Event to String Path

Event to String Path

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flowchart LR
  script["event.dat script"] --> op{"opcode"}
  op -- OP_01..06 --> evs["Location string bank<br/>A4-$47C8"]
  op -- OP_0B --> evs
  op -- OP_0E --> hdl["Service handler"]
  hdl --> str["str.dat A4-$703e"]
  hdl --> exe["Code hunk ASCII"]

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How event.dat dialogue reaches the player, and how OP_0E town services pull text from str.dat or the executable instead. ASM references: mm2.capstone.asm (handlers below), 07-event-script-opcodes.md, 29-embedded-exe-strings.md, 28-town-services.md.

[TOC]

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Short answer (plain language)

Mixed model. Tile scripts in event.dat only pass small numeric indices (string index, OP_0E selector byte, gold amount, etc.). They do not open str.dat directly.

• OP_01–OP_06 and OP_0B resolve text from the current location’s event.dat string bank (copied into workspace A4-$47C8, indexed via A4-$86AC / A4-$5D3C).
• OP_0E passes one selector byte into a C-like service handler (pub, inn, temple, training, guild, smith, …). That handler loads UI strings from str.dat (A4-$703e base, drawn with -$7BE4) and/or embedded ASCII in the code hunk (PEA PC-relative addresses; see doc 29).
• Numeric shop data (donation gold, spell bytes, rolled stock) comes from data-hunk master tables and/or RNG at shop-open, not from event.dat.

Pub vs inn: Food, drinks, and specialties are OP_0E 0x01 → 0x1A132 (tavern). The inn is 0x02 → -$7CD4 (rest, registry, hirelings) and uses mostly exe-embedded prompts (0x19D00…, doc 29).

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1. Interpreter entry (0x172CA)

Step	Address	Role
Tile scan	0x1754A	(y,x) triplets → event id → script PC in location record
Dispatch loop	0x1750C	Fetch opcode byte
Opcode table	0x17494	Jump table for 0x00…0x32
Invalid	0x1748C	Sets abort A4-$8616

OP_0E stub: 0x1734E → jsr 0x160C2 → return to 0x1750C.

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2. Event-local text (OP_01–OP_06, OP_0B)

2.1 Index → string bytes

Step	Address	What
Read u8 index	0x155BE	Next script byte
Resolve string	0x15884	Walk 0xFF-terminated strings in A4-$47C8; save cursor in A4-$5D44
Copy for draw	0x158C8	Copy into A4-$5D3C; @ (0x40) → newline 0x0A

Loader (0x92F2 / scanner 0x1754A) sets A4-$86AC to the location’s string base inside the decoded event work buffer. No str.dat read on this path.

2.2 Per-opcode display

Op	Handler	Text source	Draw path
01	0x15924	event.dat	-$7EC0
02	0x15942	event.dat	-$7F62 / -$7BFC / -$7C62 (multiline)
03	0x159CE	event.dat (via 02)	prep + 02
04	0x159F4	event.dat	door label -$7BE4
05	0x15A46	event.dat	large popup -$7C74 / -$7BE4
06	0x15AEE	event.dat	framed sign + border glyphs
0B	0x15DB0	event.dat (0x15756 resolves index)	service title window

OP_09 / OP_0A: y/n prompts; question text still comes from prior event opcodes, not str.dat.

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3. OP_0E selector dispatch (0x160C2)

Reads one u8 selector (0x160C0 / 0x155BE), then chained subtract / range bins (see 07-event-script-opcodes.md).

3.1 Named selectors (town services)

Sel	Decoder name	Call	Notes
0x01	open_tavern_food	0x1A132	Pub menu; A4-$79F2 town index
0x02	open_inn_lodging	-$7CD4	Inn; exe strings + gold
0x03	open_temple	0x1D208	Temple; str.dat + spell/donation tables
0x04	open_training	-$7D16	Training; HP @ 0x9BCA
0x05	open_mages_guild	-$7D10	Guild spells; membership check
0x06	open_blacksmith_shop	0x1C54A	Smith; RNG stock tables
0x07–0x08	store / special	-$7DB8 / -$7DBE	Generic shop shell
0x0A	goblet_quest	-$7DAC	Side quest
0x0D	enroll_mages_guild	-$7DA0	Sets roster $0B home town

Default path (0x15EDC → -$7DFA): selector binned to category 0x3C–0x46; temporarily overwrites A4-$79F2 with category byte for the call.

3.2 What OP_0E does not do

• Does not read event.dat strings for shop menus.
• Does not embed item names in the script; handlers use str.dat and/or rolled pointers built at shop-open.

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4. Service handlers → text sources

Global UI base: A4-$703e = loaded str.dat (see 0x7DF6, 0x807A, 0xE63C: move.l -$703e(a4), -(a7) before -$7BE4 text draw).

Handler	Selector	Primary strings	Secondary
Pub 0x1A132	0x01	str.dat menus (food A–C, drinks A–F, rumors)	Pub NPC intros in str; rumor bytecode A4-$119A uses event-style indices into rumor stream
Inn -$7CD4	0x02	Embedded exe (0x19D00…, doc 29)	Shared gold messages in str
Temple 0x1D208	0x03	str.dat priest lines + spell menu	Donation UI; spell names via spell index → str
Training -$7D16	0x04	str.dat + exe training prompts	HP path messages @ 0x9BCA
Guild -$7D10	0x05	str.dat + membership error (str ~369)	Spell list pointers A4-$6AB4
Smith 0x1C54A	0x06	str.dat + exe smith intros (0x1C51C PEA)	Category lines from A4-$5AA6; specials from RNG A4-$5A56

4.1 Pub food (0x1A132) — not the inn

• Town index: A4-$79F2 (map screen 0–4).
• Menu strings: str.dat block (~lines 109–127 in 11-str-decoded.txt).
• Food/drink effects use engine item/food helpers (-$7F68 modes 0x33, etc.); item ids come from handler tables / scripts, not from event.dat text indices.

4.2 Temple spell purchase (0x1D992 area)

• Spell indices per town: A4-$66E2 / A4-$66CE (runtime bytes).
• Display: index → spell name in str.dat (-$7E90 / -$7E8A helpers).
• Temple open (0x1D208) fills pointer tables via -$7DE2 RNG (same family as smith).

4.3 Embedded exe (doc 29)

Innkeeper dialogue, some shop chrome, training lines, chests/traps: PEA PC in code hunk 0. str.dat codec does not apply. Cross-ref category table in 29-embedded-exe-strings.md.

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5. Flow diagram

flowchart TD
  tile[Tile triplet event.dat]
  scan[Scanner 0x1754A]
  interp[Interpreter 0x172CA]
  evStr[event.dat string bank A4-47C8]
  strdat[str.dat A4-703e]
  exe[Embedded exe PEA strings]
  op01[OP_01..06 / 0B]
  op0e[OP_0E selector]
  pub[0x1A132 pub]
  inn[-7CD4 inn]
  temple[0x1D208 temple]
  smith[0x1C54A smith]

  tile --> scan --> interp
  interp --> op01 --> evStr
  interp --> op0e
  op0e --> pub --> strdat
  op0e --> inn --> exe
  op0e --> temple --> strdat
  op0e --> smith --> strdat
  smith --> exe

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6. Related tooling

Tool	Purpose
tools/decode_event.py	Opcodes + OP_0E selector names
tools/mm2_codec.py str-decode	str.dat → 11-str-decoded.txt
tools/dump_shop_tables.py	Data-hunk master numeric tables (not runtime BSS)
editor/src/core/EventOps.h	Opcode mirror

Note: tools/extract_embedded_strings.py is referenced in doc 29 but may need to be re-added to the repo; use doc 29 + capstone PEA xrefs meanwhile.

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7. Completeness (this doc)

Topic	Status
Event opcode → event.dat strings	Complete (ASM 0x15884 / 0x155BE)
OP_0E → handlers	Complete (0x160C2)
Handlers → str.dat / exe	Complete (handler survey)
Per-town numeric item/spell tables	See 28-town-services.md §13 + EXTRACTED/shop_tables.json

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See also

Page	Why
Town Services	OP_0E service handlers
event dat Format	Per-location string banks
Embedded Exe Strings	PEA PC-relative exe text
Event Script Opcodes	OP_01..OP_06, OP_0B