code segment
assume cs:code,ds:code
org 100h
start: jmp install
msg: db 'This program is graphics mode!',0ah,0ah,0
oldint10 dd ?
newint10:
push ax
cmp ah,00
jnz NotMode
mov al,03
NotMode:
pushf
call cs

ldint10
pop ax
retf 2
install: push cs
pop ds
mov ax,3510h
int 21h
mov word ptr oldint10,bx
mov word ptr oldint10+2,es
lea dx,newint10
mov ax,2510h
install: push cs
pop ds
mov ax,3510h
int 21h
mov word ptr oldint10,bx
mov word ptr oldint10+2,es
lea dx,newint10
mov ax,2510h
int 21h
mov dx,offset install+120h
mov cl,04h
shr dx,cl
mov ah,31h
int 21h
code ends
end start