Turn order, double attacks and kicks

The Spikefish Flute cancels enemy turns (the Koru flute glitch)

Reported as

In a boss fight the flute skips the party's remaining turns, and for every party member who already acted it also cancels an enemy turn, slowest enemy first. Against Koru it can stop Dead End Crisis for good (community report).

Cause

The flute's turn-skip adds one to the round's turn count per living party member instead of per member still waiting, so the round ends early

Where

Spikefish cast module, PROT entry 0925, tail at 0x801F79B8; round-over test in the battle overlay, PROT entry 0898, at 0x801E67C8

Affects

Every fight flagged as scripted (boss fights), on the USA, Japanese and French discs; only Koru's script can be pushed off its end

Status

Explained - from the code and disc data; the early round end and a boss's thrown-away decision were captured on a poked state in the evolved Cort fight; Koru's own fight was not run

A battle round is a count, not a list of turns. One byte counts how many turns have been taken this round, and the round ends when that count reaches the number of fighters. Who goes next is decided fresh after every action: the fighter holding the highest unspent initiative key.

The flute is an escape item. In a fight flagged as scripted it cannot flee, so only the tail of its code runs, and that tail is meant to throw away the party's remaining turns. It does it by adding one to the turn count for every living party member, subtracting one, and zeroing the party's keys. With p party members already done, the count runs p too far and the round ends p turns early. Only monsters still hold keys, and the highest key always goes first, so the turns that fall off the end belong to the slowest enemies.

So a flute used as the round's first action skips nobody: the rest of the party loses its turns and every enemy still acts. The boss's place in the order does not matter, only how many party members went before the flute. A boss that has already acted has nothing left to lose.

Why Koru never recovers

Koru has no timer. His script picks a move from the battle's round number, and only round number 4 means Dead End Crisis. The round number rises at every round end whoever acted. End that round before he moves and the number is 5, which his script has no entry for; it does not come back to 4 until the byte wraps. The on-screen countdown is 4 - round number stored in one byte, which is why it reads 255. Nothing writes 255 anywhere.

With nothing scripted, the generic monster picker is all that is left. Koru's record carries no usable spell, so it builds a plain attack from his two costed attack animations. Both list their hit at frame 200, on clips only 64 and 30 frames long, so the hit never fires: the animation plays and nothing lands. His real specials take their damage and effect sprites from his own cast module, which a plain attack never runs.

In an ordinary, non-scripted fight the same item ends the battle: the party walks off and the escape teardown runs.

The boss still decides on a turn it never gets

1. Flute endsparty keys are zero, the count is already too high
2. Pickthe boss holds the highest key, so it is picked and its script chooses a move · 0x801E5D58, 0x801DAF48
3. Round-over testthe count has reached the end; the chosen move is discarded · 0x801E67C8
4. Next roundround number +1, every key rolled again · 0x801E6810, 0x801DA780

For Koru this changes nothing, because his script keeps no memory. For a boss whose script writes something down at the moment it chooses, that note still changes on the discarded turn. Evolved Cort is the clear case: the game records "Ultra Charge was used" when he decides, not when the move plays, and clears it when he decides on Final Crisis. A thrown-away decision can therefore wipe out a charged Final Crisis, or make him fire one next turn without ever visibly charging.

Keys are rolled fresh every round (speed plus a random amount up to half of it), so a fast party's flute user sometimes rolls first, and then the flute skips nobody. That is the "sometimes" in reports about other bosses.

What each boss loses

Each row is read from that boss's own script in the battle overlay.

The flag applies to every fight launched from a formation row whose first byte is non-zero: the two Piura, Caruban and Golem in Rikuroa, the Viguro pair, Zeto, all three Songi, all three Berserkers, Van Saryu, Dohati, Xain, the Kemaro pair, the Puera fights and Zora in the Floating Castle, late Tetsu, both Gaza, Lu / Che / Gi, Koru, Rogue, Jette, Caruban $2 / $3 and both Cort forms. Lapis, the opening Tetsu, Queen Bee and Gold Face are not flagged, so there the flute simply flees.

Watched in the evolved Cort fight

Captured on a poked state. The run starts from a save state of the real evolved Cort fight as reached in play (Vahn, Noa and Gala; the scripted-fight byte reads 4), on the retail disc; that state has an unrelated place-name patch resident in memory. Written by hand: party HP held at 9000; party speed, so that the order is seat 0, seat 1, Cort, seat 2; the queued actions of seats 1 and 2, changed to the Spikefish cast; and, on the opening round only, one random draw in Cort's script so that he takes Ultra Charge. His Final Crisis pick on the next round was not forced.

Three more runs of the same fight show the other case: with the flute user as the first party member to act, the cursor goes to 3 of 4, the other two party turns are dropped and Cort takes his turn.

Not watched: Koru's own fight (the 255 countdown and the attacks that never land rest on the code and his monster record), the Ultra Charge direction of the thrown-away decision, and Van Saryu's one-time Jugger Power.

The Japanese and French discs

The trick is not particular to the USA disc. The Japanese build (SCPS_100.59) is a different compile with its overlays loaded higher and some context fields at other offsets, and every link of the chain is there with the same logic. Koru's monster data is byte-identical from the end of his name onward. The French build (SCES_019.44) is the USA code relocated: its flute tail (0x801F83E0) and round-over step (0x801E70EC) match instruction for instruction. Neither regional disc was run; this is from their code.

801f73e8  lbu  v0,0x287(a0)        ; scripted-fight byte
801f73f0  bne  v0,zero,0x801f79b8  ; scripted: skip the escape
801f79e0  lhu  v0,0x14c(v0)        ; seat HP
801f79f0  lbu  v0,0x9(s4)
801f79fc  sb   v0,0x9(s4)          ; cursor += 1 per LIVING party seat
801f7a2c  jal  0x800421d4          ; refund an unspent Item turn
801f7a60  sb   v0,0x9(s4)          ; cursor -= 1
801f7a70  sh   zero,0x16c(v1)      ; party keys = 0 (also 7a7c, 7a88)

801e67a4  addiu v0,v0,1            ; cursor += 1
801e67b4  lbu  v1,0(a2)            ; party count
801e67b8  lbu  a0,1(a2)            ; monster count
801e67bc  lbu  a1,0x14(s5)         ; ctx+0x25, dropped without acting
801e67c8  slt  v0,v0,v1            ; cursor < party + monsters - dropped ?

801eb538  lbu   v1,0x28a(v0)       ; round counter
801eb540  sltiu v0,v1,5
801eb544  beqz  v0,0x801ebdac      ; 5 or more: nothing scripted

801eba74  lw    v0,4(s0)           ; 0x801C8FE4, the charge flag
801eba7c  bnez  v0,0x801ebae8      ; charged: the Final Crisis arm
801eba8c  andi  v0,v0,3            ; else a 1-in-4 roll, needs 200 MP
801ebab8  sb    v0,0x1df(s4)       ; queue 0xA5 Ultra Charge
801ebad4  sw    v0,4(s0)           ; flag += 1
801ebaec  li    v0,0xb4            ; queue Final Crisis
801ebb14  sw    v0,4(v1)           ; flag -= 1

Addresses

Verifying it

The Koru half is the part still to be run. Break on 0x801F79F0 and 0x801E67C8. Watch the byte at ctx+0x1A, the byte at ctx+0x28A, the byte at 0x801F6958, and the halfword +0x16C of all four fighters. With the flute used second or third on the round where the counter reads 4, the three party keys drop to zero together, the cursor jumps by (living party - 1), and the counter goes 4 to 5 while Koru's key is still non-zero. Repeat with the flute used first: Koru acts.

For a thrown-away decision, add a write watch on 0x801C8FE4 and a breakpoint on the action dispatch at 0x801E2CDC: the word changes in state 0x50 and no dispatch for the boss follows before the round counter moves.

Open: whether a member who is alive but cannot act (petrified or captured) shifts the overshoot by one, since the flute's loop tests HP only; the two uncaptured rows above (evolved Cort's Ultra Charge direction, Van Saryu); and which of the flagged Rikuroa rows belongs to which of Caruban, the Golem and the Piura.

The War God Icon sometimes gives only one attack string

Reported as

The accessory should make the wearer attack twice in a row, but it randomly fails to; players describe it in solo Muscle Dome Master Course fights (community report).

Cause

The "second pass used" byte doubles as the Low command's AP cost, so typing commands sets it; only an attacker stepping up to a target clears it

Where

Battle action state machine FUN_801E295C and the arts gauge build FUN_801D388C, PROT entry 0898; byte at ctx+0x16

Affects

Every wearer, plain attacks, Arts and counterattacks; in practice one-on-one fights with hand-typed commands

Status

Explained - read from the code, and the refusal captured on a poked state (the wearer was nudged into reach); a refusal with nothing nudged, and how often Noa or Gala hit it, are not measured

There is no dice roll. At the end of the first attack string the game grants the replay only if a one-byte pass counter reads zero.

That byte is shared with something unrelated: the AP cost of the Low command on the arts-entry screen. Every time a fighter's command gauge is built for typing commands by hand, the byte is set to that cost, 30. A doubled attack also leaves it at 2 or more. The game clears it in exactly one place: at the end of the short "step up to the target" phase of an attack.

So the marker reads "second pass already used" at the start of every round whose commands were typed, and stays that way until some attacker, party or monster, has to close the distance to a target. If the wearer swings before anyone has done that and is already within reach, the step-up phase is skipped, nothing has cleared the byte, and the replay is refused. The single pass that does run deals its damage normally.

Fighters are not walked back after an action. A monster that has just hit the wearer is left standing at the very edge of the wearer's reach, and which side of the edge depends on the knock-back of the move it used and on who the wearer is: Vahn's reach is 43 units shorter than Noa's and 96 shorter than Gala's. The failing round is: the wearer is the first to attack, types commands by hand, and targets the monster that hit them last round while it is still within reach. In a crowded fight the other attackers shove the target away and clear the byte, so it almost never lines up. In a one-on-one fight, which is where players report it, it can.

Avoiding it: choose Auto instead of typing commands, attack a different monster, or let anyone else attack first.

Being in reach is not enough on its own: a wearer who starts in reach with a clean byte still doubles. A counterattack by the wearer is decided the same way, since the counterer takes over inside the strike loop and inherits whatever the byte holds. Nothing else cuts the second string: the target cannot die between the passes (the first pass's damage is held back until the second ends), there is no AP check, and monsters never counter.

Watched in play

Two fights were run on the retail disc: three-on-one against Gaza and one-on-one against a Gobu Gobu. No available save has the Icon equipped, so in every run the ability bit was written onto Vahn by hand (bit 0x2000 set in the word at 0x800847FC). The Gaza state has an unrelated arts-AP patch resident in the battle overlay; the Gobu Gobu state is retail apart from four data bytes.

How close an unassisted wearer gets. With his position left alone, Vahn attacking the Gobu Gobu that had just hit him was 0 to 49 units outside reach in eleven rounds and inside it in one. In ten of those eleven the margin is smaller than his own 43-unit handicap, so Noa or Gala standing in the same spot would have been in reach; that is an inference from Vahn's numbers, not a capture with them wearing the Icon. Against Gaza with three attackers, every start was far out of reach.

801e39bc  sltiu v0,v0,3            ; party seat
801e39fc  lw    v0,0x6bc(v0)       ; character record +0xF4
801e3a04  andi  v0,v0,0x2000       ; War God Icon bit
801e3a10  lbu   v0,5(s5)           ; pass counter
801e3a18  bnez  v0,0x801e3a74      ; NON-ZERO: no second pass
801e3a38  sb    zero,4(s5)         ; rewind the strike cursor
801e3a40  sb    v0,5(s5)           ; counter += 1

801e35b0  sb    v0,7(v1)           ; state = 0x1E
801e35b4  sb    zero,5(s5)         ; pass counter = 0

801e31f4  jal   0x8004e2f0         ; range check
801e3200  bnez  v0,0x801e3230      ; out of reach: approach
801e3210  sb    v0,7(v1)           ; in reach: state = 0x1E, counter untouched

801d3b3c  sb    v0,3(a2)           ; a2 = s4 + i, i = 0..3: ctx+0x14+i
801d3bc8  sltiu v0,a3,4            ; Left, High, Low, Right

Addresses

Verifying it

Watch the byte at ctx+0x16. Break on 0x801E3A18: a non-zero read there is a refused second pass. Break on 0x801E320C with ctx+0x13 < 3 to catch the in-reach bypass, and on 0x801E31FC to log the range result. Writing zero to the byte at 0x801E3A10 restores the double.

The run that would close the remaining gap: a memory-card save with the Icon on Noa or Gala in a one-on-one Muscle Dome fight, commands typed by hand, the wearer faster than the opponent, logging the range result and the string-end read over ten rounds. The prediction is "in reach" and a non-zero read on most rounds that follow the opponent's attack.

Open: a refusal with nothing nudged; how often a Noa or Gala wearer starts in reach; the wearer's own counterattack and the one-byte wrap are read from the code, not captured.

Side Kick's first hit misses floating enemies even with War God Boots

Reported as

War God Boots let Gala's low kick hit floating enemies, but Side Kick still misses its first hit against them (community report).

Cause

Reach is a property of each hit's power byte. The boots swap in a different low-kick record; Side Kick is an art with its own fixed bytes

Where

Melee kernel FUN_801EC3E4, PROT entry 0898, test at 0x801EC488; bytes in Gala's battle file, PROT entry 0865

Affects

One art hit in the whole game; the floating monsters listed below

Status

Explained - from the code and disc data, no capture

Whether a hit can reach a floating enemy is decided by the hit's own power byte, not by anything on the attacker. Low hits come in two encodings: one that cannot reach a floater and one that always connects.

The boots grant no ability. Every pair of shoes ships its own Low and High kick, and the War God Boots' Low kick simply carries the always-connects byte where Gala's other shoes carry the restricted one.

Side Kick is not a shoe's kick. It is an art, stored in Gala's art bank with the fixed power run 12 17. The first byte is the restricted kind, so the first hit misses a floater; the second connects. Changing boots never touches an art record. Across all three characters' art banks it is the only hit encoded this way.

801ec488  sltiu v0,a3,3            ; party attacker only
801ec494  lbu   a0,0(a1)           ; this hit's power byte
801ec49c  sltiu a1,a0,0x16         ; 0x16 and up always connects
801ec4c0  lbu   v1,0x1e(v0)        ; target monster record +0x1E
801ec4cc  sltiu v0,a0,0x11         ; class 2: bytes 0x11..0x15 miss
801ec53c  sltiu v0,v0,0x11         ; class 3: bytes below 0x11 miss
801ec554  sb    v0,0x263(v1)       ; miss flag, no roll, no damage

Who and what it applies to

Floating monsters (height class 2): Evil Fly, Death Wings, Demon Fly, Drake Ghost, Guardian, Ghost Knight, the Theeder, Vera, Nighto, Viguro, Gola Gola, Slippery, Puera and Gilium families, Pump Bat, Devil Pump, Boogie Pump, Hornet, Killer Bee, Queen Bee, Spikefish, Mad Bird, Wailing Bird, Mage, Sorcerer, Thermo, Amethyst, Garnet, Topaz, the Evil Bat records, Lapis, Rogue and Zora.

Short monsters (class 3, missed by restricted High kicks): Mushroom, Mushrin, Mush Mush, Frog, Gel Frog, King Frog.

Addresses

Verifying it

Fight an Evil Fly with Gala in War God Boots and break on 0x801EC494. A plain Low reads 0x1D and connects. Side Kick reads 0x12 on its first hit, branches to 0x801EC548 and sets the miss flag; its second reads 0x17 and connects. Changing the art record's first power byte from 0x12 to 0x1C (same multiplier, free range) makes the first hit land.

Open: whether 0x12 is a deliberate low sweep or an authoring slip cannot be told from the data.

The level-3 dance special swallows the next special

Reported as

In the dance minigame, the level-3 special animation "eats" the next special if two level-3 specials are done in a row (community report). The special is the Triangle move, the lesson's "groovy move". An early fan guide gives the same warning: used at level 3, it lasts so long that you miss the next move.

Cause

Presses are only judged while the idle or dance loop plays; the level-3 Triangle move runs 6.83 beats, past the next scoring slot and the next combo's first note

Where

Dance overlay, PROT entry 0980: per-dancer tick FUN_801D1358, gate at 0x801D168C

Affects

Every dancer and every triggered move; worst at level 3

Status

Explained - read from code and data, and captured in the running game with scripted button presses and nothing written to memory

A dancer's button presses are judged only while its body is playing the idle or the basic dance loop. Every triggered move, whether a combo finisher, the Triangle "groovy move" or the flinch after a wrong press, is a one-shot animation, and until it reaches its last frame the judge is not called at all. A press made during it is not stored, not counted as a miss, and for Triangle does not use up one of the three per song. It vanishes.

The level-3 animations are the longest. The level-3 Triangle move lasts 6.83 beats. The next scoring slot closes at most 4.75 beats after the press, so a second Triangle there is always lost. The next level-3 combo starts 6 beats after the press, so its first note is lost too and that combo cannot be completed. A Triangle on the last note of that combo, 8 beats on, does register.

Holding the button does not help: the game only sees a button on the frame it goes down.

Triangle pays its real reward only on a combo slot (every fourth beat) inside the timing window. A press made up to 0.75 beat into one slot can be followed on the next slot no later than 4.75 beats afterwards:

The level-3 chart places one three-note combo per eight beats, so two combo finishers in a row never collide. A Triangle dropped inside the lock does not reduce the stock. A Triangle pressed after the lock ends but outside a combo-slot window does spend one, for only a few points, which is the other way a second special can feel swallowed. Triangle pressed together with Square or Circle is judged as Triangle alone, so "with the last command of a combination" means "instead of it".

The code also has a per-dancer "queued move" flag that would start a follow-up move when the current one ends. The move number is written on every completed combo, but the flag itself is only ever written zero: nothing else on the disc that can be loaded with the dance hall refers to it, and a write watch during the runs saw only the two zero stores. The follow-up never fires. It reads as an unfinished "chain the next move" path, which is an inference.

Watched in play

The qualifier (Noa and two rivals) was run in the retail dance hall. Every input went through the emulator's controller; level 3 was reached by pressing the chart's own notes; nothing was written to memory. The run starts from a save state taken on the way into the hall, which then loads the dance code from the retail disc. That state has an unrelated patch resident in the main executable: four code sites differ from the disc, none in the frame-timing or animation code, and the dance overlay's code is byte-identical to the disc's.

Triangle on consecutive combo slots at level 3:

The gate stayed shut for exactly 64 game frames after each judged level-3 Triangle. Other runs: from the start of a song, the level-1 Triangle reopens the gate after 24 frames and the next press is judged, the level-2 Triangle holds it for 46 and the press on the next slot is neither judged nor spent. With the next combo played normally after a level-3 Triangle, its first note is not judged, the other two score as plain hits and the combo does not close. With Triangle pressed on that combo's last note instead, it is judged and pays in full. A dropped Triangle held down for 80 frames, through the end of the lock, shows in the pad word on one frame only and never fires.

801d168c  lw   v0,0x10(s1)         ; idle clip id
801d1690  lh   v1,0x5c(s0)         ; clip bound right now
801d1698  beq  v1,v0,0x801d16b4    ; idle: judge
801d16a0  lw   v0,0x18(s1)         ; dance-loop clip id
801d16ac  bne  v1,v0,0x801d1750    ; anything else: skip the judge
801d16b4  jal  0x801d1af4          ; judge / award routine

Addresses

Verifying it

Break on 0x801D16B4 for dancer 0 and log the frame number. After a level-3 Triangle the next hit comes 64 game frames later at the hall's frame delta of 3. Or watch the bound clip id at actor +0x5C: presses made while it reads 0x11 show in the pad word at 0x8007B874 but never reach 0x801D1AF4, and the stock word at 0x801D534C does not change.

The capture ran the qualifier only; the gate is the same code in every mode of the minigame.

See also

Battle action state machine · damage formulas · art data · player battle files · accessory passives · the arts command gauge · the endless camera orbit