[org 0x0100]

02

03 jmp start

04

05 message1: dw 'abcdefg',0

06

07 message2: dw 'def',0

08

09 strlength:

10

11 push bp

12 push bp,sp

13 push ax

14 push di

15 push es

16 push ds

17 xor al,al

18

19

20 les di,[bp+4]

21 mov cx, 0xffff

22 xor al,al

23 repne SCAS

24 mov ax, 0xffff

25 sub ax, cx

26 dec ax

27 mov cx, ax

28

29 pop ds

30 pop es

31 pop di

32 pop ax

33 pop bp

34

35

36

37 start:

38

39 mov ax, message1

40 push ax

41 mov ax, message2

42 push ax

43 call strlength

44

45 CompareString:

46

47 push cx

48

49 lds si, [bp+2]

50 les di, [bp+4]

51 repne CMPS

52 dec di

53 dec si

54 cmp si,0

55 je exit

56 mov ax,1

57

58 pop cx

59

60 SubstringCompare:

61

62 repe CMPS

63 cmp cx,0

64 jne exit

65 mov ax,1

66

67 exit:

68 mov ax,0

69 mov ax, 0x4c00

70 int 0x21