80x86 assembly languageprogram structure and simple I/O

Assistant : 蘇建仲 (Su Jain-Zhong)LAB : ISMP LABTel : 62530-58E-Mail : sujz@csie.ncku.edu.tw

INT 21H(DOS 插斷 )

輸出字元 AH=02H ; DL= 要輸出的字元 PUTCHAR MACRO CHAR

MOV DL,CHAR MOV AH,02H INT 21H ENDM

INT 21H(DOS 插斷 )(Cont.)

輸出字串 AH=09H ; DS:DX= 欲顯示字串起始位置 以“ $” 結束 PRINT MACRO BUFF

LEA DX,BUFF MOV AH,09H INT 21H ENDM

INT 21H(DOS 插斷 )(Cont.)

輸入字元 AH=08H READCHAR MACRO

MOV AH,08H INT 21H ENDM

AL 輸入的字元

INT 21H(DOS 插斷 )(Cont.)

輸入字串 AH=0AH ; DS:DX 緩衝區起始位置 INPUT MACRO BUFF

LEA DX,BUFF MOV AH,0AH INT 21H ENDM

最大輸入字元 實際輸入字元

輸入字串

DS:DX

An Example

Reference progam2-1

MACRO

Problem TEST ASC1,X ……………

TEST ASC2,Y L1: …………. LOOP L1 …………. L1: ………… LOOP L1 ………….

Solve

TEST MACRO STR,X ………. L1: ……….. LOOP L1 ………. ENDM

error

TEST MACRO STR,X LOCAL L1 ………. L1: ……….. LOOP L1 ………. ENDM

MARCO Lib

Reference program2-2

Subroutine

Parameter passing By register By data segment Reference example program2-3,4

Calling External Program Calling program: EXTRN var: type Called program: PUBLIC var

Type:BYTE,WORD,DWORD

Subroutine link in diff. files

PUBLIC subroutine nameEXTRN subroutine name:FAR

How to use assembler

Assembly Tool masm asm_file.asm link obj_file.obj [+ obj_file2.obj] ….. ml asm_file.asm + asm_file2.asm

Debug tool debug exe_file.exe codeview exe_file.exe