, or (at your option) any
  10 ;  later version.
  11 ;
  12 ;  This library is distributed in the hope that it will be useful,
  13 ;  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 ;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15 ;  GNU General Public License for more details.
  16 ;
  17 ;  You should have received a copy of the GNU General Public License
  18 ;  along with this library; see the file COPYING. If not, write to the
  19 ;  Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  20 ;   MA 02110-1301, USA.
  21 ;
  22 ;  As a special exception, if you link this library with other files,
  23 ;  some of which are compiled with SDCC, to produce an executable,
  24 ;  this library does not by itself cause the resulting executable to
  25 ;  be covered by the GNU General Public License. This exception does
  26 ;  not however invalidate any other reasons why the executable file
  27 ;   might be covered by the GNU General Public License.
  28 ;--------------------------------------------------------------------------
  29
  30         .area   _CODE
  31
  32         .globl  _strlen
  33
  34 _strlen::
  35         ld      l, e
  36         ld      h, d
  37         ld      bc, #0
  38 loop:   ld      a, (hl+)
  39         or      a
  40         ret     Z
  41         inc     bc
  42         jr      loop
  43