;This program recives a string input from the user prints it back in segments
.model small
.stack 100h
.data
                                        
p = 50                  ;maximum string support: 49 chars

st_msg db 'Enter your string: ',0dh,0ah,'> $'
in_str db p,0, 49 dup (0dh),'$'
wStr db 23,0, 22 dup (0),'$'
fin_msg db 'Press any key.$'
count db ?
pause dw ?
pause1 dw ?

.code

init: mov ax,@data
      mov ds,ax 
      mov ax,3
      int 10h
      
      lea dx,st_msg      ;prints out st_msg
      mov ah,9           ;
      int 21h            ;
      
      lea dx,in_str      ;read in_str
      mov ah,0ah         ;
      int 21h            ;
      
      call chrfix
      call newl 
      call newl
      
      mov si,0
      mov cx,p
edit: cmp in_str+si+15,0dh  ;stop condition
      je done       
      call special       ;creates one line
      
      lea dx,wStr        ;print out the current wStr
      mov ah,9           ;
      int 21h            ;
      mov dl,0dh         ;returns to the beginning of the line
      mov ah,2           ;
      int 21h            ;
      
      call wait1
      
      inc si      
      loop edit
      
      mov bp,0
done: mov in_str+si+15,' '
      call special
      
      lea dx,wStr        ;print out the current wStr
      mov ah,9           ;
      int 21h            ;
      mov dl,0dh         ;returns to the beginning of the line
      mov ah,2           ;
      int 21h            ;
      
      call wait1
      
      inc si
      inc bp
      cmp bp,16
      jne done
      
      call newl
      call newl
      
      lea dx,fin_msg     ;prints out fin_msg
      mov ah,9           ;
      int 21h            ;
      
mov ah,8                 ;will cause the program to pause until the user presses any key
  int 21h
mov ah,4ch               ;return control to OS
  int 21h

;*******************
wait1: mov pause,0ffffh
agn1:  mov pause1,0ffffh
agn2:  dec pause1
       jnz agn2
       dec pause
       jnz agn1
   ret
;*******************
special:
       mov count,16      ;the number of chars to be moved
       mov di,0
star1: mov wStr+di,'*'   ;add 3 stars to the beginning of the line
       inc di
       cmp di,3
       jne star1
agn:   add di,si         ;copies the values from in_str to wStr with the specific offset from si register
       sub di,3
       mov dl,in_str+di
       sub di,si
       add di,3
       mov wStr+di,dl
       inc di
       dec count
       jnz agn
star2: mov wStr+di,'*'   ;add 3 stars to the end of the line
       inc di
       cmp di,22
       jne star2
   ret 
;*******************       
chrfix:mov cx,p-1         ;method that fixes extra chars that stick to the beginning of a string
       mov si,2           ; ! warning ! 
fix:   mov al,in_str+si   ; method cannot be nested!
       mov in_str+si-2,al ;
       inc si             ;
       loop fix           ; 
   ret
;*******************
cls:   mov cx,25          ;method that clears the screen
top:   mov ah,2           ; ! warning ! 
       mov dl,10          ; method cannot be nested!
       int 21h            ;
       loop top           ;
   ret
;*******************   
newl:  mov ah,2           ;method that moves the cursor to the next line
       mov dl,10          ;drop 1 line
       int 21h            ;
       mov dl,13          ;go to start of line
       int 21h            ;
   ret
    
end