print a string on two different lines

Question

I am trying to get my program to display a string on two different lines.

This is a .com program and I am using A86 assembler.

jmp start               ; This will start the program

;============================

  msg   db  "Hello Word.$"      ; A string variable 
  msg   db  "Michael J. Crawley$"   ; A string variable with a value.

;============================

start:

  mov ah,09             ; subfunction 9 output a string

  mov dx,offset msg         ; DX for the string

  int 21h               ; Output the message

  int 21h               ; Output the message

exit:

  mov ah,4ch
  mov al,00             ; Exit code 

  int 21h               ; End program

Solution 1

Here are your specific problems:

• You define msg twice (a86 will barf on that).
• You call int21 fn9 with the same value of msg so you're not printing the two messages out, just two copies of the first.
• You don't have a newline character in either message so they'll abut each other rather than be on separate lines.

The solutions to those points (without providing the actual code).

• Label the second message as msg2.
• Load msg2 into dx before calling int21 for the second time.
• Change the messages to put a newline before the '$' symbol (or at least the first one).

---

Update: Since some other helpful soul has already provided source, here's my solution. I would suggest you learn from this and modify your own code to do a similar thing. If you copy it verbatim from a public site for classwork, you'll almost certainly be caught out for plagiarism:

         jmp start                   ; This will start the program

msg      db  "Hello Word.",0a,"$"    ; A string variable .
msg2     db  "Michael J. Crawley$"   ; A string variable with a value.

start:   mov ah,09                   ; subfunction 9 output a string
         mov dx,offset msg           ; DX for the string
         int 21h                     ; Output the message
         mov dx,offset msg2          ; DX for the string
         int 21h                     ; Output the message
exit:
         mov ah,4ch
         mov al,00                   ; Exit code 
         int 21h                     ; End program

This outputs:

Hello Word.
Michael J. Crawley

Solution 2

Two definitions of msg?

Comments

[Michael]

I am not sure I understand. Should I remove one.... db "Michael J. Crawley$" ; A string variable with a value.

[Michael Burr]

Don't DOS int21 calls return a result code in AX as well so it would have to be reloaded before the 2nd call? Or did DOS just set the carry flag to indicate an error.

[paxdiablo]

@Michael, not fn9, it returns nothing.

[Ponkadoodle]

@Mike: No, they each need unique names. You could replace the first "msg" with "msg1", and the second with "msg2".

[Michael]

No... I am not a copy paste kind of guy I actually want to learn this. I will try it.

[Michael]

0a is the placement of the string?

[paxdiablo]

@Mike, 0a is the hex code for a newline (ASCII 10) character. int21/fn9 will intepret this as a request to drop down to the start of a new line.

[paxdiablo]

This is why a86 is so good and why Harald is so rightly arrogant :-) It will assemble a file without any of the gumpff required by other assemblers - I always hated masm and it's requirement that I had to provide 25 lines of administrivia just to do a 5-line hello world program. Turbo Assembler took away a lot of that but a86 goes all the way.

[User.1]

Be aware, you might also need a 0Dh byte along with the 0Ah byte to do a complete new line and carriage return