kolibrios/programs/demos/aclock/trunk/strlen.inc

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; strlen function
;
; Copyright (c) 2003 Thomas Mathys
; killer@vantage.ch
;
; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, write to the Free Software
; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
;
%ifndef _STRLEN_INC
%define _STRLEN_INC
;********************************************************************
; returns the length of an asciiz string
; input : esi = pointer to string
; output : eax = string length
; destroys : nothing
;********************************************************************
strlen:
push ecx
push edi
pushfd
cld ; !
mov ecx,-1
mov edi,esi ; find terminating zero
xor al,al
repne scasb
mov eax,edi ; calculate string length
sub eax,esi
dec eax
popfd
pop edi
pop ecx
ret
%endif