如何循環使用匯編語言

Question

我將如何計算斐波納契數列中的前12個值並將其放置在EAX reg中。 並顯示調用DumpRegs？ 使用間接尋址，我知道我在這里需要一個for循環，但是我不確定該怎么做。 任何幫助或提示，不勝感激。

      INCLUDE Irvine32.inc

; (insert symbol definitions here)

.data

; (insert variables here)
   Fibonacci BYTE 1, 1, 10 DUP (?)

.code
main PROC

; (insert executable instructions here)


    ; (This below will show hexa contents of string.)
      mov   esi, OFFSET Fibonacci       ; offset the variables
      mov   ebx,1                   ; byte format
      mov   ecx, SIZEOF Fibonacci       ; counter
      call  dumpMem 


    exit        ; exit to operating system
main ENDP

; (insert additional procedures here)

END main

Answer 1

您可以像這樣進行循環：

mov ecx,12
your_label:
; your code
loop your_label

除非ecx等於零，否則循環指令將ecx遞減並跳轉到指定的標簽。 您也可以像這樣構造相同的循環：

mov ecx,12
your_label:
; your code
dec ecx
jnz your_label

Answer 2

您確定需要一個for循環才能實現自己的目標，因此，也許在匯編中使用for循環的C實現可以幫助您：

Code Generation for For Loop

for (i=0; i < 100; i++)
{
  . . .
}

      * Data Register D2 is used to implement i.
      * Set D2 to zero (i=0)
      CLR.L D2

  L1  
      . . .
      * Increment i for (i++)
      ADDQ.L #1, D2
      * Check for the for loop exit condition ( i < 100)
      CMPI.L #100, D2
      * Branch to the beginning of for loop if less than flag is set
      BLT.S L1

消息來源： eventhelix.com

Answer 3

.model small
.stack 100h
.data
   msg db 'Enter height of the square form 1-9: $'
   hash db '#$'
   height db 1
   length db 0
   ctr dw 0
   msgagain db 13,10,'Do you want to repeat the program? $'
   msgend db 13,10,'Program Terminated! Press any key to exit..$'
.code
   mov ax, @data
   mov ds, ax
REPEAT:   
   mov ax, 03
   int 10h

   mov ah, 09
   lea dx, msg
   int 21h

   mov ah, 01
   int 21h

   cmp al, '1'
   jl REPEAT
   cmp al, '9'
   jg REPEAT

   sub al, 48
   mov length, al
   mov bl, 1
   mul bl

   mov height, 1  
   mov di, 1 
   mov ctr, ax

   mov cx, ax
   nextline:
      dec length

      mov ah, 02
      mov bh, 00
      mov dl, length
      mov dh, height
      int 10h

      mov cx, di
      hashtags:
         mov ah, 09
         lea dx, hash
         int 21h
      loop hashtags      

      inc di
      inc height
      mov cx, ctr
      dec ctr
   loop nextline

   mov ah, 09
   lea dx, msgagain
   int 21h

   mov ah, 01
   int 21h

   cmp al, 'Y'
   je REPEAT
   cmp al, 'y'
   je REPEAT   

   mov ah, 09
   lea dx, msgend
   int 21h

   mov ah, 01
   int 21h

   mov ah, 4ch
   int 21h

END