EVT opcode reference: all bytecode instructions

Every EVT script is a flat Bytecode array interpreted by the EVT virtual machine. Each instruction begins with an opcode constant from the EVT_OP_* enum (defined in include/evt.h), followed by an argument count and then the argument values. You never write these low-level arrays by hand — the high-level macros in include/script_api/macros.h generate them — but understanding the opcode set helps you read decompiled scripts and diagnose unexpected behavior.

EVT_OP_INTERNAL_FETCH (value 0) is used internally by the VM to prefetch the next instruction. You will never write it in a script, and the assembler macros never emit it directly.

Control flow

These opcodes govern branching, looping, and early exit from a script.

Opcode	Macro	Args	Description
`EVT_OP_END`	`End`	—	Signals the end of script data. Every script must terminate with this; a missing `End` will likely crash on load.
`EVT_OP_RETURN`	`Return`	—	Kills the current thread. A script missing `Return` will remain alive but do nothing until something else (e.g. leaving the map) kills it.
`EVT_OP_LABEL`	`Label(id)`	`id`	Marks a jump target. Valid label IDs are 0–22.
`EVT_OP_GOTO`	`Goto(id)`	`id`	Moves execution to the label with the given ID.
`EVT_OP_LOOP`	`Loop(times)`	`times`	Begins a loop. The counter is decremented after each iteration. `Loop(0)` loops infinitely. Up to 8 loops may be nested.
`EVT_OP_END_LOOP`	`EndLoop`	—	Marks the end of a loop body.
`EVT_OP_BREAK_LOOP`	`BreakLoop`	—	Exits the innermost loop immediately.
`EVT_OP_WAIT_FRAMES`	`Wait(n)`	`n`	Blocks the thread for `n` frames. This is one of the four blocking instructions.
`EVT_OP_WAIT_SECS`	`WaitSecs(n)`	`n`	Blocks the thread for `n` seconds.
`EVT_OP_IF_EQ`	`IfEq(a, b)`	`a, b`	Begins an if block that executes only when `a == b`.
`EVT_OP_IF_NE`	`IfNe(a, b)`	`a, b`	Executes when `a != b`.
`EVT_OP_IF_LT`	`IfLt(a, b)`	`a, b`	Executes when `a < b`.
`EVT_OP_IF_GT`	`IfGt(a, b)`	`a, b`	Executes when `a > b`.
`EVT_OP_IF_LE`	`IfLe(a, b)`	`a, b`	Executes when `a <= b`.
`EVT_OP_IF_GE`	`IfGe(a, b)`	`a, b`	Executes when `a >= b`.
`EVT_OP_IF_FLAG`	`IfFlag(a, b)`	`a, b`	Executes when `(a & b) != 0`.
`EVT_OP_IF_NOT_FLAG`	`IfNotFlag(a, b)`	`a, b`	Executes when `(a & b) == 0`.
`EVT_OP_ELSE`	`Else`	—	Begins the else branch of an if block.
`EVT_OP_END_IF`	`EndIf`	—	Closes an if or else block.
`EVT_OP_JUMP`	`Jump(script)`	`EvtScript*`	Jumps unconditionally to another script pointer, resetting the timescale. Labels and other state are loaded from the target source.

Switch statements

EVT switch statements do not have implicit fallthrough; use CaseOrEq when you need it.

Opcode	Macro	Args	Description
`EVT_OP_SWITCH`	`Switch(expr)`	`expr`	Begins a switch over an expression resolved through `evt_get_variable`. Up to 8 switches may be nested.
`EVT_OP_SWITCH_CONST`	`SwitchConst(val)`	`val`	Begins a switch where the value is used as-is, without variable lookup.
`EVT_OP_CASE_EQ`	`CaseEq(val)`	`val`	Matches when the switch expression equals `val`.
`EVT_OP_CASE_NE`	`CaseNe(val)`	`val`	Matches when not equal.
`EVT_OP_CASE_LT`	`CaseLt(val)`	`val`	Matches when less than.
`EVT_OP_CASE_GT`	`CaseGt(val)`	`val`	Matches when greater than.
`EVT_OP_CASE_LE`	`CaseLe(val)`	`val`	Matches when less than or equal.
`EVT_OP_CASE_GE`	`CaseGe(val)`	`val`	Matches when greater than or equal.
`EVT_OP_CASE_DEFAULT`	`CaseDefault`	—	Matches unconditionally; used as the default case.
`EVT_OP_CASE_OR_EQ`	`CaseOrEq(val)`	`val`	Like `CaseEq`, but falls through to the next case until `EndCaseGroup`.
`EVT_OP_CASE_AND_EQ`	`CaseAndEq(val)`	`val`	Falls through only if `expr == val`; skips the group body otherwise.
`EVT_OP_CASE_FLAG`	`CaseFlag(val)`	`val`	Matches when the flag bit `val` is set on the switch expression.
`EVT_OP_END_CASE_GROUP`	`EndCaseGroup`	—	Closes a `CaseOrEq` / `CaseAndEq` fallthrough group.
`EVT_OP_CASE_RANGE`	`CaseRange(min, max)`	`min, max`	Matches when `min <= expr <= max` (inclusive).
`EVT_OP_BREAK_SWITCH`	`BreakSwitch`	—	Exits the current switch block.
`EVT_OP_END_SWITCH`	`EndSwitch`	—	Closes the switch statement.

Variables and assignment

EVT encodes variable references as large negative integers so they are distinguishable from literal values. The evt_get_variable and evt_set_variable functions decode the encoding at runtime.

Opcode	Macro	Args	Description
`EVT_OP_SET`	`Set(var, val)`	`var, val`	Sets `var` to the integer result of evaluating `val` through `evt_get_variable`.
`EVT_OP_SET_CONST`	`SetConst(var, const)`	`var, const`	Sets `var` to `const` as-is, skipping variable lookup.
`EVT_OP_SETF`	`SetF(var, val)`	`var, val`	Sets `var` to a fixed-point float value via `evt_get_float_variable`.

Integer arithmetic

All arithmetic opcodes read from and write back to a variable container.

Opcode	Macro	Args	Description
`EVT_OP_ADD`	`Add(var, val)`	`var, val`	`var += val`
`EVT_OP_SUB`	`Sub(var, val)`	`var, val`	`var -= val`
`EVT_OP_MUL`	`Mul(var, val)`	`var, val`	`var *= val`
`EVT_OP_DIV`	`Div(var, val)`	`var, val`	Integer division: `var /= val`
`EVT_OP_MOD`	`Mod(var, val)`	`var, val`	`var %= val`

Floating-point arithmetic

These operate on fixed-point floats using the same encoding as Float() and SetF.

Opcode	Macro	Args	Description
`EVT_OP_ADDF`	`AddF(var, val)`	`var, val`	`var += val` (float)
`EVT_OP_SUBF`	`SubF(var, val)`	`var, val`	`var -= val` (float)
`EVT_OP_MULF`	`MulF(var, val)`	`var, val`	`var *= val` (float)
`EVT_OP_DIVF`	`DivF(var, val)`	`var, val`	`var /= val` (float)

Bitwise operations

Opcode	Macro	Args	Description
`EVT_OP_BITWISE_AND`	`BitwiseAnd(var, val)`	`var, val`	`var &= val` — `val` is resolved through `evt_get_variable`.
`EVT_OP_BITWISE_AND_CONST`	`BitwiseAndConst(var, const)`	`var, const`	`var &= const` — `const` is used as-is.
`EVT_OP_BITWISE_OR`	`BitwiseOr(var, val)`	`var, val`	`var \|= val`
`EVT_OP_BITWISE_OR_CONST`	`BitwiseOrConst(var, const)`	`var, const`	`var \|= const` — `const` is used as-is.

Buffers and arrays

Scripts can read sequential data from a C pointer via buffer opcodes, or access named elements via array opcodes.

Opcode	Macro	Args	Description
`EVT_OP_USE_BUF`	`UseBuf(ptr)`	`s32*`	Sets the integer buffer pointer for subsequent `BufRead` calls.
`EVT_OP_BUF_READ1`	`BufRead1(v)`	`container`	Reads one `s32` from the buffer and advances the read position.
`EVT_OP_BUF_READ2`	`BufRead2(v1, v2)`	`container, container`	Reads two `s32` values.
`EVT_OP_BUF_READ3`	`BufRead3(v1, v2, v3)`	3 containers	Reads three `s32` values.
`EVT_OP_BUF_READ4`	`BufRead4(v1, v2, v3, v4)`	4 containers	Reads four `s32` values.
`EVT_OP_BUF_PEEK`	`BufPeek(idx, v)`	`index, container`	Reads the `s32` at `idx` without advancing the position.
`EVT_OP_USE_FBUF`	`UseFBuf(ptr)`	`f32*`	Identical to `UseBuf` for float buffers (same underlying pointer).
`EVT_OP_FBUF_READ1`	`FBufRead1(v)`	`container`	Reads one `f32`.
`EVT_OP_FBUF_READ2`	`FBufRead2(v1, v2)`	2 containers	Reads two `f32` values.
`EVT_OP_FBUF_READ3`	`FBufRead3(v1, v2, v3)`	3 containers	Reads three `f32` values.
`EVT_OP_FBUF_READ4`	`FBufRead4(v1, v2, v3, v4)`	4 containers	Reads four `f32` values.
`EVT_OP_FBUF_PEEK`	`FBufPeek(idx, v)`	`index, container`	Reads the `f32` at `idx` without advancing.
`EVT_OP_USE_ARRAY`	`UseArray(ptr)`	`s32*`	Loads an `s32` array for use with `ArrayVar(index)`.
`EVT_OP_USE_FLAGS`	`UseFlagArray(ptr)`	`s32*`	Loads a packed flag array for use with `ArrayFlag(index)`.
`EVT_OP_MALLOC_ARRAY`	`MallocArray(size, outVar)`	`length, s32*`	Allocates a new array of `size` elements. Scripts do not free this memory.

Script execution

Opcode	Macro	Args	Description
`EVT_OP_EXEC`	`Exec(script)`	`EvtScript*`	Spawns a new independent thread. The parent continues immediately.
`EVT_OP_EXEC_GET_TID`	`ExecGetTID(script, outVar)`	`EvtScript*, container`	Spawns a thread and stores its thread ID for later use with `KillThread`, `SuspendThread`, etc.
`EVT_OP_EXEC_WAIT`	`ExecWait(script)`	`EvtScript*`	Spawns a child thread and blocks until it returns. Local variables and flags are copied back on completion. This is a blocking instruction.
`EVT_OP_CALL`	`Call(func, ...)`	`*function, ...`	Calls a C `API_CALLABLE` function with optional arguments. Blocking if the function returns `ApiStatus_BLOCK`.

Thread management

Opcode	Macro	Args	Description
`EVT_OP_BIND_TRIGGER`	`BindTrigger(script, trigger, colliderID, unkA3, outVar)`	5 args	Registers a script to run when a trigger fires (e.g. `TRIGGER_FLOOR_TOUCH`). Only one thread runs per trigger at a time.
`EVT_OP_BIND_PADLOCK`	`BindPadlock(script, trigger, colliderID, itemList, unkA3, outVar)`	6 args	Like `BindTrigger`, but also specifies an item list for padlock interactions.
`EVT_OP_UNBIND`	`Unbind`	—	Removes the current thread’s trigger binding.
`EVT_OP_KILL_THREAD`	`KillThread(tid)`	`ScriptID`	Terminates the thread with the given ID.
`EVT_OP_SUSPEND_GROUP`	`SuspendGroup(group)`	`group`	Pauses all threads belonging to `group`.
`EVT_OP_RESUME_GROUP`	`ResumeGroup(group)`	`group`	Resumes all threads in `group`.
`EVT_OP_SUSPEND_OTHERS`	`SuspendOthers(group)`	`group`	Pauses all threads in `group` except the current one.
`EVT_OP_RESUME_OTHERS`	`ResumeOthers(group)`	`group`	Resumes all threads in `group` except the current one.
`EVT_OP_SUSPEND_THREAD`	`SuspendThread(tid)`	`ScriptID`	Pauses a specific thread by ID.
`EVT_OP_RESUME_THREAD`	`ResumeThread(tid)`	`ScriptID`	Resumes a specific thread by ID.
`EVT_OP_IS_THREAD_RUNNING`	`IsThreadRunning(tid, outVar)`	`ScriptID, container`	Sets `outVar` to true if a thread with the given ID is still alive.
`EVT_OP_SET_PRIORITY`	`SetPriority(priority)`	`priority`	Sets the current thread’s execution priority. Higher values run first.
`EVT_OP_SET_TIMESCALE`	`SetTimescale(scale)`	`timescale`	Sets a multiplier applied to `Wait` and `WaitSecs` durations.
`EVT_OP_SET_GROUP`	`SetGroup(group)`	`group`	Assigns the current thread to a group. See `EventGroupFlags` in `include/evt.h`.

Inline threads

These opcodes create threads inline within a script body rather than from an external EvtScript array.

Opcode	Macro	Description
`EVT_OP_THREAD`	`Thread`	Begins an inline thread block. The enclosed commands run as a new, independent thread.
`EVT_OP_END_THREAD`	`EndThread`	Closes an inline thread block.
`EVT_OP_CHILD_THREAD`	`ChildThread`	Begins an inline child thread block. The child is killed automatically when the parent dies.
`EVT_OP_END_CHILD_THREAD`	`EndChildThread`	Closes an inline child thread block.

Debug

These opcodes are stripped or become no-ops in the release build.

Opcode	Macro	Args	Description
`EVT_OP_DEBUG_LOG`	`EVT_DEBUG_LOG(str)`	`string`	Logs a string. Does nothing in the release build.
`EVT_OP_DEBUG_PRINT_VAR`	`DebugPrintVar(var)`	`expression`	Prints the name and value of a variable.

Reserved opcodes

Opcodes EVT_OP_92, EVT_OP_93, and EVT_OP_94 appear in the enum but are not yet documented in the decompilation.

Get Started

Contributing

EVT Scripting

Game Systems

Data Reference

EVT opcode reference: all bytecode instructions

Control flow

Switch statements

Variables and assignment

Integer arithmetic

Floating-point arithmetic

Bitwise operations

Buffers and arrays

Script execution

Thread management

Inline threads

Debug

Reserved opcodes

Build docs developers (and LLMs) love

Get Started

Contributing

EVT Scripting

Game Systems

Data Reference

Documentation Index

​Control flow

​Switch statements

​Variables and assignment

​Integer arithmetic

​Floating-point arithmetic

​Bitwise operations

​Buffers and arrays

​Script execution

​Thread management

​Inline threads

​Debug

​Reserved opcodes

Build docs developers (and LLMs) love

Control flow

Switch statements

Variables and assignment

Integer arithmetic

Floating-point arithmetic

Bitwise operations

Buffers and arrays

Script execution

Thread management

Inline threads

Debug

Reserved opcodes