LONGITUD DE UNA CADENA DE TEXTO

      Para completar la librería STRING de manejo de cadenas vamos a publicar las funciones más necesarias. La primera y básica es strlen. 
     Esta función que calcula la longitud de una cadena.
     En este caso

STRLEN.ASM

; Copyright (C) 2013  José Ángel Moneo Fernández

;    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 3 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, see <http://www.gnu.org/licenses/>.

include main.mac
_modelo exe
_code
rutina _strlen  testo
        push bx
        mov bx,[bp].texto
    MAS:
        cmp byte ptr [bx],0
        jz FIN
        inc bx
        jmp MAS
    FIN:
        sub bx,[bp].texto
        mov ax,bx
        pop bx
rutina_end
_data
_end