Used by the routine at CHE3D.

The author's I6: the rest of the dispatch that CHE3D (CHE3D) begins, which tests the low nibble of the object's state (+14) in turn and comes here for state 6 and up. Each case chooses a direction in C and a sprite in HL, and leaves by one of three doors into the movement code: ANIM (in KNIGHT_CONTROLS), which picks a frame from a run of them, SET_SPRITE_AND_MOVE (ANIMATE_AND_MOVE), which shows HL as it is, or MOVE_IN_DIRECTION (ANIMATE_AND_MOVE), which leaves the sprite alone. From there the object is moved in direction C, collides, lands, and is redrawn.

The states handled here, with the object types whose templates (TEMPLATES) start them in each: 6 and 10 (types 26 and 33): a guard. Within 30 of the knight along the floor it chases him (STEER); further off, a state-6 guard walks to and fro along x and a state-10 one along y, turning back at whatever stops it. Its frames depend on the way it walks: SPRITE9F3C, SPRITEA110, SPRITEA554 or SPRITEA728, three each. The guards of state 9 (type 27), which materialise first (CHE3D), use the same frames and always chase. 7 (type 13): the troll, which chases, turning its frames (SPRITE8BB8 facing the viewer, SPRITE8E64 facing away). 11 (type 45): a wraith, which chases and has one frame each way, SPRITE5E88 and SPRITE5F08. 12 (type 51): hangs in the air where it is and flickers through three small frames from SPRITE5B00. 13 (type 52): wanders, diagonally if it has no way of its own yet, and turns back off whatever it meets; frames from SPRITE5B30. 14 (type 40): hangs where it is and flickers through three frames from SPRITE6104. 15 (type 56, one in room 61): stands still until the thing of kind 11 lies in the room, when it takes the wraith's frames and state and chases the knight from then on (measured: it becomes state 11 for good). The door out of room 61 waits for the same thing (BUMPED). 8: the knight -- KNIGHT_UPDATE, below. Any other (1 or 2, which no object that is updated has): moves the way +13 says, with no sprite change.

The knight (the author's I8, KNIGHT_UPDATE) comes here on every pass on which he is not in the air: in the air, CHE3D carries him on in the direction +18 holds. First, if he has just landed from a long fall, it costs him LIFE: IY+$14 counts the passes he fell for, and each pass over 20 -- each two units over 40 -- takes a point (measured: a fall of 50 cost 5, of 60 cost 10, of 40 nothing). Then the keys. Any key but the number keys goes to the action keys: X to V pick up (PICK_UP), CAPS SHIFT and Z drop, and the rest walk, jump and fight (KNIGHT_CONTROLS). With no key, the Kempston joystick (when 9 has turned it on) goes to KNIGHT_CONTROLS too. With neither, he stands: facing the viewer or away, with now and then a fidget of 14 passes (bit 3 of IY+$17) after a random wait of 128 to 255.

The drop (Krumlinde's MainLoop_DropItemCheck, at the CAPS SHIFT row test) takes the thing in the place in use and puts it down just beside him on the side he faces: past his own width or depth when he faces the way the axis grows, past the thing's own when he faces back. Its top is set level with his, so it starts in the air. If the thing's box there meets anything (FIND_OBSTACLE), BLOCKED (message 1, IY+$07) and nothing changes. Otherwise the place is emptied, the thing moved there, its weight -- its +16 less 16, and never below nought -- taken off CARRIED_WEIGHT (IY+$12), its carried flag cleared, and it is given one pass going up (state bit 4 with +13 = $12) after which it falls to the floor like anything else. The object table is told it is in this room now (SET_THING_ROOM) and the panel's box for the place is emptied (CLEAR_THING_BOX). With 46 or more object records in use the drop key is ignored (not worked out why).