PL/M-86

$TITLE('Simple PL/M-86 Example')
$PAGEWIDTH(80)
EXAMPLE: DO;
  DECLARE STRING LITERALLY 'Hello, World!';

  /* Simple procedure to output a character */
  OUTPUT$CHAR: PROCEDURE(C);
    DECLARE C BYTE;
    /* Output to console port */
    PORT[0E9H] = C;
  END OUTPUT$CHAR;

  /* Output string procedure */
  OUTPUT$STRING: PROCEDURE(S);
    DECLARE S ADDRESS;
    DECLARE I BYTE;
    DO I = 0 TO LENGTH(STRING) - 1;
      CALL OUTPUT$CHAR(STRING(I));
    END;
  END OUTPUT$STRING;

  /* Main program */
  CALL OUTPUT$STRING(@STRING);
END EXAMPLE;