100H: /* TWO'S COMPLEMENT                                                   *?

   /* CP/M BDOS SYSTEM CALL */
   BDOS: PROCEDURE( FN, ARG ); DECLARE FN BYTE, ARG ADDRESS; GOTO 5;END;
   /* CONSOLE OUTPUT ROUTINES */
   PR$CHAR:   PROCEDURE( C ); DECLARE C BYTE;    CALL BDOS( 2, C ); END;
   PR$NL:     PROCEDURE; CALL PR$CHAR( 0DH ); CALL PR$CHAR( 0AH );  END;
   PR$HEX: PROCEDURE( B ); /* PRINTS B AS A 2 DIGIT HEX NUMBER */
      DECLARE B BYTE;
      DECLARE D BYTE;
      IF ( D := SHR( B, 4 ) ) > 9 THEN CALL PR$CHAR( ( D - 10 ) + 'A' );
                                  ELSE CALL PR$CHAR(     D      + '0' );
      IF ( D := B AND 0FH   ) > 9 THEN CALL PR$CHAR( ( D - 10 ) + 'A' );
                                  ELSE CALL PR$CHAR(     D      + '0' );
   END PR$HEX ;

   DECLARE A  BYTE;

   A = 1;
   CALL PR$HEX( A );
   CALL PR$CHAR( ' ' );
   A = -A;
   CALL PR$HEX( A );
   CALL PR$NL;

EOF