Control transfer instruction

Link to the original text —— SevenOne’Blog

skill

1. Z or E be equal to
2. G or A Greater than
3. L or B Less than
4. All jump instructions are in J start

Conditional jump instructions

1. be equal to JZ
2. It's not equal to JNZ
3. Greater than JG or JNLZ
4. Less than JL or JNGZ
5. Greater than or equal to JGZ or JNL
6. Less than or equal to JLZ or JNG

Jump unconditionally JMP

……
start:
……
jmp start

Cyclic instruction Loop

1. The initial value of the cycle can only be used cx register .

2. grammar

   mov cx,100
   start:
   	……
   loop start
   

3. Each cycle cx Value auto decrement , know cx The value is 0 End cycle at .

Program encapsulation

1. Define subroutine pseudo instructions

   • Start ：proc
   • end ：endp

2. Call Subroutine instructions ：call

3. attribute

   • Far attribute instruction ：far
   • Near attribute instruction ：near

4. Return to the main program instruction ：ret

5. grammar ： Define a name Program

   name proc near
   	 Procedural body 
   	ret
   name endp
   

6. Code demonstration

   code segment
       assume cs:code
       start:
     	
       call delay
   
       mov ah,4ch
       int 21h
       
       delay proc near
           mov ax,10
           ret
       delay endp
   code ends
       end start