assembly - Serie Fibonacci en ensamble x86

Question

Finalmente, después de una larga sesión de innumerables errores, espero que este sea el último.

Sin errores de compilación o tiempo de ejecución, solo un error lógico.

EDITAR: (Pseudocódigo fijo)

Mi pseudocódigo:

first  = 1;
second = 1;
third  = 0;

 for i from 1 to n{

    third=first+second
    first=second
    second=third

}
return third

Esto imprimiría el resultado final de la serie.

Mi código de ensamblaje:

He añadido comentarios siempre que sea posible

.386
.model flat,stdcall
option casemap:none

.data
timestell     db "Loop Ran : %d Times -----",0     ;format string
fmtd   db "%d",0
finalprint  db "Final Number is : %d ------",0     ;format string
times  dd 0Ah                                      ;times to loop
first dd 1h
second dd 1h
third dd 0h


.data?

retvalue1 dd ?             ;we will initialize it later

.code
include windows.inc
include user32.inc
includelib user32.lib
include kernel32.inc
includelib kernel32.lib
includelib MSVCRT
extrn printf:near
extrn exit:near

public main
main proc


         mov ecx, times      ;loop "times" times
         mov eax,0           ;just to store number of times loop ran
      top:                   ;body of loop
         cmp ecx, 0          ;test at top of loop
         je bottom           ;loop exit when while condition false
         add eax,1           ;Just to test number of times loop ran
         mov ebx,first       ;move first into ebx
         add ebx,second      ;add ebx, [ first+second ]
         mov third,ebx       ;Copy result i.e ebx [first+second] to third
         xor ebx,ebx         ;clear for further use
         mov ebx,first       ;move first into ebx
         mov second,ebx      ;copy ebx to second [NOW second=first]
         xor ebx,ebx         ;clear for later use
         mov ebx,third       ;move thirs into ebx
         mov second,ebx      ;copy ebx to third [NOW second=third]
         xor ebx,ebx         ;clear it
         dec ecx             ;decrement loop
         jmp top             ;Loop again

      bottom:
           mov retvalue1,eax       ;store eax into a variable
           push retvalue1          ;pass this variable to printf
           push offset timestell   ;pass Format string to printf    
           call printf             ;Print no.  of times loop ran
           push third              ;push value of third to printf
           push offset finalprint  ;push the format string
           call printf             ;Print the final number


      push 0        ;exit gracefully
      call exit     ;exit system

main endp

end main

El código funciona bien pero la salida no me satisface:

Salida: Loop Ran : 10 Times -----Final Number is : 11 ------

En primer lugar, no estoy seguro de que el número final esté en forma decimal o hexagonal.

• Asumiéndolo como decimal: la serie de Fibonacci no tiene 11
• Asumiendo que es un hex: la serie Fibonacci no tiene 17 (11 hex = 17 dec)

¿Qué estoy haciendo mal?

Answer 1

El problema era que mi código real no coincidía con mi pseudocódigo que dio como resultado el error lógico.

Esta parte

     mov ebx,first       ;move first into ebx
     mov second,ebx      ;copy ebx to second [NOW second=first]

Esto da el first valor de second , pero mi PseudoCódigo dice "primero = segundo", lo que significa dar valor de second a first .

     mov ebx,second      ;move second into ebx
     mov first,ebx       ;copy ebx to second [NOW first=second]

Código de trabajo final para el procesador Intel x86:

Para cualquier otra referencia, estoy publicando un código de trabajo para Intel x86

.386
.model flat,stdcall
option casemap:none

.data
timestell   db   "Loop Ran : %d Times -----",0          ;format string
finalprint  db   "%d th Fibonacci number is %d",0       ;format string
times       dd   14h                                    ;times to loop
first dd 1h
second dd 1h
third dd 0h



.code
include windows.inc
include user32.inc
includelib user32.lib
include kernel32.inc
includelib kernel32.lib
includelib MSVCRT
extrn printf:near
extrn exit:near

public main
main proc


         mov ecx, times       ;set loop counter to "times" time
         sub ecx,2            ;loop times-2 times

      top:
         cmp ecx, 0          ; test at top of loop
         je bottom           ; loop exit when while condition false
         xor ebx,ebx         ;Clear ebx
         mov ebx,first       ;move first into ebx
         add ebx,second      ;add ebx, [ first+second ]
         mov third,ebx       ;Copy result i.e ebx [first+second] to third
         xor ebx,ebx         ;clear for further use
         mov ebx,second      ;move second into ebx
         mov first,ebx       ;copy ebx to second [NOW first=second]
         xor ebx,ebx         ;clear for later use
         mov ebx,third       ;move thirs into ebx
         mov second,ebx      ;copy ebx to third [NOW second=third]
         xor ebx,ebx         ;clear it
         dec ecx             ;decrement loop
         jmp top             ;Loop again

      bottom:
        push third
              push times                ;push value of third to printf
              push offset finalprint    ;push the format string
              call printf               ;Print the final number
      push 0        ;exit gracefully
         call exit      ;exit system

    main endp

end main