x86 assembly program to search for a word in a given text - string

Question

I am trying to write a program using x86 assembly that can search for a word in a text. When the word is present in the text, the program will inform the user. I'm still having a problem in comparing the strings. Any advice?
.model small
.stack 200h
.data
message1 db "Enter your text here: $"
text db 150,151 dup(0)
message2 db 10,13,"Enter the word that you want to find: $"
find db 20,21 dup(0)
yesmessage db 10,13,"The word is in the text$"
nomessage db 10,13,"Sorry the word is not in the text$"
.code
Start:
;Display message and key in strings
mov ax,seg message1
mov ds,ax
mov si,offset text
mov di,offset find
mov dx,offset message1
mov ah,09h
int 21h
mov dx,si
mov ah,0Ah
int 21h
mov ax,seg message2
mov ds,ax
mov dx,offset message2
mov ah,09h
int 21h
mov dx,di
mov ah,0Ah
int 21h
;compare strings
mov bx,00
mov bl,text+1
mov bh,find+1
cmp bl,bh
jne L1
add si,2
add di,2
L2:mov bl,byte ptr[si]
cmp byte ptr[di],bl
jne L1
inc si
inc di
cmp byte ptr[di],"$"
jne L2
mov ah,09h
mov dx,offset yesmessage
int 21h
L1:mov ah,09h
mov dx,offset nomessage
int 21H
mov ax,4c00h
int 21h
end start
the expected result should be:
Example 1:
Enter your text here: He is old
Enter the word that you want to find: old
The word is in the text
Example 2:
Enter your text here: He is old
Enter the word that you want to find: young
Sorry the word is not in the text

Answer 1

I can see a couple of obvious problems in your code. See my comments below:
mov bx,00 ; this instruction is redundant
mov bl,text+1
mov bh,find+1
cmp bl,bh
jne L1 ; it's quite likely that the strings won't have the same length,
; i.e. that find will be shorter than text. this condition is
; therefore incorrect. it would make more sense to use jl, i.e.
; jumping to the negative print if text is shorter than find.
mov ah,09h
mov dx,offset yesmessage
int 21h
L1:mov ah,09h
mov dx,offset nomessage ; you'll be printing both messages in cases where
int 21H ; the substring is found, because you don't have
; any jump that skips past it.