;This program recives a string input from the user and "corrects" it - first letter becomes upper case, all others become lower case
.model small
.stack 100h
.data
                                        
p = 50                  ;maximum string support: 49 chars

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

init: mov ax,@data
      mov ds,ax 
      mov ax,3
      int 10h
      
      lea dx,st_msg      ;prints out st_str
      mov ah,9           ;
      int 21h            ;
      
      lea dx,in_str      ;read in_str
      mov ah,0ah         ;
      int 21h            ;
      
      call chrfix
      call newl
      
      mov si,0
      cmp in_str+si,'@'  ;first char is @, skip all steps
      je done
      
      cmp in_str+si,'a'  ;first letter is already upper case, skip next step
      jb lower           ;
      
      sub in_str+si,32   ;will cause the first letter to become upper case

lower:mov cx,p-2         ;check the entire string
agn:  inc si             ;
      cmp in_str+si,' '  ;skip checks for special chars (space, line feed)
      je low             ;
      cmp in_str+si,0dh  ;
      je low             ;
      cmp in_str+si,'Z'  ;checks for upper case
      jae low            ;
      add in_str+si,32   ;turns upper case to lower case
low:  loop agn           ;
      
done: lea dx,in_str      ;print out the fixed in_str
      mov ah,9           ;
      int 21h            ;
    
      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
;*******************
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
;*******************   
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