The programs that make the characters act on their own, run by 976C. Every character has a pointer (in its entry in C9BA) to where it has got to in its program, and a reaction table. Each comment below decodes one instruction.

HOW THE PROGRAMS RUN. On each of its turns a character works through its program until one instruction succeeds; that ends its turn, and next turn it carries on from the following instruction. An instruction that fails either falls through to the next one, or, if it has an 'if it fails go to' address, jumps there, in the same turn. A character gives up after six failures in one turn. 'Go to' instructions do not use up a turn. Actions without a target or instrument let the game choose suitable objects, exactly as it does for the player's commands, so 'attack' means 'attack whoever is here' and 'take' means 'pick up something'.

Instruction formats (the low nibble of the first byte is the type; bit 4 means a failure address follows, bit 5 'once only', bit 6 'no orders from the player here'):

Bytes	Instruction
t, action, target, instrument	do an action with those objects ($FF = let the game choose)
t+1, address, 0	call a special routine (the routines in A406-A91B)
4, action	do an action and let the game choose any objects; action $FF means 'do nothing this turn'
$0E, address	go to
$0C, action	switch to the reaction for that action
$0F, n	switch to a randomly chosen entry of the reaction table
other	switch to the default entry of the reaction table and end the turn

REACTION TABLES are lists of 3-byte entries ending with $FF: an action and a program address. When something is done to a character, the entry for that action (if any) becomes its program (99FB); entries with action 0 are the default behaviours, used by 'switch to a random behaviour'. In memory each character's reaction table comes straight before its program (the goblins' three tables come first, together); the headings below mark where each table and each program begins. Common reactions are shared: C94D is the general 'fight back' program (attack; attack again; run; repeat, or follow the attacker if it runs), C96E the response to being given something ('thank you' or 'what do you expect me to do with this?'), and C962 the response to being captured (go through an exit or door if possible, otherwise run).

WHAT THE CHARACTERS DO:

• Gandalf (C7A9) begins by giving Bilbo the curious map and opening the round green door. After that he is a random wanderer: five little routines (C7B1, C7BF, C7C3, C7C9, C7CD) chosen at random make him run about, pick things up and ask 'what's this?', drop or give things away, open and close doors, and make small talk.
• Thorin (C7DB) follows Bilbo whenever he can. When he cannot, he picks up the small curious key if he finds it (saying once 'this was thrains key'), asks 'where's the thief?' if Bilbo is invisible, or runs through his idle routine (A550): wait, 'hurry up', or sit down and sing about gold.
• The wood elf (C80C) wanders at random capturing anyone it meets, who ends up in the Elvenking's dungeon (A316).
• The warg (C817) attacks anyone it can; otherwise it follows its prey, or runs around Bilbo howling (A4CA), or runs off.
• The butler (C83F) acts out the story from the book: he unlocks the red door with the red key, opens it, shuts it and locks it again; he opens a barrel and drinks the wine, closes the barrel, opens the trap door, throws the barrel through it into the river, and closes the trap door - capturing any intruder at every opportunity - and then starts again.
• Elrond (C889) greets Bilbo when he arrives and gives him lunch (A8D9), and otherwise waits.
• The dragon (C8A7) sleeps on the treasure until it is taken (A5D5); then, as long as the dragon itself is somewhere lit, each turn there is about a 1 in 6 chance that it descends and burns Bilbo to a crisp, otherwise 'in the distance you see the shape of a monstrous dragon flying after you.' Before that, if Bilbo comes into one of its three rooms it flies to him (A591), speaks (A5BB) and burns him.
• Bard (C8CD) does nothing on his own: he waits for an order from the player (A79F), and then repeats that order every turn. His reaction to being attacked is to SHOOT (C8D8).
• Gollum (C8E6) asks his riddle when he meets Bilbo (A7C6), and kills him if the answer is wrong (A7EA); he mutters about his precious (A81A), paces north and south-west, drops and picks up the golden ring, and if attacked puts the ring on, becomes invisible and runs.
• The trolls (C92A) wait until Bilbo comes into the clearing and then say their lines (A8B1). After that their program is: try to eat Bilbo, wait, eat, wait, eat, wait, eat, and then dawn (A865), which turns them to stone. So after the trolls have spoken, Bilbo must be out of the clearing on the turns they try to eat him; waiting outside for the new day dawning (as the HELP message says) is the way.
• The goblins patrol set routes (for example C731: open the small insignificant crack, go up, down, close the crack, south, north), capturing anyone they meet on the way, who ends up in the goblins' dungeon; the last three goblins (C784) just run about attacking and capturing.

One instruction in this area is changed during play: A79F rewrites the instruction at C8D1 to hold Bard's latest order, which is why SAVE and LOAD take care to save three of its bytes (8284).