Crystal/docs/NATIVE_PORT.md

Native port status and reference checks

Reproducible reference

The private .reference/pokecrystal checkout is pinned to 7a7881d0d62e0ddbd82dcf10e7116807487ac651. With RGBDS 1.0.3, its crystal11 build is byte-identical to the supplied English US/Europe revision 1.1 ROM. npm run check:reference verifies the files and commit. It checks every ROM and RAM address in src/game/rom/profile.ts against generated symbols, event constants against constants/event_flags.asm, and map-group bounds against data/maps/maps.asm.

To recreate the private reference:

git clone https://github.com/pret/pokecrystal.git .reference/pokecrystal
git -C .reference/pokecrystal checkout 7a7881d0d62e0ddbd82dcf10e7116807487ac651
make -C .reference/pokecrystal crystal11 -j4
npm run check:reference

Install RGBDS 1.0.3 separately. No script downloads a game ROM. CRYSTAL_ROM_PATH optionally selects another local location; checks otherwise use Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc at the root.

The reference checkout, rebuilt ROM, extracted graphics, saves and gameplay screenshots must stay local and ignored. The shipping profile contains addresses and format constants, not game content.

Routine map

These paths refer to the pinned PRET source.

Native module	PRET reference	Evidence and limits
game/rom/lz.ts	home/decompress.asm	All LZ command types have unit vectors; six tilesets match original ASM execution byte-for-byte.
game/rom/assets.ts maps/events	data/maps/maps.asm, data/maps/attributes.asm, data/maps/scenes.asm, data/maps/landmarks.asm, macros/scripts/maps.asm	Any map header in the ROM's 26 groups decodes; only maps explicitly listed in NATIVE_MAPS can be entered. Location names, scene-variable owners and connection offsets come from the ROM.
Tiles/palettes	home/map.asm, engine/gfx/color.asm, engine/tilesets/mapgroup_roofs.asm	Graphics match rebuilt reference bytes. Connected maps draw beyond the edges with the current tileset, like the original strips. Terrain animation and other special palettes pending.
Sprites/rendering	data/sprites/sprites.asm, data/sprites/facings.asm, data/sprites/emotes.asm	Chris/Kris, standard NPCs, emote bubbles and jump shadows decoded. Walking frames follow SetFacingStepAction. Dynamic Pokémon icons and room decorations pending.
game/world/world.ts	engine/overworld/events.asm, player_movement.asm, warp_connection.asm, data/collision/collision_permissions.asm	30 Hz overworld ticks, 8-tick walks, 16-tick ledge jumps, directional mats, animated door/stair exits, connection coordinates, events, scenes and callbacks. NPC random walks and spins follow HandleNPCStep. Surfing remains absent; turn timing still needs comparison.
Event interpreter	macros/scripts/events.asm, engine/overworld/scripting.asm, engine/events/std_scripts.asm	Resumable; yields text, choices, movement, emotes and pauses. Scenes, phone contacts, string buffers and object commands. Unknown commands and specials abort without committing.
Movement interpreter	macros/scripts/movement.asm, engine/overworld/movement.asm, engine/overworld/map_objects.asm	Turns, steps, slides, jumps (two tiles with the original arc), sleeps, facing locks, visibility and emotes. follow moves the follower into the leader's previous square.
Specials	data/events/special_pointers.asm, engine/rtc/timeset.asm, engine/overworld/decorations.asm	Selected by routine address from the ROM table: SetDayOfWeek, initial DST flags, RestartMapMusic (no audio yet), the empty-room decoration toggles, HealParty, HealMachineAnim (presentation only), CheckPokerus and the StubbedTrainerRankings_Healings stub.
game/rom/pokemon.ts	data/pokemon/base_stats, evos_attacks.asm, data/moves/moves.asm, data/items/attributes.asm, engine/gfx/load_pics.asm	Species, move and item names, base data, learnsets, move PP, item pockets, growth-rate exp and front pictures (FixPicBank, PadFrontpic). Starter pictures match rebuilt bytes.
game/party	engine/pokemon/move_mon.asm, engine/pokemon/caught_data.asm, engine/items/items.asm	GeneratePartyMonStats for script gifts: DVs, FillMoves, PP, exp, CalcMonStatC, happiness and caught data. PutItemInPocket, key items and TossItem. PC boxes, TMs and HMs are refused.
Text interpreter	macros/scripts/text.asm, constants/charmap.asm, home/text.asm	Literal/far text, RAM names and string buffers from native state, numbers of dots, and sound or pause cues (consumed). text_asm and other RAM reads are refused.

Supported event opcodes are explicit in the interpreter switch. Audio commands consume their operands, but sound sequencing is pending; those opcodes do not imply complete audiovisual behavior. pause holds the current text or waits the original number of overworld ticks.

Scripts run on a private draft. The world presents each yielded effect, then resumes the script with the player's answer or when the animation ends. The draft is committed only when the script ends. A save made during a scene returns the committed state, and coordinate events rewind to the source of the triggering walk or two-tile jump. Saves during movement also retain the source tile until arrival events run, including across map connections. A failed scene restores the positions it had changed. As in LoadMapObjects, map objects spawn when the map loads. Later flag changes do not remove objects already shown; only appear and disappear do.

The opening scenes currently run end to end from the ROM: Mom's Pokégear, weekday and DST scene, the teacher at the west edge, the rival at the lab window, Elm's introduction with its yes/no loop, the lab's exit guard, the starter choice with pokepic, givepoke and the nickname prompt, Elm's directions and the aide's Potion through the ROM's own GiveItemScript. callasm accepts only explicitly empty routines or native translations: HalveMoney, GetWhiteoutSpawn, the item ball's TryReceiveItem and the fruit tree routines. The naming screen is a native text field limited to the characters the original offers.

Actual emulator comparison

tests/reference-parity.spec.ts loads the user's ROM into the reference emulator and places a small original test trampoline in emulated WRAM. It calls the ROM's FarDecompress routine at $0b40, then sets a return sentinel. Every output byte is compared with the native decoder for six supported map tilesets. This executes the original routine rather than comparing two copies of our code.

The same suite compares 400 damage cases and 400 type-effectiveness cases per browser against the original battle routines. Battle unit tests cover win, escape, loss, experience, level-up and move-learning flows. This establishes parity only for the compared routines and inputs. It does not prove complete gameplay, rendering, battles, audio, timing or physical-device parity. Extend controlled comparisons as each subsystem is translated.

Validation

npm test
npm run test:e2e
npm run check:reference
npm run check:vendor
npm run build
npm run check:release
npm run build:reference

User-ROM tests skip when the file is absent, including public CI. Synthetic tests still run. Comparing with rebuilt graphics also needs the private PRET build. Do not report skipped private checks as CI passes.

Native production is dist/; the optional reference output is dist-reference/. Release checks reject emulator dependencies, binary game files and embedded binary assets in the native output. Source review is still required when adding assets or data.

Save schema

Native saves are version 3. Version 2 added scene values by owning map, phone contacts, the weekday offset and DST flag, and positions of objects that scripts moved on the current map. Version 3 adds the player ID, party, bag, Pokédex seen/caught sets and money. Early version-3 backups without money receive the original starting balance; explicitly invalid balances are rejected. Restores recompute each Pokémon's stats from its DVs and reject any mismatch, and check every item against its ROM pocket. Older saves migrate with new-game defaults; a missing player ID is drawn as a new game draws it. Objects are restored from the save on continue, and only the TILES callback runs, as in MapSetupScript_Continue.

Scripted trainer battle foundation

game/rom/trainers.ts decodes TrainerGroups, TrainerClassAttributes, TrainerClassNames, TrainerClassDVs and map trainer headers. Tests cover all 542 ROM records across 67 classes; CAL2 construction refuses its SRAM-dependent Mystery Gift party.

game/battle/ai.ts translates AIChooseMove, AI_Redundant and the Basic, Setup, Types, Offensive, Opportunist, Aggressive, Cautious, Status and Risky layers. It preserves the original random tie selection, known redundancy quirks, HP thresholds, exclusions and the deterministic pre-variation damage estimate used by Aggressive and Risky. Smart remains refused, including the rival's AI. Synthetic scoring vectors establish the tested branches; original-engine AI execution parity is still pending.

loadtrainer, winlosstext and startbattle now run single-Pokémon trainer battles through the existing battle UI. Tests cover Joey's ROM party/text/reward, RUN refusal, trainer experience, Amulet Coin, CANLOSE behavior, money limits, transactional rollback and midbattle restore. Chromium and WebKit exercise the UI with a test-only script. Production map gates are unchanged. Trainer items, party switching, sight lines, trainer-object interaction and the rival round trip remain unported.

Next slice

Route 29 and Cherrygrove are enabled with item balls, fruit trees and the daily reset, the Pokémon Center nurse and the recorded whiteout spawn. NPCs roam. Next: trainer sight lines and trainer battles, capture with the catching tutorial, and party, bag and Pokégear menus over the native models. Other specials stay refused until translated.