x86汇编

segment*16+offset   hex excursion

cs ip   code segment  ip  instruct pointer  

then ip+num

when 8086 cpu start it begin excuting from base cs=FFFFH IP=0000H   the result is FFFF0H

jmp s:o

ds  data segment   mov bx,1000H

                              mov ds,bx

                               mov al,[0]        mov ds 1000H  is illegal   must use a register for  transfer

sub   reverse add function

push pop 

when the stack is empty  sp is   below the high memory 

pop sp+2   push sp-2

10000H~1000FH   sp is 1000FH+1=10010H

segment register CS DS SS ES

(ax)    mov ax,[ax]

mov bx,idata

loop   (cx)=(cx)-1  if cx=0 goto next code

  mov cx,11

s: add ax,ax

    loop s

inc bx bx=bx+1

[bx] is offset

architecture

assume  cs:code

code segment

code ends

end

si di the function is same with bx

[bx+si]   [bx+si+idata]

when you want to store data  you should use stack  

[....]  bx si di bp

[bp] the segment is  ss 

word byte ptr

div be dived is ax or ax+dx  and is double of div      dx is high  ax is low

al  is integer   ah is remainder  

div word ptr [bx+si+8]

ax=[(dx)*10000h+ax]/(ds*16+bx+si+8)

dd doubleword

db 3 dup(0)   db 0 ,0, 0 

jmp ax 

jmp 1000:0

offset   mov ax,offset start

jmp short s

s:inc ax       short range from  -128~127

the location is next line jmp s  s location -end

jmp far ptr  flag

jmp word ptr  segment transfer

mov dword ptr ds:[0]   

cs=ds[2]  ip=ds[0]

mov ax,0123H

mov [bx],ax

mov word ptr [bx+2],0

jmp dword ptr [bx]       cs=high is 0  ip =low is 0123H

jcxz   jmp with options  short transfer  from -128~127

cx=0  jmp flag

cx!=0 do next  

B8000H~BFFFFH show in the terminal

B800:0000

ret use stack data to modify ip

retf to mofiy cs ip

ret 

retf  ip=ss*16+sp

       sp+2

        cs=ss*16+sp

       sp+2

pop ip 

pop cs

call  push   transfer    long transfer

push ip

jmp near ptr flag

call far ptr flag  long transfer 

push cs

push ip

jmp far ptr flag

call register  

push  ip

jmp register

call word ptr memory

push ip 

jmp word ptr memory

call dword prt memory

push cs 

push ip

jmp dword ptr memory

mul    multiply   bit is same 8 or 16 together    

8 store in al  other is in reg or memory   result is in ax  

16 store in ax other is in reg or memory   result  h is in dx l is in ax

jcxz ok  

zf   0 flag  pf   1 count is  even   pf=1 or is uneven pf =0

cf carry

sf result <0 sf=1 

cf carry 

of  override flag   is true is 1

adc  ax,bx  ax=ax+bx+cf

sbb ax,bx  ax=ax-bx-cf  

cmp ax,bx  flag chang   ax=bx zf =1

je

jne

jb

jnb

ja

jna

df   =0   si di inc  else des

movsb    es*16+di=ds*16+si

             if df=0  di si inc

pushf popf  flag operation

 

0000:0000~0000:03FF break  table

iret  pop ip

pop cs popf

n

ip=n*4  cs =n*4+2

shl  left move  write last byte into cf  and  add 0

int 9h key

int  13h disk

lea reg  mem  

disp proc forge instruct     proc near or far   subprocess   

ret

disp endp

DATA SEGMENT
str db 'Hello!'
len equ $-str ; len为str所指字符串长度 
DATA ENDS

CODE SEGMENT
ASSUME CS:CODE, DS:DATA
START:
MOV AX, DATA
MOV DS, AX
MOV CX, len ; CX保存循环次数
LEA SI, str ; 字符串首地址送SI
DISPLAY:
MOV DL, [SI] ; 依次取str所指字符串中单个字符送DL
CALL DISP ; 调用显示字符子程序
INC SI ; 字符串偏移地址加1
LOOP DISPLAY
MOV AH, 4CH
INT 21H

;显示字符子程序，入口参数在DL
DISP PROC
PUSH AX
MOV AH,02H
INT 21H
POP AX
RET

DISP ENDP

CODE ENDS

END START

int 02h  the data must be in dl

bp  base pointer  store stack and heap call function when function is over it make sure it can call back right

push    ebp

mov     ebp, esp   the top of stack point to ebp

common reg  si di

bp point to top of stack below

stosb transfer al to es:di if df=0 di+1

MOV ES:DI,AL INC DI   

MOV ES:DI,AL DEC DI

ebp donot change point to bottom of stack

rep       replicate 

两者的区别在于SAR右移时保留操作数的符号，即用符号位来补足，而SHR右移时总是用0来补足。

ES寄存器   附加段寄存器：定义附加段的起始地址

例如10000000算数右移一位是11000000，而逻辑右移一位是01000000。

ds:si  es:di  

前面的表示源，后面的表示目的地。

test and

 cmp  sub