SA SCM

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A scm file is a binary file with certain structure. The common information about what this file is for can be found here. The scm file structure looks like the following:

(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                         Segment id
  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                         Segment id
  32 bit int                 MAIN size
  32 bit int                 Largest mission size
  32 bit int                 Number of missions
  32 bit int                 Highest number of locals used in mission/exernal
  (mission addresses)        32 bit addresses * number of missions
(02 00 01)h + 32 bit int     Jump to fifth segment
byte                         Segment id
  32 bit int                 Largest external size
  32 bit int                 Number of externals
  (external data):           28 byte external data * number of externals
    20 bytes                 Name of external
    32 bit int               Offset of external
    32 bit int               Size of external
(02 00 01)h + 32 bit int     Jump to sixth segment
byte                         Segment id
  32 bit int                 (Unused, always 0)
(02 00 01)h + 32 bit int     Jump to seventh segment
byte                         Segment id
  32 bit int                 Size of global var space
   8 bit int                 Number of allocated externals (with 07D3, 0884, 0928 or 0929)? (unused, always 3Eh)
   8 bit int                 Number of unused externals (HOME_BRAINS and AAA)? (unused, always 2)
  16 bit int                 (Unused, always 0)
(MAIN code)                  MAIN section, equal to size defined earlier
(mission code)               The mission data, missions stored at offsets defined earlier

The AAA external script is very odd as the sixth segment is copied inside. The following bytes are just padding to align the file size to the nearest 2KB, like also in the working externals.

See also

• SCM language