Event Script Opcodes

Event Script Opcodes

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This note decodes the bytecode dispatcher used by the event.dat script section.

[TOC]

Derived from:

• dispatch loop at 0x172CA / 0x1750C
• opcode jump table at 0x17494
• handler stubs at 0x172D8..0x17484

Core Behaviour

• Bytecode opcodes are in range 0x00..0x32.
• 0xFF terminates a script block.
• Invalid opcodes branch to 0x1748C and set abort flag A4-$8616.
• After each opcode, control returns to 0x1750C to fetch next byte.

Verification Against ASM (cross-checked)

The following were re-confirmed directly from mm2.capstone.asm:

• Tile-event scanner 0x1754A: triplet table is 3-byte groups (pos, event, cond) read from offset 0, terminated by the first 00 00 00 group. String-table offset = (terminator+3) + str_rel_word; script PC start = terminator+5. This matches decode_event.decode_location exactly.
• Position byte = (row<<4)|col i.e. (y<<4)|x (0x17608-0x17618), confirming the (y,x) trigger order.
• Cond byte is AND-masked with the direction/context byte and the event is skipped when the result is zero (0x17682 and.b + beq).
• Event id selects a record in one 0xFF-delimited pool (skip loop at 0x17262). The pool mixes opcode scripts and plain-text records.
• Dispatch 0x172CA -> table 0x17494; valid opcode range 0x00..0x32 (cmp.l #$33 at 0x174FA).
• argc fix: OP_03 reads 1 byte (was previously logged as 0).
• Special records: locations 63, 65, 68 contain no 00 00 00 terminator and are not processed by the tile-event scanner (castle / Hall-of-Spells style data); the decoder now flags these as unreliable.

Opcode Table (Current Decode)

argc is inferred from read_u8/read_u16/read_u24 helper usage in each handler.

Op	Handler	argc	Notes
00	0x1748C	0	invalid/abort
01	0x15924	1	show text; u8 string index (via 0x15884->0x155BE)
02	0x15942	1	show text block; u8 string index (stub also pushes const 0x13)
03	0x159CE	1	show text; calls 0x15942 (const 0x11) which reads u8 string index
04	0x159F4	1	show text above door; u8 string index
05	0x15A46	1	show text popup A; u8 string index
06	0x15AEE	1	show text popup B; u8 string index
07	0x15CE6	0	wait-loop until SPACE key, then continue
08	0x15D26	0	wait for key (sets cursor mode 0xFD, calls wait helper 0x15CE6)
09	0x15D3C	0	y/n prompt, writes result into condition flag
0A	0x15D9A	0	y/n prompt variant (mode 0xFD, calls 0x15D3C)
0B	0x15DB0	2	open service/title window (u8 string via 0x15756, u8 position)
0C	0x15E12	2	map transition to (u8 dest, u8)
0D	0x15EC4	1	u8 -> engine thunk -$7E42 (generic engine call)
0E	0x160C2	1	selector dispatch (see selector table below)
0F	0x162A6	0	end/return script (sets stop flag, calls cleanup 0x171AC)
10	0x162B8	var	IF(cond) skip N token-stream entries
11	0x162DC	var	IF(!cond) skip N token-stream entries
12	0x16300	12	encounter/combat setup: 10-byte block + 2 bytes (dispatch pushes 0)
13	0x16386	10	encounter setup variant (calls 0x16300 with flag=1, 10-byte block)
14	0x16398	0	clear current tile event high-bit / clear runtime event flag
15	0x16426	3	apply state to party members (u8 count, u8, u8; 4th byte only when flag=1)
16	0x16520	2	scan up to 6 monster slots; set cond if field +0x3A/+0x28 matches arg2
17	0x165A4	2	load condition byte from resolved variable pointer
18	0x165C6	4	OP_15 handler with flag=1 (u8 count, set, and, or) -> masked party apply
19	0x165D8	4	add entity to party/roster (writes fields +0x3A/+0x40/+0x46)
1A	0x166F8	2	store u8 into resolved variable pointer
1B	0x16724	1	clear cond unless cond >= u8 (threshold gate)
1C	0x16742	1	engine query -$7BB4(1, u8) -> cond
1D	0x16762	1	engine call indexed by u8*7+1 (-$7E84)
1E	0x16780	1	timed wait/delay loop for u8 iterations (-$7BC0/-$7BD2)
1F	0x1690E	6	apply effect to party members (selector + values via 0x167B0)
20	0x16A22	6	party-effect variant (calls 0x1690E with mode=1)
21	0x16A34	3	set tile data at (y,x) (arg1 nibbles) into arrays -$55BA/-$54BA
22	0x16A9E	2	set condition if current era (-$79B5, low byte of era word) is in [lo, hi] — era/time-range gate
23	0x16ADA	2	reads day-of-year (-$79DE[era]) and range-checks it (calendar/day gate)
24	0x16B54	2	check u16 gold amount -> condition flag (strong evidence)
25	0x16B82	2	check non-gold 16-bit code -> condition flag (hi,lo bytes)
26	0x16BC0	0	prompt to select a party member (ESC 0x1B ends script)
27	0x16BC0	0	select-party-member variant (input mode 1)
28	0x16C86	2	consume item id (arg1) from party inventory -> condition flag
29	0x16D08	0	force abort/exit flag
2A	0x16D16	14	set treasure/reward block: u24 gold/exp, u16 gems, 3x(id,?,?)
2B	0x16D74	var	u8 + token-skip walk
2C	0x16D98	1	add u8 to state var -$79B8, flag redraw
2D	0x16DBA	2	check party-member attribute (arg1 bits select fields +0xC/+0xE/+0xF) -> cond
2E	0x16F50	2	set attribute bit (or arg2) on matching party class -> field +0x51
2F	0x16FEA	0	clear/space-fill input buffer -$5C50
30	0x17034	10	answer/password check: 10 bytes vs player input; char = 0x11A - byte (0xFA=space)
31	0x170BC	3	iterate target party members and call engine op
32	0x17190	1	load condition from script variable id

Notes on *_SKIPTOK Opcodes

Opcodes 0x10, 0x11, and 0x2B call token skip helper 0x157FC. That helper:

1. Reads a count byte.
2. Repeats count times:
   • reads current token byte from script stream,
   • looks up token length delta in table at A4-$6CC8,
   • advances script pointer by that delta.

So these opcodes are deterministic but variable-length and need token table support for full static disassembly.

Text Display Opcodes (OP_01–OP_06)

All six read a u8 string index via 0x15884 → 0x155BE, copy the resolved string into the draw buffer at A4-$5D3C via 0x158C8 (which maps @ / 0x40 to newline 0x0A for the renderer), then paint. Font: 8×8 bitmap font 8 (EXTRACTED/fonts/mm2/8); atlas export editor/assets/fonts/mm2_8.png / mm2_8.json via tools/export_mm2_bitmap_font.py.

Op	Handler	Typical use (from event.dat usage)
01	0x15924	Basic one-shot message; sets exit-flag bit 0 (A4-$7950); draws via -$7EC0
02	0x15942	Multi-line text block; sets exit-flag bit 1; positions with -$7F62/-$7BFC, draws glyphs via -$7C62 until 0x0A or 0xFF
03	0x159CE	Prep (-$7F5C, -$7ED8) then delegates to OP_02 with window height const 0x11
04	0x159F4	Door label — centered caption above a door tile; single -$7BE4 text draw after width centering
05	0x15A46	Popup A — large plain overlay (see below)
06	0x15AEE	Popup B — framed sign popup (see below)

Popup A vs Popup B (OP_05 / OP_06)

Both handlers skip all drawing when A4-$79E1 (can't-see / darkness overlay) is non-zero — same gate as OP_04.

OP_05 @ 0x15A46 — plain overlay (Popup A)

• Allocates a text window via -$7C74(4, 3, 24, 13) → (x, y, w, h) in character cells (large, borderless).
• One -$7BE4 text draw of the full string into that window.
• Vertical position is adjusted by party facing: calls 0x1582e (counts wrapped text lines from 0x0A newlines and 14-char rows), halves the count, and if the result is < 5, shifts the window up by (4 − lines) via -$7BFC.
• Observed content: longer narrative plaques — missing-person posters, quest hints, arena notices, radiation warnings (~40 uses in locations 0–59).

OP_06 @ 0x15AEE — framed sign (Popup B)

• Preprocesses the string in place: every - (0x2D) is rewritten to { (0x7B, full-width horizontal bar glyph) before draw.
• Smaller window -$7C74(8, 8, 18, 9).
• Draws a UI border by blitting font control glyphs through -$7C62: 0x10/0x11 top corners, 0x0E ×11 top bar, 0x14/0x15 sides with -$7BE4 text column between, 0x7E fill tiles, 0x12/0x13 bottom corners, 0x0F ×11 bottom bar (see control-glyph table below).
• Observed content: compact directional signs and town labels with arrows and $ bullet markers (~110 uses) — e.g. "< Shortcut\nPinehurst", "Woodhaven$\n<Tundara", "Dead Zone\nRadiation!".

OP_04 vs popups in practice: OP_04 is the shop/door nameplate fixed above a door (dominant in town maps — often paired with OP_0B service window and OP_0E shop selector). Use OP_05 for long read-once lore/warning text without a frame; OP_06 for short outdoor signposts that need a visible border and decorative rules/arrows; OP_04 strictly for door labels on building entrances.

MM2 8×8 Text Format Characters

Reference atlas: editor/assets/fonts/mm2_8.png (128×64, 16×8 cells, codepoints 0x00–0x7F). Strings in event.dat are 0xFF-terminated on disk. The copy helper 0x158C8 converts @ (0x40) → 0x0A for rendering; decoded tool output may show either form — see 06-event-dat-format.md.

Control glyphs (0x00–0x1F) — UI chrome (drawn via -$7C62, especially Popup B border builder @ 0x15AEE):

Code	Char	Role
0x0A	(LF)	Full-frame box tile (also newline in text streams)
0x0E	(SO)	Top horizontal bar
0x0F	(SI)	Bottom horizontal bar
0x10	(DLE)	Top-left corner
0x11	(DC1)	Top-right corner
0x12	(DC2)	Bottom-left corner
0x13	(DC3)	Bottom-right corner
0x14	(DC4)	Left vertical side
0x15	(NAK)	Right vertical side / interior column pad

Other control codes in 0x00–0x0F are present in the atlas but are not used by the Popup B border prologue; they may appear in other UI thunks (OP_02 glyph loop, service windows).

Printable format characters in event strings (especially OP_06 signs):

Code	Char	Visual / behaviour
0x2D	-	Thin dash in source; OP_06 only rewrites to 0x7B before draw
0x7B	{	Full-width horizontal bar (decorative rule)
0x5B	[	Left arrow (same glyph as <)
0x3C	<	Left arrow
0x5D	]	Right arrow (same glyph as >)
0x3E	>	Right arrow
0x24	$	Diamond / bullet marker
0x7E	~	Solid block (also used as border fill in Popup B)
0x5F	_	Underline bar
0x40	@	Line break (stored in strings; renderer sees 0x0A)

Semantics Confirmed in This Pass

• 0x22 (0x16A9E) range-checks current era (A4-$79B5 low byte) against script [lo, hi] args and writes boolean to condition flag A4-$7951.
• 0x10/0x11 branch via token-skip helper 0x157FC, gated by A4-$7951.
• 0x14 clears current tile's visited/event bit in A4-$54BA and clears runtime flag byte A4-$55D6 bit 7.
• 0x29 sets abort flag A4-$79EA = 1.
• 0x32 copies a variable byte (via engine thunk -$7F2C) into condition flag A4-$7951.

OP_0E Selector Dispatch (0x160C2)

OP_0E reads one selector byte and runs a chained-subtraction switch:

• Explicit cases call dedicated engine thunks:

  • 1 tavern/food, 2..8 other town buildings (each a distinct -$7Dxx thunk),
  • 100 (0x64), 126..131 (0x7E..0x83), 201..207 (0xC9..0xCF), 226 (0xE2), 253 (0xFD) are further specials (travel/portal/quest handlers).

• Default (any other selector) -> 0x15EDC, which bins the selector into a service category using engine range-check -$7E9C and calls town handler -$7DFA:

  selector range	category byte	adjusted index base
  0x09..0x10	0x3C	-8
  0x11..0x37	0x3D	-0x10
  0x38..0x4B	0x3E	-0x37
  0x4C..0x54	0x3F	-0x4B
  0x56..0x5B	0x40	-0x55
  0x5C..0x5E	0x41	-0x5B
  0x65..0x69	0x42	-0x64
  0x6A..0x7C	0x43	-0x69
  0x97..0x98	0x44	-0x96
  0xE3..0xF3	0x45	-0xE2
  0xF4..0xFB	0x46	-0xF3

Gameplay-observed selector meanings (shops/temple/training/guilds) live in the SELECTOR_NAMES map in tools/decode_event.py. Per-town tiles, strings, donation quest, blacksmith specials, and training HP formula: 28-town-services.md.

OP_30 Answer Check (Verified)

OP_30 stores a 10-byte expected answer inline, encoded as byte = 0x11A - ascii (0xFA = trailing space). Decoded answers found in event.dat:

• "MEENU", "KEYS" (matching user-reported answer words), and numeric combination codes "46", "23", "64", "32".

Disassembly Alignment Check

After the argc corrections (OP_12=12, OP_13=10, OP_15=3, OP_18=4, OP_30=10), a linear walk of every real script segment now consumes each segment exactly: 0 overruns, 0 underruns (excluding token-skip and text records). Previously there were 35 underruns from the wrong arg counts.

Atlantium (Location 1) — User-Verified Examples

• Shop/sign tiles (Carriage Inn, Drewnhald Ironworks, Boar's Tongue Tavern, etc.):

  • Behavior: text only, retriggers when stepping onto tile again.
  • No immediate movement/state side effect observed.

• Arena gate:

  • Without ticket: message shown ("Sorry, but you must have a ticket to compete in these games.").
  • With ticket: immediate combat starts.
  • Post-fight: returned to same gate area.
  • Retrigger rule: step off and back onto trigger tile.
  • Ticket is consumed per fight.
  • Script chain in this location uses item-check style ops (0x24 / 0x25) around gate logic, consistent with ticket gating.

• Olympic Trial:

  • Current observed behavior: text only ("Hurl the spear..."), no immediate combat/transition.

Global Ticket/Key Model (User-Verified)

• There are 4 ticket items in items.dat (color-coded):
  • green
  • yellow
  • red
  • black
• There are 4 key items (town-purchased), used to free bishops in castles.
• Arena world model:
  • Arenas exist in Middlegate, Atlantium, Sandsobar.
  • Tundra has no tickets.
  • Volcania uses the red ticket line.

Reverse-Engineering Implications

• OP_24 is strongly indicated as a gold check opcode (not item-id):
  • observed args include 10, 25, 50, 200, 500, matching common payment gates.
• OP_25 is a non-gold 16-bit predicate path (small observed codes 0/1/2 so far).
• Arena gate blocks likely follow:
  • predicate (OP_24/OP_25) -> condition flag
  • conditional skip (OP_10/OP_11)
  • combat/arena transition call
  • ticket consumption side effect
• Castle bishop gates should provide additional traces for key-specific checks using the same opcode family.

OP_24/OP_25 Evidence Snapshot

Extracted OP_24 arguments across locations:

• 0x000A (10) — Middlegate flow
• 0x0019 (25) — Atlantium flow
• 0x0032 (50) — Tundra/related flow
• 0x00C8 (200) — Sandsobar/related flow
• 0x01F4 (500) — Atlantium travel/training flow

These values align with payment-style prompts and are unlikely to be item IDs.

Observed OP_24 contexts (decoded segments):

• 0x000A (10): Middlegate mapper/travel style prompt flow.
• 0x0019 (25): Atlantium branch in arena/shop event chain.
• 0x0032 (50): Atlantium/Vulcania travel prompt family.
• 0x00C8 (200): training/skill purchase flow.
• 0x01F4 (500): larger payment gate.

Observed OP_25 contexts:

• decoded values now include 0x0000, 0x0001, and 0x0002 (after endian correction).
• remaining None hits are in segments where token alignment is still uncertain after variable-length skip-token control flow.

Current best model:

• OP_24: gold predicate (amount check to condition flag).
• OP_25: non-gold code predicate (likely word/flag/class/item-code family).
• OP_28: consume-item path; maps cleanly to multiple quest items/keys/discs.

User-verified gate behavior supporting this model:

• bishop key gate: missing key -> blocked with message
• bishop key gate: with key -> allowed and key consumed
• arena tickets: consumed per fight

Tooling

Use the decoder's predicate extraction mode:

python tools/decode_event.py --predicates EXTRACTED/event.dat

--predicates now runs a path-aware, heuristic walk across OP_10/11/2B skip-token branches so predicate checks behind those branches are surfaced for review.

Use consume-item extraction mode:

python tools/decode_event.py --consumed EXTRACTED/event.dat --items items.dat --answers druids meenu keys

This reports:

• OP_28 consume hits with mapped item IDs/names
• per-location context strings
• string hits for candidate word answers (druids, meenu, keys)

This prints every parsed OP_24/OP_25 hit with:

• location + segment id
• decoded argument value (if recoverable)
• nearby opcode context
• nearby strings for gameplay correlation

Opcode Verification Status (gap inventory)

Classification: Verified = dispatch + core behaviour confirmed from ASM (and often gameplay); Partial = structure/argc known, gameplay semantics incomplete; Unknown = behaviour not traced.

Op	Status	Gap summary
00	Verified	Invalid opcode → abort
01	Partial	Basic text draw (-$7EC0); when used vs 02/03 in scripts unclear
02	Partial	Multi-line glyph loop via -$7C62; window mode const 0x13
03	Partial	Engine prep then OP_02; exact prep thunks unmapped
04	Verified	Door label above door; skips if can't-see
05	Verified	Popup A — plain overlay, facing-adjusted
06	Verified	Popup B — framed sign, -→{ preprocess
07	Verified	Wait for SPACE
08	Partial	Wait for key; sets cursor mode 0xFD
09	Verified	Y/N prompt → cond_flag
0A	Partial	Y/N variant (mode 0xFD wrapper)
0B	Partial	Service/title window (-$7FBC/-$7FC2); arg2 position byte semantics
0C	Partial	Map transition (dest screen + packed entry coord); bit6 remap path
0D	Unknown	u8 index → generic thunk -$7E42; per-index effects untraced
0E	Partial	Selectors 1–8 = town services; 0x64/0xC9–0xCF/0xFD specials; default range bins 0x09–0xFB → category table only
0F	Verified	End script / cleanup 0x171AC
10/11	Partial	Conditional token skip verified; static disasm needs full -$6CC8 length table
12	Partial	10× monster slot bytes + 2 tail bytes → combat; tail meaning unknown
13	Partial	Same as 12 with internal flag=1 (10-byte block only)
14	Verified	Clear tile event / visited bit7
15	Partial	Apply byte to N party members via 0x163CA; op/val/mask semantics
16	Partial	Scan ≤6 roster slots; match field +0x3A or +0x28
17	Partial	Load script variable group/index → cond
18	Partial	Masked party apply (set/and/or bytes)
19	Partial	Add entity to party (+0x3A/+0x40/+0x46)
1A	Partial	Store u8 into script variable
1B	Partial	Clear cond unless cond >= threshold
1C	Partial	Engine query -$7BB4(1, u8) → cond
1D	Partial	Engine call table -$7E84 indexed by u8×7+1
1E	Partial	Timed delay loop (-$7BC0/-$7BD2)
1F/20	Partial	Party effect dispatcher 0x167B0; 6-byte payload; mode flag on 20
21	Partial	Write (y,x) tile bytes into -$55BA / visited -$54BA
22	Verified	Era range gate (-$79B5)
23	Partial	Day-of-year gate via -$79DE[era]; special cases at args 0xB5/0xB6
24	Partial	Gold predicate via 0x155DA + -$7E66; amounts 10/25/50/200/500 observed; exact compare op untested
25	Partial	Non-gold u16 code via -$7E66; decoded values 0/1/2 only
26/27	Partial	Party-member select; 27 uses alternate input path when arg mode=1
28	Partial	Consume item if present → cond; keys/tickets user-verified
29	Verified	Force script abort
2A	Partial	14-byte treasure/reward block (gold/exp, gems, 3× item triplets)
2B	Partial	Token skip only when A4-$77BD set (combat-related flag)
2C	Partial	Add to global counter -$79B8; sets redraw exit flag
2D	Partial	Check member attribute fields +0x0C/+0x0E/+0x0F
2E	Partial	OR attribute bits onto matching class field +0x51
2F	Verified	Clear input buffer -$5C50
30	Verified	10-byte encoded password check
31	Partial	Iterate party members matching mask; per-member engine call
32	Verified	Load cond from script variable id

Overlay locations 60–70 (see event_location_inventory.json): most are string_bank records (no tile scripts) referenced by index from other code; 63/65/68 are castle_blob (no 00 00 00 terminator); 67 is a mixed_pool with non-standard opcodes (0x41+) that are outside the 0x00–0x32 dispatcher — runtime trigger path for these banks is still partially traced (queued dispatch @ 0x176B6 vs standard scanner).

Gameplay confirmation quiz (pick A/B/C/D or correct us)

Answer key for the RE team — fill in Your answer: as you play-test. Options are mutually exclusive unless noted.

---

1. Text placement opcodes (OP_04 / OP_05 / OP_06)

Scenario: You step on an outdoor arrow sign vs a building nameplate vs a long quest plaque.

• A. OP_06 = framed signposts with arrows/rules; OP_05 = long borderless lore/warnings; OP_04 = door/shop labels only (never dungeon wall fluff).
• B. OP_05 and OP_06 are interchangeable; only string length differs.
• C. OP_04 is used for both doors and outdoor signs; OP_06 is dungeons only.
• D. OP_05 is the default signpost; you have seen it with arrow glyphs where we expect OP_06.

RE guess: A — event.dat usage (~110 OP_06 sign strings vs ~40 OP_05 plaques; OP_04 clusters on town service tiles).

Your answer: ___

---

2. Basic vs block text (OP_01 / OP_02 / OP_03)

Scenario: Nordon/Nordonna intro dialogue vs a one-line “Travel (y/n)?” prompt vs a multi-paragraph NPC speech box.

• A. OP_01 = single-line / simple prompts; OP_02 = multi-line scroll block; OP_03 = same block as OP_02 after extra window prep.
• B. Nordon intro uses OP_01; all y/n gates use OP_02.
• C. All three look identical on screen — opcode choice is arbitrary.
• D. OP_03 is the only opcode that can show more than one paragraph.

RE guess: A — loc 60 Nordon strings are referenced as blocks; town y/n tiles commonly decompile to OP_01 + prompt_yes_no.

Your answer: ___

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3. Engine thunks (OP_0D)

Scenario: A tile runs script bytes but never opens a shop window (OP_0E).

• A. Never — OP_0D is always followed by visible text you remember.
• B. Yes — e.g. cruise/arena return: engine_call(0x09) then map_transition, with no shop selector.
• C. Yes — chest/treasure UI opens directly from OP_0D alone.
• D. OP_0D only appears in overlay banks 60–70, not walkable maps.

RE guess: B — multiple overworld scripts call engine_call(0x09) paired with map_transition (e.g. cruise ride loc 14, Corak's Cave door loc 22); per-index table still Unknown.

Your answer: ___

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4. Service title window position (OP_0B arg2)

Scenario: Same inn/blacksmith tile, different party facing or roster size.

• A. Title box always appears in the same screen slot; arg2 is a mode/id, not facing math.
• B. Box shifts vertically based on party facing (like OP_05 popups).
• C. Box shifts when you have more than four live members.
• D. You have never noticed the service title box at all — only the shop UI.

RE guess: A — arg2 is passed to -$7FBC as a mode byte; no facing hook traced in the OP_0B handler (Partial).

Your answer: ___

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5. Unknown OP_0E selectors (default range bins)

Scenario: Arena entrance, Monster Bowl, guild enrollment beyond mage guild (0x0D).

• A. Arena combat is not OP_0E — entirely separate combat trigger; selectors 0x09–0x10 are misc shops only.
• B. Town arena tiles call unnamed selectors (e.g. Middlegate 0x10, Sandsobar 0x49) that enter combat/ticket flow inside the engine thunk.
• C. Every selector 0x09–0xFB opens the same generic shop UI with different inventory tables only.
• D. Arena entry uses selector 0x64 (portal travel).

RE guess: B — arena entrance tiles decompile to exec_selector(0x10) / 0x49 / etc., not OP_12 in the visible script (Partial).

Your answer: ___

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6. Special OP_0E selectors (0x64, 0xC9–0xCF, 0xE2, 0xFD)

Scenario: Mystic portal, quest milestones, endgame.

• A. 0x64 = long-distance portal travel; 0xC9–0xCF = quest-specific handlers; 0xFD = late-game / unused in normal play.
• B. All of these are just renamed blacksmith shops.
• C. 0xE2 = arena only; 0x64 = boat ferry.
• D. You fire 0xFD regularly in early game.

RE guess: A — names in SELECTOR_NAMES + portal tiles using high selectors; 0xFD seen rarely (Partial).

Your answer: ___

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7. Encounter tail bytes (OP_12 / OP_13)

Scenario: Same monster IDs, different fight feel (arena backdrop, boss tone, no escape).

• A. Tail byte 1 = terrain/backdrop id; tail byte 2 = flags (escape, arena, difficulty band).
• B. Both bytes are fixed 0x00 in all real fights — purely padding.
• C. Tail bytes set party level / scaled HP only.
• D. Tail byte 1 = gold reward multiplier; byte 2 unused.

RE guess: A — scripts emit varied non-zero tails (06 02, 11 5C, 05 F0, …) with stable 10-byte monster blocks (Partial, tail table not dumped).

Your answer: ___

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8. Party byte apply (OP_15 / masked OP_18)

Scenario: Olympic Trial skill purchase, hire restrictions, quest progress bits.

• A. Sets per-member flag/field bytes (skills owned, class gates, quest bits) — not direct HP damage.
• B. Always deducts gold when OP_15 runs (same opcode as payment).
• C. Only used for alignment/reputation changes you see in a stat panel.
• D. You have never noticed any effect from these ops in play.

RE guess: A — Atlantium Olympic Trial uses apply_party / apply_party_masked on field 0x6D before party_effect skill grant (Partial).

Your answer: ___

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9. Party effects (OP_1F / OP_20)

Scenario: Fountain heals, temple cure, trainer spell/skill grant, stat shrine.

• A. Selector byte chooses effect class (heal, cure, teach skill/spell, buff); OP_20 is a variant mode of the same dispatcher.
• B. Only restores HP — poison/cure uses a different opcode family entirely.
• C. Purely cosmetic — no stat or HP change.
• D. Always grants a random item.

RE guess: A — party_effect(sel=0x09, …) follows skill prompts; party_effect(sel=0x80, …) follows shrine/fountain chains (Partial).

Your answer: ___

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10. Map tile mutation (OP_21)

Scenario: Barrier drops, door opens, wall becomes floor — still there after leaving the tile.

• A. Yes — e.g. Corak's Cave barriers lowered with visible map change (set_tile on adjacent cells).
• B. Only clears the event bit (OP_14); graphics never change.
• C. Visual change is session-only — resets on town exit.
• D. You recall permanent changes but they were cut-scene transitions, not tile writes.

RE guess: A — loc 22 Hero's Tomb script writes collision/visual bytes via OP_21 then OP_14 (Partial).

Your answer: ___

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11. Non-gold predicate codes (OP_25 values 0, 1, 2)

Scenario: Our decoder labels flag_clear / flag_set / flag_alt.

• A. Generic script/state flags (quest done, already paid, etc.) — not item IDs.
• B. Directly encode ticket colors (0=green … 2=black).
• C. Bishop freed / arena won / goblet returned map 1:1 to codes 0/1/2.
• D. You have never hit a gate you would attribute to OP_25 — likely wrong decode.

RE guess: A — --predicates finds zero recoverable OP_25 hits in event.dat; small integer codes fit flag words, not items (Partial, high uncertainty).

Your answer: ___

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12. Tickets/keys: check vs consume (OP_25 vs OP_28)

Scenario: Arena ticket turn-in vs bishop cage key.

• A. Tickets: OP_25 check then separate OP_28 consume in the same script step.
• B. Tickets: handled inside OP_0E arena selectors (engine inventory logic); keys: explicit OP_28 in castle scripts.
• C. Both tickets and keys use only OP_25; OP_28 is for quest discs/rings.
• D. Keys check without consume — you keep the key after freeing a bishop.

RE guess: B — OP_28 consume hits map to keys/discs/rings; no ticket item IDs (208–211) appear in OP_28 contexts; arena tiles call exec_selector instead (Partial).

Your answer: ___

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13. Gold predicate (OP_24)

Scenario: “Travel for 25 gold (y/n)?” — you accept and have enough gold.

• A. OP_24 is check only (gold ≥ amount); a later op/engine call deducts if you proceed.
• B. OP_24 both checks and subtracts gold immediately when true.
• C. OP_24 checks individual member gold, not party total.
• D. Failed check still deducts partial gold.

RE guess: A — scripts pair check_gold_at_least(N) with if not cond: skip then map_transition / party_effect; no subtract in the OP_24 handler (Partial).

Your answer: ___

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14. Combat-gated token skip (OP_2B)

Scenario: When does the skip walk actually run? (A4-$77BD must be set.)

• A. Primarily after combat victory / arena return cleanup (flag set @ 0x12438 and related combat paths).
• B. Any time you skip a dialog with ESC.
• C. Whenever a y/n prompt appears.
• D. You have noticed OP_2B branches firing outside combat — e.g. shops, travel.

RE guess: A — $77BD is set on victory (combat_victory_rewards) and cleared on many map/event exits; OP_2B no-ops when clear (Partial).

Your answer: ___

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15. Calendar / day gate (OP_23)

Scenario: NPCs or tiles that only work on certain days or moon phases.

• A. Yes — obvious day-locked quests you can name (matches OP_23 / day-of-year table).
• B. Only subtle — benefits “once per moon phase” feel calendar-driven but may use vars, not OP_23.
• C. Era gates (OP_22) cover all time travel; OP_23 never matters in normal play.
• D. Unsure — never noticed any day-specific behavior.

RE guess: B — moon-phase shrine text uses load_var8 + store_var8, not OP_23; OP_23 reads -$79DE[era] (Partial).

Your answer: ___

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16. Location 60 — Nordon intro bank

Scenario: Corak prologue / Nordon / Nordonna dialogue.

• A. Shown only during the opening castle/tutorial sequence — not re-triggerable from a town tile later.
• B. Re-accessible anytime by returning to Middlegate castle tiles.
• C. Random encounter text anywhere in the world.
• D. Visible only in the Hall of Spells UI.

RE guess: A — loc 60 is a string_bank; most event segments are missing/trigger-only placeholders, not normal map scripts (Partial).

Your answer: ___

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17. Location 61 — spell / hireling tables

Scenario: % / letter garbage vs normal prose.

• A. Never seen in gameplay — metadata for shop/HoS/hire UI only.
• B. Shows as garbled text if you walk the wrong tile in a town.
• C. Appears during spell purchase windows as formatting codes.
• D. Same strings as location 70, duplicated for testing.

RE guess: A — loc 61 decodes as encoded tables; no readable quest prose in the string list (Partial).

Your answer: ___

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18. Location 67 — Hall of Spells mixed pool

Scenario: Spell purchase / class check scripts vs dead data.

• A. Dead — superseded entirely by loc 70 strings.
• B. Still executed via queued dispatch (0x176B6) for HoS/class flows; contains opcodes outside 0x00–0x32.
• C. Only runs during endgame (OP_22 era gate).
• D. You have bought spells from a tile whose script clearly lives in loc 67.

RE guess: B — loc 67 has runnable segments (prompt_yes_no + map_transition) plus non-standard opcodes; overlay path differs from tile scanner (Partial).

Your answer: ___

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19. Location 70 — meta bank (bishops, puzzles, HoS)

Scenario: Bishop cage text, “Yellow Interleave” puzzle, Triple Crown hints.

• A. Pulled during castle/bishop events; all four bishops use the same key-check/consume pattern (color-matched key).
• B. Bishops use tickets; keys are Sandsobar-only.
• C. Puzzle text is shown as a normal OP_06 sign in Pinehurst overworld only.
• D. Loc 70 is never read at runtime — editor artifact.

RE guess: A — loc 70 strings include Green Bishop + Yellow Interleave; castle overlays consume Yellow/Red/Black keys via OP_28 matching bishop color (Partial).

Your answer: ___

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20. Castle blobs (locations 63 / 65 / 68)

Scenario: Runtime behavior vs opaque static data.

• A. Normal tile events fire from these records today (bishop cages, sieges).
• B. Partial — engine reads blob bytes directly; not via standard triplet scanner (00 00 00 missing).
• C. Completely unused on Amiga retail — dead padding.
• D. Only used if you hack event.dat — vanilla never touches them.

RE guess: B — flagged castle_blob in inventory; queued dispatch likely consumes bytes without normal init (Partial).

Your answer: ___

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21. Olympic Trial (Atlantium, event @ “Hurl the spear…”)

Scenario: Text-only today — ever combat later?

• A. Permanently non-combat — pays 500 gp to teach Athlete skill via apply_party / party_effect.
• B. Starts combat if you refuse the y/n prompt.
• C. Becomes a combat arena after a quest flag or era change.
• D. Was combat in an earlier retail build — patch changed it.

RE guess: A — loc 01 event 27 decompiles to skill purchase, not encounter_setup; user already reported text-only (Partial).

Your answer: ___

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22. Arena ticket color per town

Scenario: Which colored ticket item gates each town arena? (items.dat: Green 208, Yellow 209, Red 210, Black 211 — note typo “Yellow Tickt”.)

• A. Middlegate=Green, Atlantium=Yellow, Sandsobar=Black, Vulcania=Red.
• B. Middlegate=Yellow, Atlantium=Green, Sandsobar=Red, Vulcania=Black.
• C. All four towns accept any ticket color.
• D. Tundara sells tickets but has no arena — ignore for pairing.

RE guess: A — Vulcania=Red is user-verified; four ticket items match four arena towns; Sandsobar Triple Crown text highlights Black ticket for cross-arena quest (Partial — exact shop→color mapping not in decoded scripts).

Your answer: ___

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After you fill this in, please note any wrong RE guess lines inline — that is the highest-value feedback for the opcode gap table.

Interactive quiz: python tools/mm2_event_quiz.py (saves answers to EXTRACTED/event_quiz_answers.json).

Tooling

tools/decode_event.py now includes:

• opcode map for 0x00..0x32
• raw script preview
• marker-based disassembly pass starting at opcode 0x22 candidates