FANDOM


Overall FormatEdit

(02 00 01)h + 32 bit int     Jump to second segment

byte                         Target game (0x6C for III, 0x6D for VC, 0x73 for SA)

(Global vars)              Space for variable saving

(02 00 01)h + 32 bit int     Jump to third segment

byte                         Padding (always 0)

32 bit int                 Number of models

(model names)              24 byte model names * number of models (model 0 name is empty and therefore unused)

(02 00 01)h + 32 bit int     Jump to fourth segment

byte                         Padding (always 0)

32 bit int                 MAIN size

32 bit int                 Largest mission size

32 bit int                 Number of missions

(mission addresses)        32 bit addresses * number of missions

(MAIN code)                  MAIN section, equal to size defined earlier

(mission code)               The mission data, missions stored at offsets defined earlier

Main SectionEdit

Made up of many opcodes one after the other. Opcodes are of the format:



TOpcode {

Opcode[2]: Word; //Opocode number in word format

Parameters: Array Of TParameter;

}



The number of parameters is specific for each opcode. The opcode database has all of the opcodes in VC, with their parameter numbers, and for most, a description of what they do. Parameters are of the format:



TParameter {

ParameterType[1]: Byte; //Says which type of parameter will follow

ActualParameter: varies; //The actual parameter

}



The parameter types are as follows (but there are more in SA):



Labels use the type 01 (although if they address is small enough using data types 04 and 05 will also work). Global and local vars can also be used for labels. Global vars reference a position in the file much like a label. There is a space at the top of the scm file filled with 00's which is space reserved for global vars. This is divided into blocks of 4 bytes, each var taking up one of these blocks. In compiled form, the global vars each point to somewhere in that block (or should do as otherwise writing to it will modify the actual code).


ExampleEdit

This code:

0001: wait 8 ms

0002: jump $var1

0050: gosub 1@

0051: return

...compiles as:

01 00 04 08 //wait opcode (First 2 bytes = opcode, next byte = 04 the parameter type for 8-bit int, and 08 is the actual value)

02 00 02 18 00 // jump opcode. The 18 00 would mean that the global var is stored at address 0x0018

50 00 03 01 00 //the gosub opcode

51 00 //the return opcode (it has no parameters)

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