SCM language

This section deals with the native SCM syntax of GTA 3 series, nothing other than III, VC, SA, LCS and VCS.
It may contain non-standard SCM definitions as R* hasn't published enough documentation about it yet.

On the occasion of the GTAIII's Tenth Anniversary, after a long period of darkness where we fell about the real SCM syntax, R* finally treated us by attaching part of its own original source code into the GTAIII Anniversary game, available for iOS and Android devices. As far back as 2001, a snip of some debugging scripts has been already provided with main.sc and debug.sc files. However, many secrets are unrevealed yet, thus some things cannot be documented fully and so they can be only guessed. The SCM format abbreviation is one of countless proofs of this inconvenience, which may stand for Script Multifile. Other doubts come with source files, whose SC extension appears to be very close to Mission SCript. Although we have enough information to suppose the currently unknown mysteries of the used language, we still have no safe clue about which was its original denomination. Furthermore, it is a matter of fact that R* developers have been left untouched the miss2 executable name of the GTA 3 series compiler since the chapter 2. In this connection, we could imagine the new language is a variant or an evolution of the GBHscript. In the ancient documentation by DMA (at present Rockstar North), GBH sound like the initials of the codename or the primordial name of GTA2, as the former is expressly stricken and overwritten by the latter (GBHGTA2script occurs twice, whereas GTA2script alone is quite recurrent). Therefore, we are almost sure to say the language name is most likely GTA3script. However, it is definitely based on BASIC.

Preliminary remarks

---

This article makes use of formatted codes to improve the reading comprehension. Note that:

• Square brackets mean everything inside may be omitted.
• Curly brackets denote the presence of useful codes but not necessarily needed.
• Vertical bars divide what can be chosen alternatively.
  
  

Fundamentals

Comments

A comment is an additional text that may be helpful for the code writer or other users, in short for the reader. It is the only part of the source code which gets always ignored when compiling.

Inline

An inline comment, denoted by // (two slashes), makes everything that follows some plain text:

[...] // Some inline comment

Multiline

A multiline comment embraces a particular area of the source code, starting by the opening tag /* (slash and asterisk) and ending with */ (asterisk and slash):

[...]
/*
 * Some multiline comment
 * ...
 */
[...]

Currently, more than one multiline comment is allowed per line:

[...] /* Some inline comment */ [...] /* Some inline comment */ [...]

Highlighters

Highlighters behaviour sounds trivial, that's to say they simply highlight one or more arguments per command within round brackets, individually or together. However, a comma can be used aswell to distinguish each argument. In , they appear to be used only for SETUP_ZONE_PED_INFO (in a various order) and GXT keys:

SETUP_ZONE_PED_INFO FISHFAC DAY (0) 0 0 0 (0 0 0 0) 0
PRINT_BIG (T4X4_1) 5000 2

Scopes

Scopes are delimited by curly brackets (or multiline brackets) which act like a local variable scopes. Essentially, they enclose the code where local variables are used, including timers. They can be opened and closed many times in a script:

{
    [...]
}

Limit

Scopes cannot be nested.

Labels

A label is a sequence of characters which identifiy a location of the source code useful for jumps. It can be accessed by any part of the source code. To define a label just append : (colon) to its name:

[...]

{lblname}:
[...]

At the compiling time, they are automatically converted into an offset.

Variables

A variable is a storage location assigned to a symbolic name which contains a value of any type.

Value

A value represents any data of any type it is.

Scope

---

The usage of a variable depends on the scope, that is the context where a specific variable is declared. At this point, we can distinguish the global and local scope.

Global

The global scope grasps the whole source code. Variables defined as globals are visible in any script. They are declared by appending the VAR prefix.

Local

---

The local scope wraps a localized part of the source code. Variables defined as locals are visible only in the code enclosed by curly brackets. You can put them everywhere and as many times as you want in the source code. They are declared by appending the LVAR prefix.

Timers

A timer is a special local variable whose value rises automatically. It starts incrementing since the beginning of the script where it has been placed and grows endlessly. There are 2 usable timers which are already defined as TIMERA and TIMERB, therefore they do not need to be declared.

Data types

---

Among the available types, some are equivalent to the most known programming types. Their length is up to 4, 8 and 16 bytes. Each type is appended as a suffix in the variable declaration.

INT

The INT type handles 32-bit signed integers. It is also used to store values with less bytes, such as a bool, a char and a short int.

FLOAT

The FLOAT type handles 32-bit floating-points. As it normally does, decimal precision of a float is usually stuck to 6 digits beyond which it may get lost.

TEXT_LABEL

The TEXT_LABEL type handles 8-byte strings. Generally, a string is an array of 1-byte characters. It requires 7 characters plus the null-terminator (a blank byte meaning the end of the string). It is used to hold GXT keys (those of town zones, interiors, help textes or dialogue subtitles) script names or any short string.

Limit

TEXT_LABEL variables are supported in and .

STRING

The STRING type handles 16-byte strings. Like the previous, this type holds 15 characters plus the null-terminator. It is used to store model and texture names of player clothes, animation names or any long string. It may be a ghost type as later R* compilers might choose between the two string types automatically according to the length of the string itself.

Limit

STRING variables and values are supported in .

REFERENCE

The REFERENCE type handles 16-byte strings. They can refer to either a label name or a file name. While inside

Limit

REFERENCE variables aren't available.

NUMBER (pseudo)

The NUMBER type handles 32-bit signed integers or 32-bit floating-points. It is used only to assign and compare numbers to INT or FLOAT variables. It is a pseudo type of INT or FLOAT.

CONSTANT (pseudo)

The CONSTANT type handles 32-bit signed integers. It is used only to assign and compare constants to INT variables regarding model identifiers, task statuses, ped events and such. It is a pseudo type of INT.

Limit

The assignment and comparison of CONSTANT values are supported since .

BUFFER

The BUFFER type handles 32-byte strings or larger, depending on how many continuous parameters of the same type there are, each of which occupies 32 bytes. It can hold up to 127 characters plus the null-terminator, after which another BUFFER argument may begin. Strings of such type must be put within quotation marks:

SAVE_STRING_TO_DEBUG_FILE "32B-128B TEXT"

Limits

BUFFER values are supported since .

BUFFER variables aren't available.

VARLEN

The VARLEN type handles N-byte strings. It holds N characters plus the null-terminator. Strings of this type mustn't exceed 255 characters.

Limits

VARLEN values are supported since .

VARLEN variables aren't available.

Declaration

---

Defining a variable means assigning a token string to a memory cell at the compiling time. Variables must be declared in the following manner:

{varscope}_{vartype} {varname0}[,] [... {varnameN}]

As mentioned in the sections above, local variables have to be put within curly brackets:

{
    {varscope}_{vartype} {varname0}[,] [... {varnameN}]

    [...]
}

Inline variable declaration is allowed, you just have to separate them by spaces or tabulations. Adding a preceding comma before these characters is optional.

Limit

Whereas the variable buffer is limited, you can declare a certain amount of globals and locals. INT and FLOAT) types take 1 variable, while TEXT_LABEL and STRING types occupy respectively 2 and 4 variables to store their data (have a look here for further details).

Arrays

A array is a collection of variables having the same type which can be accessed by an index, a 1-based integer lesser than or equal to the size specified, enclosed by square brackets:

{
    {varscope}_{vartype} {varname0}{[arrsize0]}[,] [... {varnameN}{[arrsizeN]}]

    [...]
}

Limits

The usage of arrays is allowed since .

Variable indices are quite buggy in and therefore unrecommended, but they are fully supported since .

Handles

A handle is an univocal identifier assigned to a game entity. It is given by the following statement:

short nHandle = (iEntityIndexInPool << 8) | ucEntityFlag;

R* compiler won't let you assign different entity types to the same variable or using a variable which hasn't been assigned to any CREATE_* or ADD_* entity commands.

Operators

In general, an operator is a token string that represents a math calculation or an operation of any other kind, in order to make the code understanding clearer at a glance.

Arithmetic

Arithmetic operators compute some of the most common algebric calculations between either a variable and a value or two variables. As well as in some programming language happens, CONSTANT, TEXT_LABEL and STRING types are free from these operators, except for the basic assigment (see also Operators composition):

Operator	Name		Syntax	Description
=	Assignment		expr0 = expr1	Store expr1 to expr0
+	Addition		expr0 + expr1	Add expr1 to expr0
-	Subtraction		expr0 - expr1	Subtract expr1 from expr0
*	Multiplication		expr0 * expr1	Multiply expr0 by expr1
/	Division		expr0 / expr1	Divide expr0 by expr1
+@	Timed addition		expr0 +@ expr1	Multiply expr2 by delta time and add the result to expr1
-@	Timed subtraction		expr0 -@ expr1	Multiply expr2 by delta time and subtract the result from expr1
++	Increment	Pre[*]	++ expr0	Increment expr0 by 1 and store the result to expr0
		Post	expr0 ++
--	Decrement	Pre[*]	-- expr0	Decrement expr0 by 1 and store the result to expr0
		Post	expr0 --

Note

^ Pre and post increments have no difference unlike what you would expect.

Yet, you can put the assignment and algebric operators together inline as follows:

Operators	Name	Syntax	Description
= +	Addition and assignment	expr0 = expr1[*] + expr2	Add expr2 to expr1 and store the result to expr0
= -	Subtraction and assignment	expr0 = expr1[*] - expr2	Subtract expr2 from expr1 and store the result to expr0
= *	Multiplication and assignment	expr0 = expr1[*] * expr2	Multiply expr1 by expr2 and store the result to expr0
= /	Division and assignment	expr0 = expr1[*] / expr2	Divide expr1 by expr2 and store the result to expr0
= +@	Timed addition and assignment	expr0 = expr1[*] +@ expr2	Multiply expr2 by delta time, add the result to expr1 and store everything to expr0
= -@	Timed subtraction and assignment	expr0 = expr1[*] -@ expr2	Multiply expr2 by delta time, subtract the result from expr1 and store everything to expr0

Note

^ expr1 can represent expr0 too.

Limit

Multiple algebric operators per line are not allowed.

Compound assignment

Compound assignment operators store values or variable content to other variables having a particular type afterwards the computation of an arithmetic operation, to squeeze the code and clear it up from granted repetitions:

Operator	Name	Syntax	Description
+=	Addition assignment	expr0 += expr1	Add expr1 to expr0 and store the result to expr0
-=	Subtraction assignment	expr0 -= expr1	Subtract expr1 from expr0 and store the result to expr0
*=	Multiplication assignment	expr0 *= expr1	Multiply expr0 by expr1 and store the result to expr0
/=	Division assignment	expr0 /= expr1	Divide expr0 by expr1 and store the result to expr0
+=@	Timed addition assignment	expr0 +=@ expr1	Multiply expr1 by delta time, add the result to expr0 and store everything to expr0
-=@	Timed subtraction assignment	expr0 -=@ expr1	Multiply expr1 by delta time, subtract the result from expr0 and store everything to expr0

Uncompounded assignment

Uncompounded assignment operators are those on their own, or rather they are neither derivable nor decomposable similarly as those compounds:

Operator	Name	Syntax	Description
=#	Cast assignment	expr0 =# expr1	Cast expr1 to any other type and store the result to expr0

Limit

Supported conversions are FLOAT to INT and INT to FLOAT.

Logical

Logical operators influence the way conditions are evalueted and enable to test more of them at a time. More than anything, they are built-in statements:

Operator	Name	Syntax	Description
NOT	Logical negation	IF NOT condition0	Test if condition0 is false
AND	Logical conjunction	IF condition0 AND condition8	Test if both condition0 and conditionN are true
OR	Logical disjunction	IF condition0 OR condition8	Test if either condition0 or conditionN is true

Comparison

Comparison operators test the truth or falsity of the relation between either a variable and a value, a value and a variable or two variables:

Operator	Name	Syntax	Description
=	Equal to	IF expr0 = expr1	Test if expr0 and expr1 are equal
>	Greater than	IF expr0 > expr1	Test if expr0 is greater than expr1
<	Lesser than	IF expr0 < expr1	Test if expr0 is lesser than expr1
>=	Greater than or equal to	IF expr0 >= expr1	Test if expr0 is greater than or equal to expr1
<=	Lesser than or equal to	IF expr0 <= expr1	Test if expr0 is lesser than or equal to expr1

Theorically, STRING values should be compared with the first operator only, but the presence of COMPARE_STRING increase the doubts concerning the existence of such operator for this type.

Commands

A command is a symbolic name associated to an opcode which executes a portion of code that specifies the operation to be performed by passing zero or more arguments. Opcodes do not return values that can be assigned to a variable, even though the boolean flag is kept whenever they are used as conditions. It follows the common programming syntax adopted for procedure or function calls:

{commandname} [{anyvalue0|varname0} ... {anyvalueN|varnameN}]

Alternatives

Alternative commands are those which are basically overloaded on the bases of different argument types:

• :
  • SET (=)
  • CSET (=#)
  • ADD_THING_TO_THING (+=)
  • SUB_THING_FROM_THING (-=)
  • MULT_THING_BY_THING (*=)
  • DIV_THING_BY_THING (/=)
  • IS_THING_EQUAL_TO_THING (=)
  • IS_THING_NOT_EQUAL_TO_THING (NOT =)
  • IS_THING_GREATER_THAN_THING (>)
  • IS_THING_GREATER_OR_EQUAL_TO_THING (>=)
  • ADD_THING_TO_THING_TIMED (+=@)
  • SUB_THING_FROM_THING_TIMED (-=@)
  • ABS
• :
  • IS_TEXT_LABEL_NULL
  • IS_STRING_NULL
  • IS_BIT_SET
  • SET_BIT
  • CLEAR_BIT
  • COMPARE_STRING

This section is incomplete. You can help by fixing and expanding it.

Internals

Internal commands are those which have special characteristics and are handled internally by the compiler:

• :
  • GOTO
  • GOTO_IF_FALSE
  • MISSION_END
  • START_NEW_SCRIPT
  • ANDOR
  • LAUNCH_MISSION
  • PLAYER_MADE_PROGRESS
  • SET_PROGRESS_TOTAL^[*]
  • REGISTER_MISSION_GIVEN
  • REGISTER_MISSION_PASSED
  • SCRIPT_NAME
  • LOAD_AND_LAUNCH_MISSION
  • LOAD_AND_LAUNCH_MISSION_INTERNAL
  • SET_TOTAL_NUMBER_OF_MISSIONS^[*]
• :
  • REGISTER_ODDJOB_MISSION_PASSED
• :
  • GOTO_IF_TRUE
  • GOSUB_FILE
• :
  • CREATE_COLLECTABLE1
  • SET_COLLECTABLE1_TOTAL^[*]
• :
  • LOAD_AND_LAUNCH_MISSION_EXCLUSIVE
• :
  • CALL
  • CALLB
• 
  • INIT_TABLE_OF_GOTO
  • APPEND_GOTO_TO_TABLE
• :
  • SET_COLLECTABLE2_TOTAL

Note

^ The argument of these commands must be set respectively according to:

• The sum of PLAYER_MADE_PROGRESS values;
• The amount of REGISTER_MISSION_PASSED (those that doesn't have an immediate value are excluded) and REGISTER_ODDJOB_MISSION_PASSED;
• The amount of CREATE_COLLECTABLE1.

If the argument of the listed commands differs from that expected, a 0-value must be passed.

This section is incomplete. You can help by fixing and expanding it.

WAIT

WAIT skips the execution of a script according to some milliseconds after which it will resume again. Indeed, it is absolutely necessary into infinite loops or those that break after more than one frame, such as the WHILE statement. In this case, a INT equal to 0 is passed.

GOTO

GOTO jumps to the label of any location of the source code. It is also used internally to build other statements or singularly but then it mustn't point off the current context:

// File: any.sc

jump0:
GOTO jumpN

// File: any.sc

jumpN:
GOTO jump0

ANDOR

ANDOR set out the way the comparison among more conditions have to occur (see also Comparing rule).

GOTO_IF_TRUE

GOTO_IF_TRUE operates in conjunction with ANDOR and jumps to a label if the returned boolean flag is true.

GOTO_IF_FALSE

Unlike GOTO_IF_TRUE, GOTO_IF_FALSE jumps to the disired label only if the comparison returns false.

SCRIPT_NAME

SCRIPT_NAME simply associates an unique name to the parent script.

Note

R* compiler doesn't enable you to associate a name previously used.

SAVE_STRING_TO_DEBUG_FILE

SAVE_STRING_TO_DEBUG_FILE accepts an argument which can admit up to 127 characters plus the null-terminator. In the compiling process, the argument is skipped but its string is copied to a predefined 128-bytes buffer, compiled afterwards. In , these are the predetermined bytes that seem to do nothing:

00 00 41 00 09 2E 00 00 00 00 00 00 00 00 00 00 
09 2E 00 00 00 00 00 00 1C FB 12 00 D8 A8 41 00
00 00 41 00 09 2E 00 00 00 00 00 00 01 00 00 00 
09 2E 00 00 00 00 00 00 1C FB 12 00 D8 A8 41 00
00 00 41 00 09 2E 00 00 00 00 00 00 02 00 00 00 
09 2E 00 00 00 00 00 00 1C FB 12 00 D8 A8 41 00
00 00 41 00 09 2E 00 00 00 00 00 00 03 00 00 00 
09 2E 00 00 00 00 00 00 1C FB 12 00 D8 A8 41 00

Dynamic values within a block are marked in grey, while those which differs among each block are coloured in blue. Possibly rubbish data.

Constants

A constant is a symbolic name associated to a specific value. When compiling, their caption is converted in the assigned value. In and , they are hardcoded as everything inside the compiler. Since , names and identifiers of objects within OBJS and TOBJ blocks are loaded from every IDE file defined into gta_vc.dat, then those of vehicles and pedestrians within PEDS and CARS blocks are retrieved from default.ide. In , they are listed into TXT files, whose name follows the Pascal Case (eg. AudioEvents.txt). These files respect the syntax below:

{constname0} {constvalue0}

{constnameN} {constvalueN}

Constant names and values are divided by as many spaces or tabulations as you want. Constant lines are distinguished by two \n (new line) characters. The model names which aren't assigned to a constant are still valid (see also Identifiers). Keep in mind arguments of some commands having the CONSTANT type accept only constant values of a single namespace.

Formatting

Everything is case-insensitive, that means the uppercase and lowercase letters are computed as the same character. Usually, the source code is formatted as shown in this table:

	Uppercase	Lowercase
Label		X
Declaration	X
Variable		X
Command	X
Constant	X
Statement	X

Compiling

Structure

The source code is split up into several SC files which comprehend main file, foreign gosubs, subscripts, mission scripts, and trigger scripts. These files can be included more times because they are actually processed once.

Main file

---

The main file is the most significant part of the whole source. It can include many script files and/or embedded gosubs, scripts or functions. Originally, it is characterized by the absence of the local scope. It must be put outside the directory, having the same name as the main script file, where all other foreign scripts must be. R* compiler will search into subfolders too:

<directory>
| main
|  | gosub
|  |  |- gosub1.sc
|  |  \- gosubN.sc
|  | subscript
|  |  |- subscript1.sc
|  |  \- subscriptN.sc
|  | mission_guy
|  |  |- mission_guy1.sc
|  |  \- mission_guyN.sc
|  |- gosub.sc
|  |- subscript.sc
|  \- mission.sc
\- main.sc

Foreign gosubs

---

Foreign gosubs (also called subroutines) are main extension files. They are called using the GOSUB_FILE command which jumps to a specific label and executes some code that returns back to the place where it has been called with RETURN. You are able to specify the gosub label to start jumping at aswell:

// File: main.sc

GOSUB_FILE gosub0 gosub.sc

// File: gosub.sc

gosub0:
{
    [...]
}
RETURN

Limit

Foreign gosubs were introduced since . They were unused in and got removed in , but then they were reimplemented in and .

Gosubs

As mentioned, gosubs are also embedded in any script file. They follow almost the same rules, except they are called by GOSUB and can actually inehrit the local scope of the parent script:

// File: any.sc

GOSUB gosub0

// File: any.sc

gosub0:
{
    [...]
}
RETURN

Note

R* compiler doesn't take care if the code within a scope jumps to a gosub inside which another scope is declared. It is strongly recommended to pay attention at this issue or you will fall down into an irreparable local variable mismatch.

Subscripts

---

Subscripts are code blocks which take part of a queue of other scripts and are allocated over the memory by LAUNCH_MISSION. They are denoted by the presence of MISSION_START at the very top of the mission file. As long as they aren't ended with MISSION_END, their execution never expires till the end of the game process. Each one works independently, even though they are able to share global variables:

// File: main.sc

LAUNCH_MISSION subscript.sc

// File: subscript.sc

MISSION_START

[VAR_{vartype} {varname0}[,] [... {varnameN}]]

SCRIPT_NAME main

subscript_loop:
{
    [LVAR_{vartype} {varname0}[,] [... {varnameN}]]

    [...]
}
//GOTO subscript_loop
MISSION_END

Note

MISSION_START is a special and fake directive that isn't assigned to any command. R* compiler will notify an error if it isn't placed at the first line of a subscript or a mission script.

Scripts

As for gosubs, scripts can be embedded everywhere in a script file. They are started by START_NEW_SCRIPT which has an undefined amount of arguments, whose type must match with those of each local variable of the starting script in order to be passed, else the compilation will interrupt. Unlike subscripts, they get terminated by TERMINATE_THIS_SCRIPT or TERMINATE_ALL_SCRIPTS_WITH_THIS_NAME (elsewhere in another script):

// File: any.sc

START_NEW_SCRIPT script [{anyvalue0|varname0} ... {anyvalueN|varnameN}]

// File: any.sc

script:
{
    SCRIPT_NAME script

script_loop:

    [LVAR_{vartype} {varname0}[,] [... {varnameN}]]

    [...]

    //GOTO script_loop
    TERMINATE_THIS_SCRIPT
}

Notes

Scripts must have a local scope.

Script commands must be inserted within or after the local scope.

Since , the opening curly bracket must be put before the script label when more arguments are passed.

Functions

This section is incomplete. You can help by fixing and expanding it.

Mission scripts

---

Mission scripts are those subscripts which are responsible for the presence of a storyline in the game. When they are launched with LOAD_AND_LAUNCH_MISSION, the mission is loaded in the mission block, allocated over the memory and the script pointer is moved to the corresponding mission offset. Do not forget to begin a mission script with MISSION_START and end it with MISSION_END:

// File: main.sc

LOAD_AND_LAUNCH_MISSION mission.sc

// File: mission.sc

MISSION_START

GOSUB mission_start

IF HAS_DEATHARREST_BEEN_EXECUTED
    GOSUB mission_failed
ENDIF

GOSUB mission_cleanup

MISSION_END

[VAR_{vartype} {varname0}[,] [... {varnameN}]]

mission_start:

REGISTER_MISSION_GIVEN
SCRIPT_NAME mission

// Variables initialization

{
    [LVAR_{vartype} {varname0}[,] [... {varnameN}]]

    [...]
}
GOTO mission_passed

mission_failed:
[...]
RETURN

mission_passed:
REGISTER_MISSION_PASSED mission
//PLAYER_MADE_PROGRESS 1
[...]
RETURN

mission_cleanup:
// Mark everything as no longer needed
[...]
RETURN

Few missions doesn't need to be executed twice or more times because they may just initialize some global variables defined in the main script or launch the intro mission. For this reason, here comes the use of LOAD_AND_LAUNCH_MISSION_EXCLUSIVE:

// File: main.sc

LOAD_AND_LAUNCH_MISSION_EXCLUSIVE initial.sc
LOAD_AND_LAUNCH_MISSION_EXCLUSIVE intro.sc

Note

Esclusive missions are never launched in the source code. It's likely, it was an idea not came to the end successfully.

Limits

LOAD_AND_LAUNCH_MISSION_EXCLUSIVE is available only in and .

R* compiler won't let you using more than 2 LOAD_AND_LAUNCH_MISSION_EXCLUSIVE.

Trigger scripts

---

This section is incomplete. You can help by fixing and expanding it.

Statements

As usual, the evolution of something implies its development over the years. Alongside, the statements implementation has been distributed equally into every chapter. Their definitions are similar to those used in pseudocodes resulting in a raw source code. However, you are still able to build your own control flows:

ANDOR {value}
    [NOT] {condition0}
    [[NOT] {condition8}]
GOTO_IF_FALSE ELSE
    {consequence}
    [GOTO ENDIF]
ELSE:
    [{alternative}
ENDIF:]

Note

It's likely, user-made control flows weren't intended to be usable because R* compiler cannot recognize an equal to rather than an assignment operator.

IF

IF is one of the most widespread conditional statements which executes some codes by evaluating a boolean flag, the returning value of one or more conditions. According to the returning value, either the consequence or the alternative will be performed. The condition result can be inverted by appending the NOT logical operator before. More conditions require the use of the remaining logical operators, they are AND, when verifying if all checks are true, and OR, while testing if one of all checks is true. The syntax below summarize the whole explanation:

IF [NOT] {condition0}
[AND|OR [NOT] {condition8}]
    {consequence}
[ELSE
    {alternative}]
ENDIF

Limit

More than 8 conditions per statement are't allowed.

IFNOT

IFNOT is a variation of the IF statement as already stated. As opposed to its closest relative, the conditions evaluetion is reversed, that is the consequence is perfomed when the boolean flag is false, else the alternative is executed:

IFNOT [NOT] {condition0}
[AND|OR [NOT] {condition8}]
    {consequence}
[ELSE
    {alternative}]
ENDIF

Limit

It is supported in , and .

WHILE

Alike the IF construct, WHILE is a conditional statement. The only difference consists in how it performs the consequence, that is it loops every line of code built into if the boolean flag is true:

WHILE [NOT] {condition0}
[AND|OR [NOT] {condition8}]
    {consequence}
ENDWHILE

WHILENOT

WHILENOT acts seemingly like the WHILE statement, as all condition truths are inverted and therefore the consequence is performed over and over again until the boolean flag becomes true:

WHILENOT [NOT] {condition0}
[AND|OR [NOT] {condition8}]
    {consequence}
ENDWHILE

Limit

It is supported in , and .

REPEAT

Similar to the WHILE construct, REPEAT iterates the consequence repeatedly depending on a 0-value incremental variable which rises till the times specified:

REPEAT {times} {varname}
    {consequence}
ENDREPEAT

Limits

It is supported since .

The times must be positive.

The code will be read at least once in any case.

CASE

Basically, CASE is a group of concatenated IF statements. When a condition is false the next case gets performed, otherwise the consequence is executed and the code jumps to the end of the construct. If none of the cases is true, an ELSE clause may be carried out:

CASE {varname}
    WHEN {value0}
        {consequence}
    [WHEN {valueN}
        {consequence}]
    [ELSE
        {alternative}]
ENDCASE

Limits

It is supported since .

The WHEN clause allows the use of integer values only.

In , values must be sorted.

Multiple cases per consequence aren't allowed.

Decompiling

Structure

For further information about the SCM file format, read this article. Take into account the compiling order of each SC file is main file - foreign gosubs - subscripts - mission scripts apart from the reading order of the commands used to include them. Trigger scripts are compiled individually into the script.img file. On the other hand, functions are compiled like gosubs.

Identifiers

Undefined constants of model identifiers, whose name refers to a DFF which is presumably archived into any of the IMGs, loaded by the game, are overwritten by a decrementing value in the order they get compiled. These model names are then put into the second segment of the SCM header. Those of mission scripts and trigger scripts respect the same rule except the fact they are turned into a 0-based growing identifier, while exclusive mission scripts are launched by a negative identifier.

Offsets

An offset is a 32-bit signed integer which points to a location of the source code. Those within the main file, foreign gosubs and subscripts are absolute offsets that start from the beginning of the main script, while the ones inside mission scripts and trigger scripts are relative offsets starting from their beginning. The offset is related to global variables aswell, whose interval goes from 8 and ends to FFFC, each one is aligned to the nearest 4 bytes.

Variables

The following table shows the variables range of the local scope for each game version:

Context
Foreign gosub/Gosub	0-15	0-15	n/a	0-95	0-95
Subscript/Script	0-15	0-15	0-31	0-95	0-95
Mission script	0-15	0-15	0-1023	0-95	0-95
Trigger script	n/a	n/a	0-31	n/a	n/a
Function	n/a	n/a	n/a	0-95	0-95
Timer	16-17	16-17	32-33	10-11?	254-255

Operators composition

As far as you wouldn't know, SCM's operators always take two operands to compute an operation. Their composition is listed below:

Operator/s	Name		Syntax	Composition
++	Increment	Pre	++ expr0	expr0 += 1
		Post	expr0 ++
--	Decrement	Pre	-- expr0	expr0 -= 1
		Post	expr0 --
= +	Addition and assignment		expr0 = expr1 + expr2	expr0 = expr1 expr0 += expr2
= -	Subtraction and assignment		expr0 = expr1 - expr2	expr0 = expr1 expr0 -= expr2
= *	Multiplication and assignment		expr0 = expr1 * expr2	expr0 = expr1 expr0 *= expr2
= /	Division and assignment		expr0 = expr1 / expr2	expr0 = expr1 expr0 /= expr2
= +@	Timed addition and assignment		expr0 = expr1 +@ expr2	expr0 = expr1 expr0 +=@ expr2
= -@	Timed subtraction and assignment		expr0 = expr1 -@ expr2	expr0 = expr1 expr0 -=@ expr2

Opcodes

An opcode is a 16-bit unsigned integer referring to a portion of code the game executes when it is called by passing an undefined or absent amount of arguments. The maximum number of available opcodes is 0x7FFF, since the last bit (0x8000) is set whenever they are used as negative conditions (those with the NOT logical operator).

Arguments

An argument is some data given as input to an opcode. Normally, opcodes have a defined amount of arguments up to 32. Those not, such as START_NEW_SCRIPT, can pass as many arguments as the available local variables are, except timers. This limitation is game specific.

Specials

Here is the list of all special commands and their relative specifications:

Legend:

• Variable:
  • V, VALUE
  • G, GLOBAL
  • L, LOCAL

• Type:
  • I, INT
  • F, FLOAT
  • T, TEXT_LABEL
  • S, STRING
  • O, REFERENCE
  • N, NUMBER
  • C, CONSTANT
  • B, BUFFER
  • V, VARLEN

List:

Command		Opcode	Arg. count	Arguments
				1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	...	32
MISSION_START[*]			0
GOTO[*]		0002	1	VR
=	SET_VAR_INT	0004	2	GI	VI
	SET_VAR_FLOAT	0005		GF	VF
	SET_LVAR_INT	0006		LI	VI
	SET_LVAR_FLOAT	0007		LF	VF
+=	ADD_VAL_TO_INT_VAR	0008	2	GI	VI
	ADD_VAL_TO_FLOAT_VAR	0009		GF	VF
	ADD_VAL_TO_INT_LVAR	000A		LI	VI
	ADD_VAL_TO_FLOAT_LVAR	000B		LF	VF
-=	SUB_VAL_FROM_INT_VAR	000C	2	GI	VI
	SUB_VAL_FROM_FLOAT_VAR	000D		GF	VF
	SUB_VAL_FROM_INT_LVAR	000E		LI	VI
	SUB_VAL_FROM_FLOAT_LVAR	000F		LF	VF
*=	MULT_INT_VAR_BY_VAL	0010	2	GI	VI
	MULT_FLOAT_VAR_BY_VAL	0011		GF	VF
	MULT_INT_LVAR_BY_VAL	0012		LI	VI
	MULT_FLOAT_LVAR_BY_VAL	0013		LF	VF
/=	DIV_INT_ANY_BY_VAL	0014	2	GI	VI
	DIV_FLOAT_VAR_BY_VAL	0015		GF	VF
	DIV_INT_LVAR_BY_VAL	0016		LI	VI
	DIV_FLOAT_LVAR_BY_VAL	0017		LF	VF
>	IS_INT_VAR_GREATER_THAN_NUMBER	0018	2	GI	VN
	IS_INT_LVAR_GREATER_THAN_NUMBER	0019		LI	VN
	IS_NUMBER_GREATER_THAN_INT_VAR	001A		VN	GI
	IS_NUMBER_GREATER_THAN_INT_LVAR	001B		VN	LI
	IS_INT_VAR_GREATER_THAN_INT_VAR	001C		GI	GI
	IS_INT_LVAR_GREATER_THAN_INT_LVAR	001D		LI	LI
	IS_INT_VAR_GREATER_THAN_INT_LVAR	001E		GI	LI
	IS_INT_LVAR_GREATER_THAN_INT_VAR	001F		LI	GI
	IS_FLOAT_VAR_GREATER_THAN_NUMBER	0020		GF	VN
	IS_FLOAT_LVAR_GREATER_THAN_NUMBER	0021		LF	VN
	IS_NUMBER_GREATER_THAN_FLOAT_VAR	0022		VN	GF
	IS_NUMBER_GREATER_THAN_FLOAT_LVAR	0023		VN	LF
	IS_FLOAT_VAR_GREATER_THAN_FLOAT_VAR	0024		GF	GF
	IS_FLOAT_LVAR_GREATER_THAN_FLOAT_LVAR	0025		LF	LF
	IS_FLOAT_VAR_GREATER_THAN_FLOAT_LVAR	0026		GF	LF
	IS_FLOAT_LVAR_GREATER_THAN_FLOAT_VAR	0027		LF	GF
>=	IS_INT_VAR_GREATER_OR_EQUAL_TO_NUMBER	0028	2	GI	VN
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_NUMBER	0029		LI	VN
	IS_NUMBER_GREATER_OR_EQUAL_TO_INT_VAR	002A		VN	GI
	IS_NUMBER_GREATER_OR_EQUAL_TO_INT_LVAR	002B		VN	LI
	IS_INT_VAR_GREATER_OR_EQUAL_TO_INT_VAR	002C		GI	GI
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_INT_LVAR	002D		LI	LI
	IS_INT_VAR_GREATER_OR_EQUAL_TO_INT_LVAR	002E		GI	LI
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_INT_VAR	002F		LI	GI
	IS_FLOAT_VAR_GREATER_OR_EQUAL_TO_NUMBER	0030		GF	VN
	IS_FLOAT_LVAR_GREATER_OR_EQUAL_TO_NUMBER	0031		LF	VN
	IS_NUMBER_GREATER_OR_EQUAL_TO_FLOAT_VAR	0032		VN	GF
	IS_NUMBER_GREATER_OR_EQUAL_TO_FLOAT_LVAR	0033		VN	LF
	IS_FLOAT_VAR_GREATER_OR_EQUAL_TO_FLOAT_VAR	0034		GF	GF
	IS_FLOAT_LVAR_GREATER_OR_EQUAL_TO_FLOAT_LVAR	0035		LF	LF
	IS_FLOAT_VAR_GREATER_OR_EQUAL_TO_FLOAT_LVAR	0036		GF	LF
	IS_FLOAT_LVAR_GREATER_OR_EQUAL_TO_FLOAT_VAR	0037		LF	GF
=	IS_INT_VAR_EQUAL_TO_NUMBER	0038	2	GI	VN
	IS_INT_LVAR_EQUAL_TO_NUMBER	0039		LI	VN
	IS_INT_VAR_EQUAL_TO_INT_VAR	003A		GI	GI
	IS_INT_LVAR_EQUAL_TO_INT_LVAR	003B		LI	LI
	IS_INT_VAR_EQUAL_TO_INT_LVAR	003C		GI	LI
	IS_FLOAT_VAR_EQUAL_TO_NUMBER	0042		GF	VN
	IS_FLOAT_LVAR_EQUAL_TO_NUMBER	0043		LF	VN
	IS_FLOAT_VAR_EQUAL_TO_FLOAT_VAR	0044		GF	GF
	IS_FLOAT_LVAR_EQUAL_TO_FLOAT_LVAR	0045		LF	LF
	IS_FLOAT_VAR_EQUAL_TO_FLOAT_LVAR	0046		GF	LF
GOTO_IF_FALSE[*]		004D	1	VR
TERMINATE_THIS_SCRIPT		004E	0
MISSION_END
START_NEW_SCRIPT[*]		004F	1	VR	_ _ _
GOSUB		0050	1	VR
RETURN		0051	0
+=	ADD_INT_VAR_TO_INT_VAR	0058	2	GI	GI
	ADD_FLOAT_VAR_TO_FLOAT_VAR	0059		GF	GF
	ADD_INT_LVAR_TO_INT_LVAR	005A		LI	LI
	ADD_FLOAT_LVAR_TO_FLOAT_LVAR	005B		LF	LF
	ADD_INT_VAR_TO_INT_LVAR	005C		LI	GI
	ADD_FLOAT_VAR_TO_FLOAT_LVAR	005D		LF	GF
	ADD_INT_LVAR_TO_INT_VAR	005E		GI	LI
	ADD_FLOAT_LVAR_TO_FLOAT_VAR	005F		GF	LF
-=	SUB_INT_VAR_FROM_INT_VAR	0060	2	GI	GI
	SUB_FLOAT_VAR_FROM_FLOAT_VAR	0061		GF	GF
	SUB_INT_LVAR_FROM_INT_LVAR	0062		LI	LI
	SUB_FLOAT_LVAR_FROM_FLOAT_LVAR	0063		LF	LF
	SUB_INT_VAR_FROM_INT_LVAR	0064		LI	GI
	SUB_FLOAT_VAR_FROM_FLOAT_LVAR	0065		LF	GF
	SUB_INT_LVAR_FROM_INT_VAR	0066		GI	LI
	SUB_FLOAT_LVAR_FROM_FLOAT_VAR	0067		GF	LF
*=	MULT_INT_VAR_BY_INT_VAR	0068	2	GI	GI
	MULT_FLOAT_VAR_BY_FLOAT_VAR	0069		GF	GF
	MULT_INT_LVAR_BY_INT_LVAR	006A		LI	LI
	MULT_FLOAT_LVAR_BY_FLOAT_LVAR	006B		LF	LF
	MULT_INT_VAR_BY_INT_LVAR	006C		GI	LI
	MULT_FLOAT_VAR_BY_FLOAT_LVAR	006D		GF	LF
	MULT_INT_LVAR_BY_INT_VAR	006E		LI	GI
	MULT_FLOAT_LVAR_BY_FLOAT_VAR	006F		LF	GF
/=	DIV_INT_VAR_BY_INT_VAR	0070	2	GI	GI
	DIV_FLOAT_VAR_BY_FLOAT_VAR	0071		GF	GF
	DIV_INT_LVAR_BY_INT_LVAR	0072		LI	LI
	DIV_FLOAT_LVAR_BY_FLOAT_LVAR	0073		LF	LF
	DIV_INT_VAR_BY_INT_LVAR	0074		GI	LI
	DIV_FLOAT_VAR_BY_FLOAT_LVAR	0075		GF	LF
	DIV_INT_LVAR_BY_INT_VAR	0076		LI	GI
	DIV_FLOAT_LVAR_BY_FLOAT_VAR	0077		LF	GF
+=@	ADD_TIMED_VAL_TO_FLOAT_VAR	0078	2	GF	VF
	ADD_TIMED_VAL_TO_FLOAT_LVAR	0079		LF	VF
	ADD_TIMED_FLOAT_VAR_TO_FLOAT_VAR	007A		GF	GF
	ADD_TIMED_FLOAT_LVAR_TO_FLOAT_LVAR	007B		LF	LF
	ADD_TIMED_FLOAT_LVAR_TO_FLOAT_VAR	007C		LF	GF
	ADD_TIMED_FLOAT_VAR_TO_FLOAT_LVAR	007D		GF	LF
-=@	SUB_TIMED_VAL_FROM_FLOAT_VAR	007E	2	GF	VF
	SUB_TIMED_VAL_FROM_FLOAT_LVAR	007F		LF	VF
	SUB_TIMED_FLOAT_VAR_FROM_FLOAT_VAR	0080		GF	GF
	SUB_TIMED_FLOAT_LVAR_FROM_FLOAT_LVAR	0081		LF	LF
	SUB_TIMED_FLOAT_LVAR_FROM_FLOAT_VAR	0082		LF	GF
	SUB_TIMED_FLOAT_VAR_FROM_FLOAT_LVAR	0083		GF	LF
=	SET_VAR_INT_TO_VAR_INT	0084	2	GI	GI
	SET_LVAR_INT_TO_LVAR_INT	0085		LI	LI
	SET_VAR_FLOAT_TO_VAR_FLOAT	0086		GF	GF
	SET_LVAR_FLOAT_TO_LVAR_FLOAT	0087		LF	LF
	SET_VAR_FLOAT_TO_LVAR_FLOAT	0088		GF	LF
	SET_LVAR_FLOAT_TO_VAR_FLOAT	0089		LF	GF
	SET_VAR_INT_TO_LVAR_INT	008A		GI	LI
	SET_LVAR_INT_TO_VAR_INT	008B		LI	GI
=#	CSET_VAR_INT_TO_VAR_FLOAT	008C	2	GI	GF
	CSET_VAR_FLOAT_TO_VAR_INT	008D		GF	GI
	CSET_LVAR_INT_TO_VAR_FLOAT	008E		LI	GF
	CSET_LVAR_FLOAT_TO_VAR_INT	008F		LF	GI
	CSET_VAR_INT_TO_LVAR_FLOAT	0090		GI	LF
	CSET_VAR_FLOAT_TO_LVAR_INT	0091		GF	LI
	CSET_LVAR_INT_TO_LVAR_FLOAT	0092		LI	LF
	CSET_LVAR_FLOAT_TO_LVAR_INT	0093		LF	LI
ABS	ABS_VAR_INT	0094	1	GI
	ABS_LVAR_INT	0095		LI
	ABS_VAR_FLOAT	0096		GF
	ABS_LVAR_FLOAT	0097		LF
ANDOR[*]		00D6	1	VI
LAUNCH_MISSION		00D7	1	VR
PLAYER_MADE_PROGRESS		030C	1	VI
SET_PROGRESS_TOTAL		030D	1	VI
REGISTER_MISSION_GIVEN		0317	0
REGISTER_MISSION_PASSED		0318	1	VT
SCRIPT_NAME		03A4	1	VT
LOAD_AND_LAUNCH_MISSION		0416	1	VR
LOAD_AND_LAUNCH_MISSION_INTERNAL		0417	1	VI
SET_TOTAL_NUMBER_OF_MISSIONS		042C	1	VI
REGISTER_ODDJOB_MISSION_PASSED		0595	0
CREATE_COLLECTABLE1		02EC	1	VI
SET_COLLECTABLE1_TOTAL		02ED	1	VI
GOTO_IF_TRUE[*]		004C	1	VR
=	IS_INT_VAR_EQUAL_TO_CONSTANT	04A3	2	GC	VC
	IS_INT_LVAR_EQUAL_TO_CONSTANT	04A4		LC	VC
	SET_VAR_INT_TO_CONSTANT	04AE		GC	VC
	SET_LVAR_INT_TO_CONSTANT	04AF		LC	VC
>	IS_INT_VAR_GREATER_THAN_CONSTANT	04B0	2	GC	VC
	IS_INT_LVAR_GREATER_THAN_CONSTANT	04B1		LC	VC
	IS_CONSTANT_GREATER_THAN_INT_VAR	04B2		VC	GC
	IS_CONSTANT_GREATER_THAN_INT_LVAR	04B3		VC	LC
>=	IS_INT_VAR_GREATER_OR_EQUAL_TO_CONSTANT	04B4	2	GC	VC
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_CONSTANT	04B5		LC	VC
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT_VAR	04B6		VC	GV
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT_LVAR	04B7		VC	LC
LOAD_AND_LAUNCH_MISSION_EXCLUSIVE		0515	1	VR
GOSUB_FILE		02CD	2	VR	VR
=	SET_ANY_TEXT_LABEL_TO_VAR_TEXT_LABEL[*]	05A9	2	GT	VT
				GT	GT
				GT	LT
	SET_ANY_TEXT_LABEL_TO_LVAR_TEXT_LABEL[*]	05AA		LT	VT
				LT	GT
				LT	LT
	IS_TEXT_LABEL_VAR_EQUAL_TO_TEXT_LABEL_ANY[*]	05AD		GT	VT
				GT	GT
				GT	LT
	IS_TEXT_LABEL_LVAR_EQUAL_TO_TEXT_LABEL_ANY[*]	05AE		LT	VT
				LT	GT
				LT	LT
	SET_ANY_STRING_TO_VAR_STRING[*]	06D1		GS	VS
				GS	GS
				GS	LS
	SET_ANY_STRING_TO_LVAR_STRING[*]	06D2		LS	VS
				LS	GS
				LS	LS
	IS_INT_LVAR_EQUAL_TO_INT_VAR	07D6		LI	GI
	IS_FLOAT_LVAR_EQUAL_TO_FLOAT_VAR	07D7		LF	GF
IS_TEXT_LABEL_NULL[*]	IS_TEXT_LABEL_NULL_VAR_TEXT_LABEL[*]	0844	1	GT
	IS_TEXT_LABEL_NULL_LVAR_TEXT_LABEL[*]	0845		LT
IS_STRING_NULL[*]	IS_STRING_NULL_VAR_STRING[*]	0846	1	GS
	IS_STRING_NULL_LVAR_STRING[*]	0847		LS
INIT_TABLE_OF_GOTO[*][*]		0871	18	GI	VI	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR
				LI	VI	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR
APPEND_GOTO_TO_TABLE[*][*]		0872	18	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR	VI	VR
IS_BIT_SET	IS_BIT_SET_VAR_INT_NUMBER[*]	08B4	2	GI	VN
	IS_BIT_SET_VAR_INT_VAR_INT[*]	08B5		GI	GI
	IS_BIT_SET_VAR_INT_LVAR_INT[*]	08B6		GI	LI
	IS_BIT_SET_LVAR_INT_NUMBER[*]	08B7		LI	VN
	IS_BIT_SET_LVAR_INT_VAR_INT[*]	08B8		LI	GI
	IS_BIT_SET_LVAR_INT_LVAR_INT[*]	08B9		LI	LI
SET_BIT_SET	SET_BIT_VAR_INT_NUMBER[*]	08BA	2	GI	VN
	SET_BIT_VAR_INT_VAR_INT[*]	08BB		GI	GI
	SET_BIT_VAR_INT_LVAR_INT[*]	08BC		GI	LI
	SET_BIT_LVAR_INT_NUMBER[*]	08BD		LI	VN
	SET_BIT_LVAR_INT_VAR_INT[*]	08BE		LI	GI
	SET_BIT_LVAR_INT_LVAR_INT[*]	08BF		LI	LI
CLEAR_BIT_SET	CLEAR_BIT_VAR_INT_NUMBER[*]	08C0	2	GI	VN
	CLEAR_BIT_VAR_INT_VAR_INT[*]	08C1		GI	GI
	CLEAR_BIT_VAR_INT_LVAR_INT[*]	08C2		GI	LI
	CLEAR_BIT_LVAR_INT_NUMBER[*]	08C3		LI	VN
	CLEAR_BIT_LVAR_INT_VAR_INT[*]	08C4		LI	GI
	CLEAR_BIT_LVAR_INT_LVAR_INT[*]	08C5		LI	LI
= COMPARE_STRING[*]	IS_STRING_VAR_EQUAL_TO_STRING_ANY[*] COMPARE_STRING_VAR_STRING_ANY_STRING[*]	08F9	2	GS	VS
				GS	GS
				GS	LS
	IS_STRING_LVAR_EQUAL_TO_STRING_ANY[*] COMPARE_STRING_LVAR_STRING_ANY_STRING[*]	08FA		LS	VS
				LS	GS
				LS	LS
RETURN_TRUE		00C5	0
RETURN_FALSE		00C6	0
ANDOR[*]		00DB	1	VI
LAUNCH_MISSION		00DC	1	VR
GOSUB_FILE		02D2	2	VR	VR
PLAYER_MADE_PROGRESS		0311	1	VI
SET_PROGRESS_TOTAL		0312	1	VI
REGISTER_MISSION_GIVEN		031C	0
REGISTER_MISSION_PASSED		031D	1	VT
SCRIPT_NAME		03A9	1	VT
LOAD_AND_LAUNCH_MISSION		041B	1	VR
LOAD_AND_LAUNCH_MISSION_INTERNAL		041C	1	VI
SET_TOTAL_NUMBER_OF_MISSIONS		0431	1	VI
REGISTER_ODDJOB_MISSION_PASSED		059A	0
=	IS_INT_VAR_EQUAL_TO_CONSTANT	04A8	2	GC	VC
	IS_INT_LVAR_EQUAL_TO_CONSTANT	04A9		LC	VC
	SET_VAR_INT_TO_CONSTANT	04B3		GC	VC
	SET_LVAR_INT_TO_CONSTANT	04B4		LC	VC
>	IS_INT_VAR_GREATER_THAN_CONSTANT	04B5	2	GC	VC
	IS_INT_LVAR_GREATER_THAN_CONSTANT	04B6		LC	VC
	IS_CONSTANT_GREATER_THAN_INT_VAR	04B7		VC	GC
	IS_CONSTANT_GREATER_THAN_INT_LVAR	04B8		VC	LC
>=	IS_INT_VAR_GREATER_OR_EQUAL_TO_CONSTANT	04B9	2	GC	VC
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_CONSTANT	04BA		LC	VC
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT_VAR	04BB		VC	GV
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT_LVAR	04BC		VC	LC
CALL[*][*][*]		05AE	1	VR	_ _ _
CALLB[*][*][*]		05AF	1	VR	_ _ _
=	SET_ANY_INT	0004	2	GI	VI
				LI	VI
	SET_ANY_FLOAT	0005		GF	VF
				LF	VF
	SET_ANY_TEXT_LABEL	0006		GT	VT
				LT	VT
+=	ADD_VAL_TO_INT_ANY	0007	2	GI	VI
				LI	VI
	ADD_VAL_TO_FLOAT_ANY	0008		GF	VF
				LF	VF
-=	SUB_VAL_FROM_INT_ANY	0009	2	GI	VI
				LI	VI
	SUB_VAL_FROM_FLOAT_ANY	000A		GF	VF
				LF	VF
*=	MULT_INT_ANY_BY_VAL	000B	2	GI	VI
				LI	VI
	MULT_FLOAT_ANY_BY_VAL	000C		GF	VF
				LF	VF
/=	DIV_INT_ANY_BY_VAL	000D	2	GI	VI
				LI	VI
	DIV_FLOAT_ANY_BY_VAL	000E		GF	VF
				LF	VF
>	IS_INT_ANY_GREATER_THAN_NUMBER	000F	2	GI	VN
				LI	VN
	IS_NUMBER_GREATER_THAN_INT_ANY	0010		VN	GI
				VN	LI
	IS_INT_ANY_GREATER_THAN_INT_ANY	0011		GI	GI
				GI	LI
				LI	GI
				LI	LI
	IS_FLOAT_ANY_GREATER_THAN_NUMBER	0012		GF	VN
				LF	VN
	IS_NUMBER_GREATER_THAN_FLOAT_ANY	0013		VN	GF
				VN	LF
	IS_FLOAT_ANY_GREATER_THAN_FLOAT_ANY	0014		GF	GF
				GF	LF
				LF	GF
				LF	LF
>=	IS_INT_ANY_GREATER_OR_EQUAL_TO_NUMBER	0015	2	GI	VN
				LI	VN
	IS_NUMBER_GREATER_OR_EQUAL_TO_INT_ANY	0016		VN	GI
				VN	LI
	IS_INT_ANY_GREATER_OR_EQUAL_TO_INT_ANY	0017		GI	GI
				GI	LI
				LI	GI
				LI	LI
	IS_FLOAT_ANY_GREATER_OR_EQUAL_TO_NUMBER	0018		GF	VN
				LF	VN
	IS_NUMBER_GREATER_OR_EQUAL_TO_FLOAT_ANY	0019		VN	GF
				VN	LF
	IS_FLOAT_ANY_GREATER_OR_EQUAL_TO_FLOAT_ANY	001A		GF	GF
				GF	LF
				LF	GF
				LF	LF
=	IS_INT_ANY_EQUAL_TO_NUMBER	001B	2	GI	VN
				LI	VN
	IS_INT_ANY_EQUAL_TO_INT_ANY	001C		GI	GI
				GI	LI
				LI	GI
				LI	LI
	IS_FLOAT_ANY_EQUAL_TO_NUMBER	001D		GF	VN
				LF	VN
	IS_FLOAT_ANY_EQUAL_TO_FLOAT_ANY	001E		GF	GF
				GF	LF
				LF	GF
				LF	LF
=	IS_TEXT_LABEL_ANY_EQUAL_TO_TEXT_LABEL	001F	2	GT	VT
				LT	VT
	IS_ANY_TEXT_LABEL_EQUAL_TO_TEXT_LABEL_ANY	0020		GT	GT
				GT	LT
				LT	GT
				LT	LT
GOTO_IF_TRUE[*]		0021	1	VR
GOTO_IF_FALSE[*]		0022	1	VR
TERMINATE_THIS_SCRIPT		0023	0
MISSION_END
START_NEW_SCRIPT[*]		0024	1	VR	_ _ _
GOSUB		0025	1	VR
RETURN		0026	0
+=	ADD_INT_ANY_TO_INT_ANY	0029	2	GI	GI
				GI	LI
				LI	GI
				LI	LI
	ADD_FLOAT_ANY_FLOAT_ANY	002A		GF	GF
				GF	LF
				LF	GF
				LF	LF
-=	SUB_INT_ANY_FROM_INT_ANY	002B	2	GI	GI
				GI	LI
				LI	GI
				LI	LI
	SUB_FLOAT_ANY_FROM_FLOAT_ANY	002C		GF	GF
				GF	LF
				LF	GF
				LF	LF
*=	MULT_INT_ANY_BY_INT_ANY	002D	2	GI	GI
				GI	LI
				LI	GI
				LI	LI
	MULT_FLOAT_ANY_BY_FLOAT_ANY	002E		GF	GF
				GF	LF
				LF	GF
				LF	LF
/=	DIV_INT_ANY_BY_INT_ANY	002F	2	GI	GI
				GI	LI
				LI	GI
				LI	LI
	DIV_FLOAT_ANY_BY_FLOAT_ANY	0030		GF	GF
				GF	LF
				LF	GF
				LF	LF
+=@	ADD_TIMED_VAL_TO_FLOAT_ANY	0031	2	GF	VF
				LF	VF
	ADD_TIMED_FLOAT_ANY_TO_FLOAT_ANY	0032		GF	GF
				GF	LF
				LF	GF
				LF	LF
-=@	SUB_TIMED_VAL_FROM_FLOAT_ANY	0033	2	GF	VF
				LF	VF
	SUB_TIMED_FLOAT_ANY_FROM_FLOAT_ANY	0034		GF	GF
				GF	LF
				LF	GF
				LF	LF
=	SET_ANY_INT_TO_ANY_INT	0035	2	GI	GI
				GI	LI
				LI	GI
				LI	LI
	SET_ANY_FLOAT_TO_ANY_FLOAT	0036		GF	GF
				GF	LF
				LF	GF
				LF	LF
	SET_ANY_TEXT_LABEL_TO_ANY_TEXT_LABEL	0037		GT	GT
				GT	LT
				LT	GT
				LT	LT
=#	CSET_ANY_INT_TO_ANY_FLOAT	0038	2	GI	GF
				GI	LF
				LI	GF
				LI	LF
	CSET_ANY_FLOAT_TO_ANY_INT	0039		GF	GI
				GF	LI
				LF	GI
				LF	LI
ABS	ABS_ANY_INT	003A	1	GI
				LI
	ABS_ANY_FLOAT	003B		GF
				LF
RETURN_TRUE		005E	0
RETURN_FALSE		005F	0
ANDOR[*]		0078	1	VI
LAUNCH_MISSION		0079	1	VR
GOSUB_FILE		01BA	2	VR	VR
PLAYER_MADE_PROGRESS		01DF	1	VI
SET_PROGRESS_TOTAL		01E0	1	VI
REGISTER_MISSION_GIVEN		01EA	0
REGISTER_MISSION_PASSED		01EB	1	VT
SCRIPT_NAME		0238	1	VT
LOAD_AND_LAUNCH_MISSION		0288	1	VR
LOAD_AND_LAUNCH_MISSION_INTERNAL		0289	1	VI
SET_TOTAL_NUMBER_OF_MISSIONS		0296	1	VI
=	IS_INT_ANY_EQUAL_TO_CONSTANT	02DB	2	GC	VC
				LC	VC
	SET_ANY_INT_TO_CONSTANT	02E2		GC	VC
				LC	VC
>	IS_INT_ANY_GREATER_THAN_CONSTANT	02E3	2	GC	VC
				LC	VC
	IS_CONSTANT_GREATER_THAN_INT_ANY	02E4		VC	GC
				VC	LC
>=	IS_INT_ANY_GREATER_OR_EQUAL_TO_CONSTANT	02E5	2	GC	VC
				LC	VC
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT_ANY	02E6		VC	GV
				VC	LC
REGISTER_ODDJOB_MISSION_PASSED		036A	0
CALL[*][*][*]		037A	1	VR	_ _ _
CALLB[*][*][*]		037B	1	VR	_ _ _
SET_COLLECTABLE2_TOTAL		04DA	1	VI

Notes

^ A special mission directive which is never compiled.

^ It is used also to build statements internally.

^ It has an undefined amount of arguments.

^ It is a likely definition of the standard command.

^ Arguments amount varies when compiling.

This section is incomplete. You can help by fixing and expanding it.

Uncommons

Arguments of some commands keep uncommon values which look familiar after encoding:

Command	Arg. ID	Syntax	Encoded
			Command	Arg. ID	Value	Type
GOTO	1	Any label	GOTO	1	Offset	INT
GOTO_IF_FALSE	1	Any label	GOTO_IF_FALSE	1	Offset	INT
GOSUB	1	Gosub label	GOSUB	1	Offset	INT
GOSUB_FILE	1	Gosub label	GOSUB_FILE	1	0-based offset	INT
	2	Foreign gosub file		2
	1	Gosub label		1	Negative offset
	2	Foreign gosub label		2
START_NEW_SCRIPT	1	Script label	START_NEW_SCRIPT	1	0-based offset	INT
LAUNCH_MISSION	1	Subscript file	LAUNCH_MISSION	1	0-based offset	INT
		Subscript label			Negative offset
LOAD_AND_LAUNCH_MISSION	1	Mission script file	LOAD_AND_LAUNCH_MISSION_INTERNAL	1	Mission identifier	INT
		Mission script label	LOAD_AND_LAUNCH_MISSION		Negative offset
GOTO_IF_TRUE	1	Any label	GOTO_IF_TRUE	1	Offset	INT
LOAD_AND_LAUNCH_MISSION_EXCLUSIVE	1	Mission script file	LOAD_AND_LAUNCH_MISSION_INTERNAL	1	Negative mission identifier	INT
		Mission script label	LOAD_AND_LAUNCH_MISSION		Negative offset
CALL CALLB	1	Function label	CALL CALLB	1	Function arguments	INT
				2	Returning arguments
				3	Parent script locals
				4	Offset

This section is incomplete. You can help by fixing and expanding it.

Comparing rule

The comparing rule can handle up to 8 checks per construct. 006D (, , ), 00DB () and 0078 () indicate you are verifying a single check (0) or multiple checks with either AND (1 to 8) or OR (21 to 28) logical operators (see also ANDOR).

Analysis

As an overview of the compiled source, statements are literally nested meaning that the code is unoptimized. Furthermore, the jump of an embedded construct doesn't get merged with that of the construct itself, which consists of a benefit for the code parsing.

IF

As regards the IF statement, if the whole check is true the consequence is performed and the code jumps to the end of the construct, otherwise it skips to the alternative (see also Comparing rule):

Decompiled				Compiled
IF [NOT] {condition0} [AND|OR [NOT] {condition8}] {consequence} [ELSE {alternative}] ENDIF	{006D} {....} {....} {004D} {....} {0002} ---- {....} ----	{00DB} {....} {....} {004D} {....} {0002} ---- {....} ----	{0078} {....} {....} {0022} {....} {0002} ---- {....} ----	ANDOR {value} [NOT] {condition0} [[NOT] {condition8}] GOTO_IF_FALSE ELSE {consequence} [GOTO ENDIF] ELSE: [{alternative} ENDIF:]

IFNOT

Not that much to say more than the preceding construct, the IFNOT statement is built nearly in the same way. In fact, the ELSE clause points to the alternative, whereas the GOTO jumps to its end. The substantial difference consists in the substitution of GOTO_IF_FALSE with GOTO_IF_TRUE:

Decompiled				Compiled
IFNOT [NOT] {condition0} [AND|OR [NOT] {condition8}] {consequence} [ELSE {alternative}] ENDIF	{00D6} {....} {....} {004C} {....} {0002} ---- {....} ----	{00DB} {....} {....} {004C} {....} {0002} ---- {....} ----	{0078} {....} {....} {0021} {....} {0002} ---- {....} ----	ANDOR {value} [NOT] {condition0} [[NOT] {condition8}] GOTO_IF_TRUE ELSE {consequence} [GOTO ENDIF] ELSE: [{alternative} ENDIF:]

WHILE

The WHILE statement is pretty much similar to the previous, even though when the consequence is read the code is moved to the beginning of the construct:

Decompiled				Compiled
WHILE [NOT] {condition0} [AND|OR [NOT] {condition8}] {consequence} ENDWHILE	---- {006D} {....} {....} {004D} {....} {0002} ----	---- {00DB} {....} {....} {004D} {....} {0002} ----	---- {0078} {....} {....} {0022} {....} {0002} ----	WHILE: ANDOR {value} [NOT] {condition0} [[NOT] {condition8}] GOTO_IF_FALSE ENDWHILE {consequence} GOTO WHILE ENDWHILE:

WHILENOT

To say the least, WHILENOT statement follows the same constitution of both WHILE and IFNOT constructs, by exchanging GOTO_IF_FALSE with GOTO_IF_TRUE:

Decompiled				Compiled
WHILENOT [NOT] {condition0} [AND|OR [NOT] {condition8}] {consequence} ENDWHILE	---- {00D6} {....} {....} {004C} {....} {0002} ----	---- {00DB} {....} {....} {004C} {....} {0002} ----	---- {0078} {....} {....} {0021} {....} {0002} ----	WHILENOT: ANDOR {value} [NOT] {condition0} [[NOT] {condition8}] GOTO_IF_TRUE ENDWHILE {consequence} GOTO WHILENOT ENDWHILE:

REPEAT

Seemingly, the REPEAT statement is the first construct ever optimized as a result of a possible R* compiler fault. Moreover, it sounds ambiguous as it loops at least once. This was probably the intention of R* programmers, that is iterating at least once else the construct is useless. However, there are few chance they decide to use such structure to avoid some conflict with some other constructs:

Decompiled	G/L		G/L	Compiled
REPEAT {times} {varname} {consequence} ENDREPEAT	{0004} ---- {....} {0008} {0028} {004D}	{0005} ---- {....} {0009} {0029} {004D}	{0004} ---- {....} {0007} {0015} {0022}	{varname} = {value0} LOOP: {consequence} ++ {varname} {varname} >= {valueN} GOTO_IF_FALSE LOOP

CASE

In , the CASE statement is more complex and efficient because the game uses internally a binary search algorithm to jump at the label that matches with the value of a particular case. This method requires a known amount of cases which is up to 75. When a case is true, a consequence is executed and the code jumps to the end of the construct, otherwise the alternative may be performed. As the code is unoptimized, the GOTO of the last case is still compiled even though its label points to the end of the jump itself:

Decompiled		Compiled
CASE {varname} WHEN {value0} {consequence} [WHEN {valueN} {consequence}] [ELSE {alternative}] ENDCASE	{0871} {0872} ---- {....} {0002} ---- {....} {0002} ---- {....} {0002} ----	{varname} {cases} {iselse} ELSE {value0} WHEN0 {valueN} WHENN -1 ENDCASE -1 ENDCASE -1 ENDCASE -1 ENDCASE -1 ENDCASE [-1 ENDCASE -1 ENDCASE -1 ENDCASE -1 ENDCASE -1 ENDCASE -1 ENDCASE -1 ENDCASE -1 ENDCASE -1 ENDCASE] WHEN0: {consequence} GOTO ENDCASE [WHENN: {consequence} GOTO ENDCASE] [ELSE: {alternative} GOTO ENDCASE] ENDCASE:

In and , such statement is a set of nested IF constructs which causes a very slight loss of performance by considering that 00DB () and 0078 ( aren't compiled:

Decompiled	G/L		G/L	Compiled
CASE {varname} WHEN {value0} {consequence} [WHEN {valueN} {consequence}] [ELSE {alternative}] ENDCASE	---- {0038} {004D} {....} {0002} ---- {0038} {004D} {....} {0002} ---- {....} ---- ----	---- {0039} {004D} {....} {0002} ---- {0039} {004D} {....} {0002} ---- {....} ---- ----	---- {001B} {0022} {....} {0002} ---- {001B} {0022} {....} {0002} ---- {....} ---- ----	WHEN0: {varname} = {value0} GOTO_IF_FALSE WHENN {consequence} [GOTO ENDCASE0] WHENN: [{varname} = {valueN} GOTO_IF_FALSE ELSE {consequence} [GOTO ENDCASEN] ELSE: [{alternative} ENDCASEN:]] ENDCASE0:

Optimization

In and , whenever a single condition is checked 00DB () and 0078 () don't get compiled cause no logical operator (AND, OR) is used and so they become really useless. Its lack increase the script efficiency a lot. However, the jump of the ELSE clause of an IF statement which points to the end of the construct is still compiled after a GOTO. Furthermore, Stories Games come with an improved data type managing which causes a considerable decrease of the compiled file size.

Tools

• SCRambl - an open-source tool provided by Deji

External links

• DMA's official GTA2script Compiler V9.6, DMA's official GTA2script information
• GTAIII 10th Anniversary source
• GTA VC definitions - some sort of information by Wesser as a result of the reverse-engineering applied to the Rockstar Games' official GTA3 Script Compiler V413
• GTA3 Script Compiler on gtamodding.ru (also includes download)