Interpreter cycle

The interpreter cycle in AGI works thusly:

                         +---------------------------+
                         |      1. delay time        |
                         +---------------------------+
                                       |
                                       V
                         +----------------------------+
                         |2. clear the keyboard buffer|
                         +----------------------------+
                                       |
                                       V
                         +---------------------------+
                         |      Flag (2) - > 0       |
                         |      Flag (4) - > 0       |
                         +---------------------------+
                                       |
                                       V
                    +-------------------------------------+
                    | 3. poll keyboard and joystick       |
                    +-------------------------------------+
                                       |
                                       V
                    +-------------------------------------+
                    | If the current mode is              |
                    | - program_control, the direction of |
                    |   Ego motion <-- var(6).            |
                    | - player.control, var (6) --> dir.  |
                    |   of Ego motion.                    |
                    +-------------------------------------+
                                       |
                                       V
    +---------------------------------------------------------------+
    | For all objects for which command animate.obj, start_update   |
    | and draw were carried out, the recalculation of the direction |
    | of movement is performed.                                     |
    +---------------------------------------------------------------+
                                       |
                                       V
    +---------------------------------------------------------------+
    | If the score has changed (var (3)) or the sound has been      |
    | turned on or off (Flag (9)), the status line is updated.      |
    +---------------------------------------------------------------+
                                       |
                                       +---------+
                                                 V
                                   +--------------------------+
                 +---------------->| 4 Logic 0 is executed    |
                 |                 +--------------------------+
                 |                               |
                 |                               V
                 |          +--------------------------------------+
                 |          | - Dir. of motion of Ego  <-- var (6) |
                 |          | - If score (var (3)) or Flag (9)     |
                 |          | have changed their values - update   |
                 |          | the status and score (on Var (3));   |
                 |          | - Var (5) - > 0;                     |
                 |          | - Var (4) - > 0;                     |
                 |          | - Flag (5) - > 0!!!!                 |
                 |          | - Flag (6) - > 0;                    |
                 |          | - Flag (12) - > 0.                   |
                 |          +--------------------------------------+
     +----------------------------+               |
     | Execute:                   |               V
     | ~~~~~~~~~~~~~~~~~~~~~~~~   |  +------------------------+
     | - stop.update;             |  | Update all controlled  |
     | - unanimate.all;           |  | objects on the screen. |
     | - destroy all logic        |  +------------------------+
     |   resources except         |                   |
     |   for logic 0;             |                   V
     | - player.control;          |            +--------------+
     | - unblock;                 |            | new.room n   |
     | - set_horizon 36;          |            | or           |
     | - var (1) = var (0);       |            | new.room.v n |
     | - var (0) = n | Var(n);    |            | was issued?  |
     | - var (4) = 0;             |            |              |
     | - var (5) = 0;             |            +-------+------+
     | - var (9) = 0;             |<-----------+  Yes  |  No  |
     | - var (16) = number of     |            +-------+--+---+
     | view assoc. w/Ego;         |                       |
     | - Ego coords from var (2); |                       |
     | - var (2) = 0;             |                       |
     | - flag (2) - > 0;          |                       V
     | - flag (5) - > 1!!!!       |               +--------------+
     | - score < - var (3);       |               | Go to step 1 |
     +----------------------------+               +--------------+

Resources

• AGI Internals