98a

; Example of how to write directly to screen memory, instead of
; using the *slow* BIOS function calls.
; Note: uses the DIRWR.PRC module, which must be included at assembly time.

        jmp start


strgs1:  db ' This is a test of writing directly to screen '
len1 equ $-strgs1 
         db ' It shows the obvious difference in speed     '
         db ' comparing to writing with BIOS...            '
         db ' Since the adress of screen memory is at      '
         db ' B800:0000 it is rather simply achieved.      '


strgs2: db ' Here is some more text '
len2 equ $-strgs2
        db ' Nice, Huh?             '
        db ' It is so easy...       '
       

strgs3: db ' And here is even more text '
len3 equ $-strgs3
        db ' Note the change in attri-  '
        db ' butes from box to box!     '
        db ' It is fantastic. And so    '
        db ' simple!                    '





length dw 0


start:
        call clrscr             ;Clear Screen

        mov cx,5                ;Number of lines               
        mov bl,1DH              ;Attribute
        mov dh,10                ;Row
        mov dl,10               ;Column
  

        mov si,strgs1           ;Adress of string to output
        mov length,len1

        call outstrings


        mov cx,3                ;Number of lines               
        mov bl,2EH              ;Attribute
        mov dh,0                ;Row
        mov dl,0                ;Column
  
        mov si,strgs2           ;Adress of string to output
        mov length,len2

        call outstrings



        mov cx,5                ;Number of lines               
        mov bl,3FH              ;Attribute
        mov dh,18               ;Row
        mov dl,50               ;Column
  
        mov si,strgs3           ;Adress of string to output
        mov length,len3

        call outstrings



        mov ah,00H              ;Wait for key
        int 16H


        call clrscr             ;Clear screen

        
        int 20H                 ;Exit to DOS



outstrings:
again:
        push cx

        mov cx,length           ;Length of string
        call write_str        

        inc dh                  ;One row down
        add si,length           ;Point si to next string
        pop cx
        loop again              ;Here we go again...

        ret

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