Infinite loop when doing DIV instruction

[Iván Ávalos]

I'm not sure whether this is an issue with my code or an issue with emu2. Either way, I'll report it.

Here's the procedure where this gets triggered:

capturar_dec proc
   mov     dx, 0
   mov     cx, 10000
   
bucle:
   cmp     cx, 1
   je      terminar
   
;; Capturar caracter
   mov     ah, 01h
   int     21h

;; Validar caracter
   cmp     al, '0'
   jl      terminar_error
   cmp     al, '9'
   jg      terminar_error

;; Recalcular base en CX
   push    ax
   mov     ax, cx
   mov     bl, 10
   div     bl
   mov     ah, 0
   mov     cx, ax
   pop     ax

;; Convertir caracter
   mov     ah, 0
   and     al, 0fh              ; aplicar masking a AL para convertir a número

;; Multiplicar por base
   push    dx
   mov     bx, cx
   mul     bx                   ; multiplicar AX * CX, resultado en DX:AX
   pop     dx
   
   add     dx, ax               ; acumulamos parte baja (AX) en DX como resultado

   jmp     bucle

terminar:
   ret

terminar_error:
;; Imprimir mensaje de error
   mov     ah, 09h
   lea     dx, msgerr
   int     21h

;; Terminar con código de error
   mov     ah, 4ch
   mov     al, 1
   int     21h
capturar_dec endp

[Iván Ávalos]

It also happens with DOSBOX, so it's not emu2's fault.

[Iván Ávalos]

Seems like this is the issue, for those curious about it: https://stackguides.com/questions/69573665/division-word-with-byte

[dmsc]

Yes, you are dividing "AX" by "BL", and the result is overflowing, so the exception handler is called. As you did not install an exception handler, you get stuck in an infinite loop.

Have Fun!