SCM language

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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 GTA2script. The ancient documentation by DMA (at present Rockstar North), mentions GTA2script as a successor to GBHscript - a language used in GTA 1 (GBH was a planned name for GTA). Therefore, the language used in GTA 3 series should've been called GTA3script. It was influenced by both BASIC and C programming languages.

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

Comments are notes left in the code to aid readability or to explain a part of code that may be confusing otherwise. Comments are ignored by the compiler. R*'s compiler supports C++ style comments – single-line comments and multiline comments.

A single line comment only affects a single line. They are prefixed with // (two slashes). Anything between these slashes and the end of the line is a comment. Single line comments may appear at the end of a line of code as well as on their own line.

[...] // This comment is at the end of a line.

// This comment is on its own line.

Multiline comments appear between /* and */. They do not actually have to span multiple lines, and anything outside of the opening and closing tokens is not ignored (i.e. these comments may appear with code on either side on the same line).

[...]
/*
  This comment spans
  multiple lines.
*/
[...]

[...] /* This comment is within a line */ [...] /* As is this one */ [...]

R*'s compiler allows multiline comments to be nested.

Highlighters

Highlighters behaviour sounds trivial, that's to say they simply highlight one or more arguments per command within round brackets, individually or together. 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

Limits

Opening and closing round brakets are treated as blank spaces;

An optional comma can be used as well to distinguish each argument, processed as a space.

Scopes

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

{
    [...]
}

Limits

Scopes cannot be nested;

Opening and closing curly brakets are real commands.

Labels

A label is a sequence of characters which identify the reference of a location of the source code useful for gotoes. 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 memory address that is given a name. Variables are used to reference values that are stored in the game's memory and that can change (hence the name "variable"). Instructions may read the variable's memory or write to it. They act in the same way as pointers in other programming languages.

There are several words related to variables that are important to know:

• The value of the variable is the data that lies at the variable's memory address.
• The type is what kind of value the variable stores.
• The scope is the region of code in which the variable may be used (and in which it is declared). There are two types:
  • The global scope is shared between all game scripts. Global variables have the same value everywhere. They are declared with the VAR prefix.
  • The local scope is a region of code within a script. Locals are only visible to other code inside the same pair of curly braces. They are declared with the LVAR prefix.
• A timer is a unique local variable whose value rises automatically. They start counting when the script starts executing, and continue counting indefinitely. There are two such timers, TIMERA and TIMERB which are always defined, so do not need to be declared.

Data types

---

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

For an in-depth description of different data types, see the SCM instruction page.

LABEL

The LABEL type handles variable-length strings. It can refer to either a label name or a file name.

Notes

While inside a script file, R* compiler treats it unambiguously as a label;

R* compiler allocates 32 bytes per label.

Limit

LABEL variables aren't available.

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 6-7 digits beyond which it may get lost.

Notes

R* compiler also accepts f and F suffixes for the immediate value.

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. Literal only TEXT_LABEL* strings are probably marked by single quotation marks to distinguish them from variable and constant identifiers:

PRINT_BIG 'GXT_KEY'

Limit

TEXT_LABEL variables are supported in and .

TEXT_LABEL16

The TEXT_LABEL16 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.

Limit

TEXT_LABEL16 variables and values are supported only in .

TEXT_LABEL32

The TEXT_LABEL32 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 TEXT_LABEL32 argument may begin. Strings of such type must be put within double quotation marks:

SAVE_STRING_TO_DEBUG_FILE "32B-128B TEXT"

Limits

TEXT_LABEL32 values are supported since ;

TEXT_LABEL32 variables aren't available.

TEXT

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

Limits

TEXT values are supported since ;

TEXT variables aren't available.

CONST (pseudo)

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

Limit

The assignment and comparison of CONST values are supported since .

MULTI (pseudo)

The MULTI type handles a group of few data types acceptable per argument. It is used only for commands featuring optional arguments, those whose type is unpredictable before the compilation. It can be a pseudo type of INT, FLOAT and TEXT_LABEL.

Notes

INT and FLOAT can be used interchangeably in , , , and ;

also admits TEXT_LABEL arguments.

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:

VAR_* {varname0}[,] [... {varnameN}]
LVAR_* {varname0}[,] [... {varnameN}]

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

{
    VAR_* {varname0}[,] [... {varnameN}]
    LVAR_* {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.

Limits

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 TEXT_LABEL16 types occupy respectively 2 and 4 variables to store their data (have a look here for further details);

isn't affected by what said above;

Global and local variable names must not collide.

Arrays

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

{
    VAR_* {varname0}{[arrsize0]}[,] [... {varnameN}{[arrsizeN]}]
    LVAR_* {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 ;

The aforesaid indices are one-based, possibly zero-based since ;

Multidimensional arrays are not supported.

Handles

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

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

Note

R* compiler won't let you assign different entity types to the same variable or using a variable which hasn't been passed to any command designated to the creation of an entity.

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, CONST, TEXT_LABEL and TEXT_LABEL16 types are free from these operators, except for the basic assignment (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

Note

^ As a result of a critical bug, R* compiler mistakenly applies the operator inversion.

Commands

A command is a symbolic name associated to an identifier which executes a portion of code that specifies the operation to be performed by passing zero or more arguments. An argument is in turn some data given as input to a command. Normally, commands have a defined amount of arguments and those not, such as START_NEW_SCRIPT, can pass as many arguments as the available local variables are, except timers. Being a procedure, a command does not return values that can be assigned to a variable, even though the boolean flag is kept whenever it is used as a condition. It follows the common programming syntax adopted for function calls:

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

Alternators

An alternator is an operation that is implemented with a set of commands rather than a single command, with a specific implementation being chosen by the compiler based on the data types used in the operation. For example, the game sees adding an integer to an integer as a different operation to adding an integer to a float, so there are multiple commands that add values together that differ only in parameter types.

Each command in a set has the same arity as the other commands in the set. The only difference is the combination and order of the parameter types.

The following commands are all alternators:

•    :
  • 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_EMPTY
  • IS_BIT_SET
  • SET_BIT
  • CLEAR_BIT
  • STRING_CAT

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

Hardcoded

Hardcoded commands are those which have unique characteristics and are handled internally:

•    :
  • GOTO
  • GOTO_IF_FALSE
  • TERMINATE_THIS_SCRIPT
  • START_NEW_SCRIPT
  • VAR_INT
  • VAR_FLOAT
  • LVAR_INT
  • LVAR_FLOAT
  • {
  • }
  • REPEAT
  • ENDREPEAT
  • IF
  • IFNOT
  • ELSE
  • ENDIF
  • WHILE
  • WHILENOT
  • ENDWHILE
  • ANDOR
  • LAUNCH_MISSION
  • SAVE_VAR_INT
  • SAVE_VAR_FLOAT
  • START_CUTSCENE^[*]
  • 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^[*]
  • VAR_TEXT_LABEL
  • LVAR_TEXT_LABEL
• :
  • REGISTER_ODDJOB_MISSION_PASSED
• :
  • GOTO_IF_TRUE
  • GOSUB_FILE
• :
  • CREATE_COLLECTABLE1
  • SET_COLLECTABLE1_TOTAL^[*]
• :
  • LOAD_AND_LAUNCH_MISSION_EXCLUSIVE
• :
  • CALL
  • CALLNOT
• :
  • VAR_TEXT_LABEL16
  • LVAR_TEXT_LABEL16
  • SWITCH
  • ENDSWITCH
  • CASE
  • DEFAULT
  • BREAK
  • SWITCH_START
  • SWITCH_CONTINUED
• :
  • SAVE_VAR_TEXT_LABEL^[*]
  • SET_COLLECTABLE2_TOTAL

Notes

^ 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 don'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 what expected, a 0-value must be passed;

^ This command was intended to be counted originally but its counter got deprecated.

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

WAIT

WAIT stops 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 may or may not break after more than one frame, such as the WHILE control flow. In this case, a INT equal to 0 is passed.

GOTO

GOTO jumps to the label of any location of the source code but conceptually it should never point off the current context. It is also used internally to build the control flows offered by the scripting language:

// File: any.sc

goto_ref0:
GOTO goto_refN

// File: any.sc

goto_refN:
GOTO goto_ref0

ANDOR

ANDOR sets out the way the comparison among more conditions have to occur (see also Compare flag).

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 desired label only if the comparison returns false.

SCRIPT_NAME

SCRIPT_NAME simply associates an unique name to the current working script.

Note

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

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. Since , these are the seemingly predetermined bytes of a random empty string block which are actually the result of uninitialized data:

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

The split of such bytes into 4 blocks of 32-bytes each is quite noticeable.

Constants

A constant is a symbolic name associated to a specific value. When compiling, their caption is converted to the assigned value. 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 CONST type accept only constant values of a single namespace.

Notes

Constants don't collide even though they belong to different namespaces;

In and , they are hardcoded as everything inside R* compiler;

In , the subdivision of constant namespaces in files might be just a listing of hardcoded constants useful for developers. The same would apply to and .

Formatting

Everything is case-insensitive, that means the uppercase and lowercase letters have no dissimilarities when taken. Usually, the source code is conform to the same formatting according to:

• Labels and variables are entirely in lowercase;
• Declarations, commands and control flows are in uppercase;
• Constants are mostly in uppercase but the lowercase variant can be seen as well.
  
  

Compiling

Structure

The source code is split up into several SC files which comprehend main file, foreign gosubs, subscripts, mission scripts, and streamed 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:

<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

Note

R* compiler will scan subfolders too.

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 as well:

// File: main.sc

GOSUB_FILE gosub_ref foreign_gosub.sc

// File: foreign_gosub.sc

gosub_ref:
{
    [...]
}
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 gosub_ref

// File: any.sc

gosub_ref:
{
    [...]
}
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_* {varname0}[,] [... {varnameN}]]

SCRIPT_NAME main

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

    [...]
}
//GOTO subscript_loop
MISSION_END

Notes

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;

MISSION_END is an alias of TERMINATE_THIS_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_* {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_* {varname0}[,] [... {varnameN}]]

mission_start:

REGISTER_MISSION_GIVEN
SCRIPT_NAME mission

// Variables initialization

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

    [...]
}
GOTO mission_passed

mission_failed:
[...]
RETURN

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

// Mark everything as no longer needed

mission_cleanup:
//MISSION_HAS_FINISHED
[...]
RETURN

Some missions doesn't need to be executed multiple times because they may just initialize some global variables defined in the main script or launch the intro mission. For this matter, here comes the usage of LOAD_AND_LAUNCH_MISSION_EXCLUSIVE:

// File: main.sc

LOAD_AND_LAUNCH_MISSION_EXCLUSIVE initial.sc
LOAD_AND_LAUNCH_MISSION_EXCLUSIVE intro.sc

Note

Exclusive missions are never launched in the source code. It's likely, it was an idea not came to the end successfully or rather they were useful for debugging purposes.

Limits

LOAD_AND_LAUNCH_MISSION_EXCLUSIVE is available only in and ;

Only 2 exclusive missions in and 3 in are handled, plus they must be launched before any of the counterpart.

Streamed scripts

---

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

Control flow

As usual, the evolution of something implies its development over the years. Alongside, the control flows 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 the most common conditional statement. It executes one block of code if a boolean condition is true, and (optionally) another if the condition is false. The condition may be made of multiple conditions combined using the logical operators AND or OR, or it may just be a single condition. AND makes the final condition true only if all of the input conditions are true, whereas OR only requires one input condition to be true. The condition may be inverted with NOT, another logical operator. Syntax:

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

Limitations

• There is a maximum of 8 conditions.

If-not

IFNOT works in the same way as IF except that the condition is always inverted.

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

Limitations

• IFNOT is only supported in games that have GOTO_IF_TRUE: , and .

While

WHILE is similar to IF, but it continues executing the body until the condition is false.

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

While-not

WHILENOT is to WHILE as IFNOT is to IF: it loops until the condition is true.

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

Limitations

• Like IFNOT, WHILENOT is only supported in games that have GOTO_IF_TRUE: , and .

Repeat

REPEAT acts as a range-based loop (generally a for-loop in modern programming languages). It executes the body and increments a certain variable until it reaches a target value, at which point the loop stops.

REPEAT {target} {varname}
    {consequence}
ENDREPEAT

Limitations

• REPEAT is supported in games from ;
• The target value must be positive;
• The body will be read at least once in any case.

Switch

A SWITCH statement is functionally equivalent to multiple nested IF...ELSE statements. It takes a single value and executes a block of code that is specific to that value (a CASE) until it finds a BREAK, which moves execution to the end of the construct. If no matching case is found, the DEFAULT clause is executed.

SWITCH {varname}
    CASE {value0}
        {consequence}
        BREAK
    [CASE {valueN}
        {consequence}
        BREAK]
    [DEFAULT
        {alternative}
        BREAK]
ENDSWITCH

Limitations

• It is supported from ;
• CASE allows the use of INT and CONST values only;
• In , the CASE values should be sorted (R*'s compiler should do it implicitly);
• Every CASE, including DEFAULT, must end with a BREAK.

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. Streamed 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 streamed scripts respect the same rule except the fact they are turned into a zero-based growing identifier, while exclusive mission scripts are launched by a negative identifier resulting from the bits inversion (bitwise complement).

Offsets

An offset is a 32-bit signed integer which points to a location of the script file. 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 streamed scripts are relative and negative offsets starting from their beginning. The offset is related to global variables as well, whose interval goes from 8 and ends to 65532 (0xFFFC), each one is aligned to the nearest 4 bytes.

Variables range

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
Streamed 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	t0-t1	t0-t1

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

Command ID

A command ID is a 16-bit signed integer internal and progressive identifier, somehow referred to as part of the hexadecimal representation of an opcode, which identifies the command to execute at runtime, forming the game's script bytecode. The maximum number of available commands is 32767 (0x7FFF), since the least significant bit (0x8000) is set whenever they are used as negative conditions (those with the NOT logical operator, just to clear things up).

Command arguments

The limitation of the amount of arguments a variadic command can pass is game specific:

• 16 for and ;
• 32 for ;
• 96 for and .

Managed commands

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

Legend:

• Prefix:
  • V, VAR;
  • L, LVAR;
  • A, ANY (VALUE, VAR, LVAR).

• Specifier:
  • R, LABEL;
  • I, INT;
  • F, FLOAT;
  • T, TEXT_LABEL;
  • T16, TEXT_LABEL16;
  • T32, TEXT_LABEL32;
  • T[N], TEXT;
  • C, CONST;
  • M, MULTI.

• Suffix:
  • O, OPTIONAL.

List:

Be aware, the argument data types of the commands below are just informative:

Command		ID	Arguments
			#	1	2	3	4	...	18	...	n+l
											n+i+o
MISSION_START[*]			0
GOTO[*]		2	1	R
= SET	SET_VAR_INT	4	2	VI	I
	SET_VAR_FLOAT	5		VF	F
	SET_LVAR_INT	6		LI	I
	SET_LVAR_FLOAT	7		LF	F
	SET_VAR_INT_TO_VAR_INT	132		VI	VI
	SET_LVAR_INT_TO_LVAR_INT	133		LI	LI
	SET_VAR_FLOAT_TO_VAR_FLOAT	134		VF	VF
	SET_LVAR_FLOAT_TO_LVAR_FLOAT	135		LF	LF
	SET_VAR_FLOAT_TO_LVAR_FLOAT	136		VF	LF
	SET_LVAR_FLOAT_TO_VAR_FLOAT	137		LF	VF
	SET_VAR_INT_TO_LVAR_INT	138		VI	LI
	SET_LVAR_INT_TO_VAR_INT	139		LI	VI
+= + ADD_THING_TO_THING	ADD_VAL_TO_INT_VAR	8	2	VI	I
	ADD_VAL_TO_FLOAT_VAR	9		VF	F
	ADD_VAL_TO_INT_LVAR	10		LI	I
	ADD_VAL_TO_FLOAT_LVAR	11		LF	F
	ADD_INT_VAR_TO_INT_VAR	88		VI	VI
	ADD_FLOAT_VAR_TO_FLOAT_VAR	89		VF	VF
	ADD_INT_LVAR_TO_INT_LVAR	90		LI	LI
	ADD_FLOAT_LVAR_TO_FLOAT_LVAR	91		LF	LF
	ADD_INT_VAR_TO_INT_LVAR	92		LI	VI
	ADD_FLOAT_VAR_TO_FLOAT_LVAR	93		LF	VF
	ADD_INT_LVAR_TO_INT_VAR	94		VI	LI
	ADD_FLOAT_LVAR_TO_FLOAT_VAR	95		VF	LF
-= - SUB_THING_FROM_THING	SUB_VAL_FROM_INT_VAR	12	2	VI	I
	SUB_VAL_FROM_FLOAT_VAR	13		VF	F
	SUB_VAL_FROM_INT_LVAR	14		LI	I
	SUB_VAL_FROM_FLOAT_LVAR	15		LF	F
	SUB_INT_VAR_FROM_INT_VAR	96		VI	VI
	SUB_FLOAT_VAR_FROM_FLOAT_VAR	97		VF	VF
	SUB_INT_LVAR_FROM_INT_LVAR	98		LI	LI
	SUB_FLOAT_LVAR_FROM_FLOAT_LVAR	99		LF	LF
	SUB_INT_VAR_FROM_INT_LVAR	100		LI	VI
	SUB_FLOAT_VAR_FROM_FLOAT_LVAR	101		LF	VF
	SUB_INT_LVAR_FROM_INT_VAR	102		VI	LI
	SUB_FLOAT_LVAR_FROM_FLOAT_VAR	103		VF	LF
*= * MULT_THING_BY_THING	MULT_INT_VAR_BY_VAL	16	2	VI	I
	MULT_FLOAT_VAR_BY_VAL	17		VF	F
	MULT_INT_LVAR_BY_VAL	18		LI	I
	MULT_FLOAT_LVAR_BY_VAL	19		LF	F
	MULT_INT_VAR_BY_INT_VAR	104		VI	VI
	MULT_FLOAT_VAR_BY_FLOAT_VAR	105		VF	VF
	MULT_INT_LVAR_BY_INT_LVAR	106		LI	LI
	MULT_FLOAT_LVAR_BY_FLOAT_LVAR	107		LF	LF
	MULT_INT_VAR_BY_INT_LVAR	108		VI	LI
	MULT_FLOAT_VAR_BY_FLOAT_LVAR	109		VF	LF
	MULT_INT_LVAR_BY_INT_VAR	110		LI	VI
	MULT_FLOAT_LVAR_BY_FLOAT_VAR	111		LF	VF
/= / DIV_THING_BY_THING	DIV_INT_BY_VAL	20	2	VI	I
	DIV_FLOAT_VAR_BY_VAL	21		VF	F
	DIV_INT_LVAR_BY_VAL	22		LI	I
	DIV_FLOAT_LVAR_BY_VAL	23		LF	F
	DIV_INT_VAR_BY_INT_VAR	112		VI	VI
	DIV_FLOAT_VAR_BY_FLOAT_VAR	113		VF	VF
	DIV_INT_LVAR_BY_INT_LVAR	114		LI	LI
	DIV_FLOAT_LVAR_BY_FLOAT_LVAR	115		LF	LF
	DIV_INT_VAR_BY_INT_LVAR	116		VI	LI
	DIV_FLOAT_VAR_BY_FLOAT_LVAR	117		VF	LF
	DIV_INT_LVAR_BY_INT_VAR	118		LI	VI
	DIV_FLOAT_LVAR_BY_FLOAT_VAR	119		LF	VF
> <= IS_THING_GREATER_THAN_THING	IS_INT_VAR_GREATER_THAN_NUMBER	24	2	VI	I
	IS_INT_LVAR_GREATER_THAN_NUMBER	25		LI	I
	IS_NUMBER_GREATER_THAN_INT_VAR	26		I	VI
	IS_NUMBER_GREATER_THAN_INT_LVAR	27		I	LI
	IS_INT_VAR_GREATER_THAN_INT_VAR	28		VI	VI
	IS_INT_LVAR_GREATER_THAN_INT_LVAR	29		LI	LI
	IS_INT_VAR_GREATER_THAN_INT_LVAR	30		VI	LI
	IS_INT_LVAR_GREATER_THAN_INT_VAR	31		LI	VI
	IS_FLOAT_VAR_GREATER_THAN_NUMBER	32		VF	F
	IS_FLOAT_LVAR_GREATER_THAN_NUMBER	33		LF	F
	IS_NUMBER_GREATER_THAN_FLOAT_VAR	34		F	VF
	IS_NUMBER_GREATER_THAN_FLOAT_LVAR	35		F	LF
	IS_FLOAT_VAR_GREATER_THAN_FLOAT_VAR	36		VF	VF
	IS_FLOAT_LVAR_GREATER_THAN_FLOAT_LVAR	37		LF	LF
	IS_FLOAT_VAR_GREATER_THAN_FLOAT_LVAR	38		VF	LF
	IS_FLOAT_LVAR_GREATER_THAN_FLOAT_VAR	39		LF	VF
>= < IS_THING_GREATER_OR_EQUAL_TO_THING	IS_INT_VAR_GREATER_OR_EQUAL_TO_NUMBER	40	2	VI	I
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_NUMBER	41		LI	I
	IS_NUMBER_GREATER_OR_EQUAL_TO_INT_VAR	42		I	VI
	IS_NUMBER_GREATER_OR_EQUAL_TO_INT_LVAR	43		I	LI
	IS_INT_VAR_GREATER_OR_EQUAL_TO_INT_VAR	44		VI	VI
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_INT_LVAR	45		LI	LI
	IS_INT_VAR_GREATER_OR_EQUAL_TO_INT_LVAR	46		VI	LI
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_INT_VAR	47		LI	VI
	IS_FLOAT_VAR_GREATER_OR_EQUAL_TO_NUMBER	48		VF	F
	IS_FLOAT_LVAR_GREATER_OR_EQUAL_TO_NUMBER	49		LF	F
	IS_NUMBER_GREATER_OR_EQUAL_TO_FLOAT_VAR	50		F	VF
	IS_NUMBER_GREATER_OR_EQUAL_TO_FLOAT_LVAR	51		F	LF
	IS_FLOAT_VAR_GREATER_OR_EQUAL_TO_FLOAT_VAR	52		VF	VF
	IS_FLOAT_LVAR_GREATER_OR_EQUAL_TO_FLOAT_LVAR	53		LF	LF
	IS_FLOAT_VAR_GREATER_OR_EQUAL_TO_FLOAT_LVAR	54		VF	LF
	IS_FLOAT_LVAR_GREATER_OR_EQUAL_TO_FLOAT_VAR	55		LF	VF
= IS_THING_EQUAL_TO_THING	IS_INT_VAR_EQUAL_TO_NUMBER	56	2	VI	I
	IS_INT_LVAR_EQUAL_TO_NUMBER	57		LI	I
	IS_INT_VAR_EQUAL_TO_INT_VAR	58		VI	VI
	IS_INT_LVAR_EQUAL_TO_INT_LVAR	59		LI	LI
	IS_INT_VAR_EQUAL_TO_INT_LVAR	60		VI	LI
	IS_FLOAT_VAR_EQUAL_TO_NUMBER	66		VF	F
	IS_FLOAT_LVAR_EQUAL_TO_NUMBER	67		LF	F
	IS_FLOAT_VAR_EQUAL_TO_FLOAT_VAR	68		VF	VF
	IS_FLOAT_LVAR_EQUAL_TO_FLOAT_LVAR	69		LF	LF
	IS_FLOAT_VAR_EQUAL_TO_FLOAT_LVAR	70		VF	LF
NOT = IS_THING_NOT_EQUAL_TO_THING	IS_INT_VAR_NOT_EQUAL_TO_NUMBER	61	2	VI	I
	IS_INT_LVAR_NOT_EQUAL_TO_NUMBER	62		LI	I
	IS_INT_VAR_NOT_EQUAL_TO_INT_VAR	63		VI	VI
	IS_INT_LVAR_NOT_EQUAL_TO_INT_LVAR	64		LI	LI
	IS_INT_VAR_NOT_EQUAL_TO_INT_LVAR	65		VI	LI
	IS_FLOAT_VAR_NOT_EQUAL_TO_NUMBER	71		VF	F
	IS_FLOAT_LVAR_NOT_EQUAL_TO_NUMBER	72		LF	F
	IS_FLOAT_VAR_NOT_EQUAL_TO_FLOAT_VAR	73		VF	VF
	IS_FLOAT_LVAR_NOT_EQUAL_TO_FLOAT_LVAR	74		LF	LF
	IS_FLOAT_VAR_NOT_EQUAL_TO_FLOAT_LVAR	75		VF	LF
GOTO_IF_FALSE[*]		77	1	R
TERMINATE_THIS_SCRIPT		78	0
MISSION_END
START_NEW_SCRIPT[*]		79	1+l	R	AM
GOSUB		80	1	R
RETURN		81	0
+=@ +@ ADD_THING_TO_THING_TIMED	ADD_TIMED_VAL_TO_FLOAT_VAR	120	2	VF	F
	ADD_TIMED_VAL_TO_FLOAT_LVAR	121		LF	F
	ADD_TIMED_FLOAT_VAR_TO_FLOAT_VAR	122		VF	VF
	ADD_TIMED_FLOAT_LVAR_TO_FLOAT_LVAR	123		LF	LF
	ADD_TIMED_FLOAT_LVAR_TO_FLOAT_VAR	124		LF	VF
	ADD_TIMED_FLOAT_VAR_TO_FLOAT_LVAR	125		VF	LF
-=@ -@ SUB_THING_FROM_THING_TIMED	SUB_TIMED_VAL_FROM_FLOAT_VAR	126	2	VF	F
	SUB_TIMED_VAL_FROM_FLOAT_LVAR	127		LF	F
	SUB_TIMED_FLOAT_VAR_FROM_FLOAT_VAR	128		VF	VF
	SUB_TIMED_FLOAT_LVAR_FROM_FLOAT_LVAR	129		LF	LF
	SUB_TIMED_FLOAT_LVAR_FROM_FLOAT_VAR	130		LF	VF
	SUB_TIMED_FLOAT_VAR_FROM_FLOAT_LVAR	131		VF	LF
=# CSET	CSET_VAR_INT_TO_VAR_FLOAT	140	2	VI	VF
	CSET_VAR_FLOAT_TO_VAR_INT	141		VF	VI
	CSET_LVAR_INT_TO_VAR_FLOAT	142		LI	VF
	CSET_LVAR_FLOAT_TO_VAR_INT	143		LF	VI
	CSET_VAR_INT_TO_LVAR_FLOAT	144		VI	LF
	CSET_VAR_FLOAT_TO_LVAR_INT	145		VF	LI
	CSET_LVAR_INT_TO_LVAR_FLOAT	146		LI	LF
	CSET_LVAR_FLOAT_TO_LVAR_INT	147		LF	LI
ABS	ABS_VAR_INT	148	1	VI
	ABS_LVAR_INT	149		LI
	ABS_VAR_FLOAT	150		VF
	ABS_LVAR_FLOAT	151		LF
VAR_INT[*]		199	n	VI	VIO
VAR_FLOAT[*]		200	n	VF	VFO
LVAR_INT[*]		201	n	LI	LIO
LVAR_FLOAT[*]		202	n	LF	LFO
{[*]		203	0
}[*]		204	0
IF[*]		207	1	I
ELSE[*]		209	0
ENDIF[*]		210	0
WHILE[*]		211	1	I
ENDWHILE[*]		213	0
ANDOR[*]		214	1	I
LAUNCH_MISSION		215	1	R
START_CUTSCENE		743	0
PLAYER_MADE_PROGRESS		780	1	I
SET_PROGRESS_TOTAL		781	1	I
REGISTER_MISSION_GIVEN		791	0
REGISTER_MISSION_PASSED		792	1	T
SCRIPT_NAME		932	1	T
LOAD_AND_LAUNCH_MISSION		1046	1	R
LOAD_AND_LAUNCH_MISSION_INTERNAL		1047	1	I
SET_TOTAL_NUMBER_OF_MISSIONS		1068	1	I
REGISTER_ODDJOB_MISSION_PASSED		1429	0
REPEAT[*]		205	2	I	VLI
ENDREPEAT[*]		206	0
CREATE_COLLECTABLE1		748	1	I
SET_COLLECTABLE1_TOTAL		749	1	I
GOTO_IF_TRUE[*]		76	1	R
= IS_THING_EQUAL_TO_THING	IS_INT_VAR_EQUAL_TO_CONSTANT	1187	2	VI	C
	IS_INT_LVAR_EQUAL_TO_CONSTANT	1188		LI	C
= SET	SET_VAR_INT_TO_CONSTANT	1198	2	VI	C
	SET_LVAR_INT_TO_CONSTANT	1199		LI	C
> <= IS_THING_GREATER_THAN_THING	IS_INT_VAR_GREATER_THAN_CONSTANT	1200	2	VI	C
	IS_INT_LVAR_GREATER_THAN_CONSTANT	1201		LI	C
	IS_CONSTANT_GREATER_THAN_INT_VAR	1202		C	VI
	IS_CONSTANT_GREATER_THAN_INT_LVAR	1203		C	LI
>= < IS_THING_GREATER_OR_EQUAL_TO_THING	IS_INT_VAR_GREATER_OR_EQUAL_TO_CONSTANT	1204	2	VI	C
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_CONSTANT	1205		LI	C
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT_VAR	1206		C	VI
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT_LVAR	1207		C	LI
LOAD_AND_LAUNCH_MISSION_EXCLUSIVE		1301	1	R
IFNOT[*]		208	1	I
WHILENOT[*]		212	1	I
GOSUB_FILE		717	2	R	R
= SET	SET_VAR_TEXT_LABEL	1449	2	VT	AT
	SET_LVAR_TEXT_LABEL	1450		LT	AT
VAR_TEXT_LABEL[*]		1451	n	VT	VTO
LVAR_TEXT_LABEL[*]		1452	n	LT	LTO
= IS_THING_EQUAL_TO_THING	IS_VAR_TEXT_LABEL_EQUAL_TO_TEXT_LABEL	1453	2	VT	AT
	IS_LVAR_TEXT_LABEL_EQUAL_TO_TEXT_LABEL	1454		LT	AT
= SET	SET_VAR_TEXT_LABEL16	1745	2	VT16	AT16
	SET_LVAR_TEXT_LABEL16	1476		LT16	AT16
VAR_TEXT_LABEL16[*]		1477	n	VT16	VT16O
LVAR_TEXT_LABEL16[*]		1478	n	LT16	LT16O
= IS_THING_EQUAL_TO_THING	IS_INT_LVAR_EQUAL_TO_INT_VAR	2006	2	LI	VI
	IS_FLOAT_LVAR_EQUAL_TO_FLOAT_VAR	2007		LF	VF
IS_EMPTY[*]	IS_VAR_TEXT_LABEL_EMPTY	2116	1	VT
	IS_LVAR_TEXT_LABEL_EMPTY	2117		LT
	IS_VAR_TEXT_LABEL16_EMPTY	2118		VT16
	IS_LVAR_TEXT_LABEL16_EMPTY	2119		LT16
SWITCH[*]		2120	1	VLI
ENDSWITCH[*]		2121	0
CASE[*]		2122	1	I
DEFAULT[*]		2123	0
BREAK[*]		2124	0
SWITCH_START[*]		2161	18	VI	I	I	R	I
								R
				LI	I	I	R	I
								R
SWITCH_CONTINUED[*]		2162	18	I
				R
IS_BIT_SET[*]	IS_GLOBAL_VAR_BIT_SET_CONST	2228	2	VI	C
	IS_GLOBAL_VAR_BIT_SET_VAR	2229		VI	VI
	IS_GLOBAL_VAR_BIT_SET_LVAR	2230		VI	LI
	IS_LOCAL_VAR_BIT_SET_CONST	2231		LI	C
	IS_LOCAL_VAR_BIT_SET_VAR	2232		LI	VI
	IS_LOCAL_VAR_BIT_SET_LVAR	2233		LI	LI
SET_BIT[*]	SET_GLOBAL_VAR_BIT_CONST	2234	2	VI	C
	SET_GLOBAL_VAR_BIT_VAR	2235		VI	VI
	SET_GLOBAL_VAR_BIT_LVAR	2236		VI	LI
	SET_LOCAL_VAR_BIT_CONST	2237		LI	C
	SET_LOCAL_VAR_BIT_VAR	2238		LI	VI
	SET_LOCAL_VAR_BIT_LVAR	2239		LI	LI
CLEAR_BIT[*]	CLEAR_GLOBAL_VAR_BIT_CONST	2240	2	VI	C
	CLEAR_GLOBAL_VAR_BIT_VAR	2241		VI	VI
	CLEAR_GLOBAL_VAR_BIT_LVAR	2242		VI	LI
	CLEAR_LOCAL_VAR_BIT_CONST	2243		LI	C
	CLEAR_LOCAL_VAR_BIT_VAR	2244		LI	VI
	CLEAR_LOCAL_VAR_BIT_LVAR	2245		LI	LI
= IS_THING_EQUAL_TO_THING	IS_VAR_TEXT_LABEL16_EQUAL_TO_TEXT_LABEL	2297	2	VT16	AT16
	IS_LVAR_TEXT_LABEL16_EQUAL_TO_TEXT_LABEL	2298		LT16	AT16
STRING_CAT[*]	STRING_CAT16	2443	3	VT16	VT16	VT16
	STRING_CAT8	2444		VT	VT	VT
RETURN_TRUE		197	0
RETURN_FALSE		198	0
SWITCH[*][*]		214	1	VLI
ENDSWITCH[*][*]		215	0
CASE[*][*]		216	1	I
DEFAULT[*][*]		217	0
BREAK[*][*]		218	0
ANDOR[*]		219	1	I
LAUNCH_MISSION		220	1	R
SAVE_VAR_INT[*]		502	l	VI	VIO
SAVE_VAR_FLOAT[*]		503	l	VF	VFO
GOSUB_FILE		722	2	R	R
START_CUTSCENE		748	0
PLAYER_MADE_PROGRESS		785	1	I
SET_PROGRESS_TOTAL		786	1	I
REGISTER_MISSION_GIVEN		796	0
REGISTER_MISSION_PASSED		797	1	T
SCRIPT_NAME		937	1	T
LOAD_AND_LAUNCH_MISSION		1051	1	R
LOAD_AND_LAUNCH_MISSION_INTERNAL		1052	1	I
SET_TOTAL_NUMBER_OF_MISSIONS		1073	1	I
= IS_THING_EQUAL_TO_THING	IS_INT_VAR_EQUAL_TO_CONSTANT	1192	2	VI	C
	IS_INT_LVAR_EQUAL_TO_CONSTANT	1193		LI	C
= SET	SET_VAR_INT_TO_CONSTANT	1203	2	VI	C
	SET_LVAR_INT_TO_CONSTANT	1204		LI	C
> <= IS_THING_GREATER_THAN_THING	IS_INT_VAR_GREATER_THAN_CONSTANT	1205	2	VI	C
	IS_INT_LVAR_GREATER_THAN_CONSTANT	1206		LI	C
	IS_CONSTANT_GREATER_THAN_INT_VAR	1207		C	VI
	IS_CONSTANT_GREATER_THAN_INT_LVAR	1208		C	LI
>= < IS_THING_GREATER_OR_EQUAL_TO_THING	IS_INT_VAR_GREATER_OR_EQUAL_TO_CONSTANT	1209	2	VI	C
	IS_INT_LVAR_GREATER_OR_EQUAL_TO_CONSTANT	1210		LI	C
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT_VAR	1211		C	VI
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT_LVAR	1212		C	LI
REGISTER_ODDJOB_MISSION_PASSED		1434	0
CALL[*][*][*]		1454	1+i+o	R	AM
					VLM
CALLNOT[*][*][*]		1455	1+i+o	R	AM
					VLM
= SET	SET_INT[*]	4	2	VLI	I
	SET_FLOAT[*]	5		VLF	F
	SET_TEXT_LABEL[*]	6		VLT	T
	SET_INT_TO_INT[*]	53		VLI	VLI
	SET_FLOAT_TO_FLOAT[*]	54		VLF	VLF
	SET_TEXT_LABEL_TO_TEXT_LABEL[*]	55		VLT	VLT
	SET_INT_TO_CONSTANT[*]	738		VLI	C
+= + ADD_THING_TO_THING	ADD_VAL_TO_INT[*]	7	2	VLI	I
	ADD_VAL_TO_FLOAT[*]	8		VLF	F
	ADD_INT_TO_INT[*]	41		VLI	VLI
	ADD_FLOAT_TO_FLOAT[*]	42		VLF	VLF
-= - SUB_THING_FROM_THING	SUB_VAL_FROM_INT[*]	9	2	VLI	I
	SUB_VAL_FROM_FLOAT[*]	10		VLF	F
	SUB_INT_FROM_INT[*]	43		VLI	VLI
	SUB_FLOAT_FROM_FLOAT[*]	44		VLF	VLF
*= * MULT_THING_BY_THING	MULT_INT_BY_VAL[*]	11	2	VLI	I
	MULT_FLOAT_BY_VAL[*]	12		VLF	F
	MULT_INT_BY_INT[*]	45		VLI	VLI
	MULT_FLOAT_BY_FLOAT[*]	46		VLF	VLF
/= / DIV_THING_BY_THING	DIV_INT_BY_VAL[*]	13	2	VLI	I
	DIV_FLOAT_BY_VAL[*]	14		VLF	F
	DIV_INT_BY_INT[*]	47		VLI	VLI
	DIV_FLOAT_BY_FLOAT[*]	48		VLF	VLF
> <= IS_THING_GREATER_THAN_THING	IS_INT_GREATER_THAN_NUMBER[*]	15	2	VLI	I
	IS_NUMBER_GREATER_THAN_INT[*]	16		I	VLI
	IS_INT_GREATER_THAN_INT[*]	17		VLI	VLI
	IS_FLOAT_GREATER_THAN_NUMBER[*]	18		VLF	F
	IS_NUMBER_GREATER_THAN_FLOAT[*]	19		F	VLF
	IS_FLOAT_GREATER_THAN_FLOAT[*]	20		VLF	VLF
	IS_INT_GREATER_THAN_CONSTANT[*]	739		VLI	C
	IS_CONSTANT_GREATER_THAN_INT[*]	740		C	VLI
>= < IS_THING_GREATER_OR_EQUAL_TO_THING	IS_INT_GREATER_OR_EQUAL_TO_NUMBER[*]	21	2	VLI	I
	IS_NUMBER_GREATER_OR_EQUAL_TO_INT[*]	22		I	VLI
	IS_INT_GREATER_OR_EQUAL_TO_INT[*]	23		VLI	VLI
	IS_FLOAT_GREATER_OR_EQUAL_TO_NUMBER[*]	24		VLF	F
	IS_NUMBER_GREATER_OR_EQUAL_TO_FLOAT[*]	25		F	VLF
	IS_FLOAT_GREATER_OR_EQUAL_TO_FLOAT[*]	26		VLF	VLF
	IS_INT_GREATER_OR_EQUAL_TO_CONSTANT[*]	741		VLI	C
	IS_CONSTANT_GREATER_OR_EQUAL_TO_INT[*]	742		C	VLI
= IS_THING_EQUAL_TO_THING	IS_INT_EQUAL_TO_NUMBER[*]	27	2	VLI	I
	IS_INT_EQUAL_TO_INT[*]	28		VLI	VLI
	IS_FLOAT_EQUAL_TO_NUMBER[*]	29		VLF	F
	IS_FLOAT_EQUAL_TO_FLOAT[*]	30		VLF	VLF
	IS_TEXT_LABEL_EQUAL_TO_STRING[*]	31		VLT	T
	IS_TEXT_LABEL_EQUAL_TO_TEXT_LABEL[*]	32		VLT	VLT
	IS_INT_EQUAL_TO_CONSTANT[*]	731		VLI	C
GOTO_IF_TRUE[*]		33	1	R
GOTO_IF_FALSE[*]		34	1	R
TERMINATE_THIS_SCRIPT		35	0
MISSION_END
START_NEW_SCRIPT[*]		36	1+l	R	AM
GOSUB		37	1	R
RETURN		38	0
+=@ +@ ADD_THING_TO_THING_TIMED	ADD_TIMED_VAL_TO_FLOAT[*]	49	2	VLF	F
	ADD_TIMED_FLOAT_TO_FLOAT[*]	50		VLF	VLF
-=@ -@ SUB_THING_FROM_THING_TIMED	SUB_TIMED_VAL_FROM_FLOAT[*]	51	2	VLF	F
	SUB_TIMED_FLOAT_FROM_FLOAT[*]	52		VLF	VLF
=# CSET	CSET_INT_TO_FLOAT[*]	56	2	VLI	VLF
	CSET_FLOAT_TO_INT[*]	57		VLF	VLI
ABS	ABS_INT[*]	58	1	VLI
	ABS_FLOAT[*]	59		VLF
RETURN_TRUE		94	0
RETURN_FALSE		95	0
VAR_INT[*][*]		96	n	VI	VIO
VAR_FLOAT[*][*]		97	n	VF	VFO
LVAR_INT[*][*]		98	n	LI	LIO
LVAR_FLOAT[*][*]		99	n	LF	LFO
VAR_TEXT_LABEL[*][*]		100	n	VT	VTO
LVAR_TEXT_LABEL[*][*]		101	n	LT	LTO
{[*][*]		102	0
}[*][*]		103	0
IF[*][*]		104	1	I
IFNOT[*][*]		105	1	I
ELSE[*][*]		106	0
ENDIF[*][*]		107	0
WHILE[*][*]		108	1	I
WHILENOT[*][*]		109	1	I
ENDWHILE[*][*]		110	0
REPEAT[*][*]		111	2	I	VLI
ENDREPEAT[*][*]		112	0
SWITCH[*][*]		113	1	VLI
ENDSWITCH[*][*]		114	0
CASE[*][*]		115	1	I
DEFAULT[*][*]		116	0
BREAK[*][*]		117	0
ANDOR[*]		120	1	I
LAUNCH_MISSION		121	1	R
SAVE_VAR_INT[*]		297	l	VI	VIO
SAVE_VAR_FLOAT[*]		298	l	VF	VFO
SAVE_VAR_TEXT_LABEL[*]		299	l	VT	VTO
GOSUB_FILE		442	2	R	R
PLAYER_MADE_PROGRESS		479	1	I
SET_PROGRESS_TOTAL		480	1	I
REGISTER_MISSION_GIVEN		490	0
REGISTER_MISSION_PASSED		491	1	T
SCRIPT_NAME		568	1	T
LOAD_AND_LAUNCH_MISSION		648	1	R
LOAD_AND_LAUNCH_MISSION_INTERNAL		649	1	I
SET_TOTAL_NUMBER_OF_MISSIONS		662	1	I
REGISTER_ODDJOB_MISSION_PASSED		874	0
CALL[*][*][*]		890	1+i+o	R	AM
					VLM
CALLNOT[*][*][*]		891	1+i+o	R	AM
					VLM
SET_COLLECTABLE2_TOTAL		1242	1	I

Notes

^ A special mission directive which is never compiled;

^ It is used to build the various control flows internally;

^ It is used to declare one or more variables;

^ It embeds a variable scope;

^ It has an undefined amount of arguments;

^ It is a likely definition of the standard command;

^ It should exist but its position is purely guessed;

^ Arguments amount varies when compiling.

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

Uncommon values

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

Command	Arg. ID	Value	Encoded
			Command	Arg. ID	Value	Type
GOTO	1	Generic label	GOTO	1	Positive/Negative offset	INT
GOTO_IF_FALSE	1	Generic label	GOTO_IF_FALSE	1	Positive/Negative offset	INT
GOSUB	1	Gosub label	GOSUB	1	Positive/Negative offset	INT
GOSUB_FILE	1	Gosub label	GOSUB_FILE	1	Zero-based offset	INT
	2	Foreign gosub file		2
	1	Gosub label		1	Positive/Negative offset
	2	Foreign gosub label		2
START_NEW_SCRIPT	1	Script label	START_NEW_SCRIPT	1	Positive/Negative offset	INT
	l	Passed locals		l	Passed locals	ANY_MULTI
LAUNCH_MISSION	1	Subscript file	LAUNCH_MISSION	1	Zero-based offset	INT
		Subscript label			Positive/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		Positive/Negative offset
GOTO_IF_TRUE	1	Generic label	GOTO_IF_TRUE	1	Positive/Negative 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_EXCLUSIVE		Positive/Negative offset
CALL CALLNOT	1	Function label	CALL CALLNOT	1	# of input arguments	INT
				2	# of output arguments
				3	# of script locals
				4	Positive/Negative offset
	i	Input arguments		i	Input arguments	ANY_MULTI
	o	Output arguments		o	Output arguments	HOLD_MULTI

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

Compare flag

The compare flag is an internal script-dependent flag which makes conditional GOTOs such as GOTO_IF_TRUE (unavailable in   ) and GOTO_IF_FALSE deciding whether to jump otherwise. It can handle up to 8 checks per conditional statement and indicates you are verifying a single condition (0, see also Optimization) or multiple conditions with either AND (1 to 8) or OR (21 to 28) logical operators (see also ANDOR).

Control flows analysis

As an overview of the compiled source, control flows 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 control flow, 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 Compare flag):

Decompiled				Compiled
IF [NOT] {condition0} [AND|OR [NOT] {condition8}] {consequence} [ELSE {alternative}] ENDIF	{..214} {.....} {.....} {...77} {.....} {....2} ----- {.....} -----	{..219} {.....} {.....} {...77} {.....} {....2} ----- {.....} -----	{..120} {.....} {.....} {...34} {.....} {....2} ----- {.....} -----	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 control flow 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	{..214} {.....} {.....} {...76} {.....} {....2} ----- {.....} -----	{..219} {.....} {.....} {...76} {.....} {....2} ----- {.....} -----	{..120} {.....} {.....} {...33} {.....} {....2} ----- {.....} -----	ANDOR {value} [NOT] {condition0} [[NOT] {condition8}] GOTO_IF_TRUE ELSE {consequence} [GOTO ENDIF] ELSE: [{alternative} ENDIF:]

WHILE

The WHILE control flow is built pretty much similarly 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	----- {..214} {.....} {.....} {...77} {.....} {....2} -----	----- {..219} {.....} {.....} {...77} {.....} {....2} -----	----- {..120} {.....} {.....} {...34} {.....} {....2} -----	WHILE: ANDOR {value} [NOT] {condition0} [[NOT] {condition8}] GOTO_IF_FALSE ENDWHILE {consequence} GOTO WHILE ENDWHILE:

WHILENOT

To say the least, WHILENOT control flow 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	----- {..214} {.....} {.....} {...76} {.....} {....2} -----	----- {..219} {.....} {.....} {...76} {.....} {....2} -----	----- {..120} {.....} {.....} {...33} {.....} {....2} -----	WHILENOT: ANDOR {value} [NOT] {condition0} [[NOT] {condition8}] GOTO_IF_TRUE ENDWHILE {consequence} GOTO WHILENOT ENDWHILE:

REPEAT

Seemingly, the REPEAT control flow 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	{....4} ----- {.....} {....8} {...40} {...77}	{....5} ----- {.....} {....9} {...41} {...77}	{....4} ----- {.....} {....7} {...21} {...34}	{varname} = {value0} LOOP: {consequence} ++ {varname} {varname} >= {valueN} GOTO_IF_FALSE LOOP

SWITCH

In , the SWITCH control flow 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 right after the command mentioned earlier:

Decompiled		Compiled
SWITCH {varname} CASE {value0} {consequence} BREAK [CASE {valueN} {consequence} BREAK] [DEFAULT {alternative} BREAK] ENDSWITCH	{.2161} {.2162} ----- {.....} {....2} ----- {.....} {....2} ----- {.....} {....2} -----	SWITCH_START {varname} {numcases} {isdefault} DEFAULT {value0} CASE0 ... [SWITCH_CONTINUED ... {valueN} CASEN [-1 ENDSWITCH]] CASE0: {consequence} GOTO ENDSWITCH [CASEN: {consequence} GOTO ENDSWITCH] [DEFAULT: {alternative} GOTO ENDSWITCH] ENDSWITCH:

In and , such control flow is a set of nested IF constructs which causes a very slight loss of performance by considering that ANDOR isn't compiled:

Decompiled	G/L		G/L	Compiled
SWITCH {varname} CASE {value0} {consequence} BREAK] [CASE {valueN} {consequence} BREAK] [DEFAULT {alternative} BREAK] ENDSWITCH	----- {...56} {...77} {.....} {....2} ----- {...56} {...77} {.....} {....2} ----- {.....} ----- -----	----- {...57} {...77} {.....} {....2} ----- {...57} {...77} {.....} {....2} ----- {.....} ----- -----	----- {...27} {...34} {.....} {....2} ----- {...27} {...34} {.....} {....2} ----- {.....} ----- -----	CASE0: {varname} = {value0} GOTO_IF_FALSE CASEN {consequence} GOTO ENDSWITCH0 CASEN: [{varname} = {valueN} GOTO_IF_FALSE DEFAULT {consequence} GOTO ENDSWITCHN DEFAULT: [{alternative} ENDSWITCHN:]] ENDSWITCH0:

Optimization

In and , whenever a single condition is checked ANDOR doesn't get compiled cause no logical operator (AND, OR) is used and so they become really useless. Its lack increases 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
• Mission Scripting Tools

See also

• SCM language III/VC definitions

External links

• DMA's official GTA2script Compiler V9.6, DMA's official GTA2script information - found into the game copy
• GTA III 10th Anniversary source - found into the iOS game copy
• GTA III unofficial main.sc - Reconstruction of main.sc, missing from the iOS source code, by Link2012
• GTA III/VC unavailable script commands (possibly NOP'd) - some sort of information by Wesser as a result of the reverse-engineering applied to the Rockstar Games' official GTA3 Script Compiler V413
• Official GTA3 Script Compiler V413 - found into the GTA VC 10th Anniversary copy
• GTA3 Script Compiler V413 Compilation Strings - a list by Wesser of all the error messages the compiler can throw and more
• GTA SA PC/PS2/XBOX script commands, GTA SA Mobile script commands - taken directly from the Android application and rearranged by Wesser
•  GTAForums: Reconstructing the III .sc language – a post by NTAuthority