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GP32 Executable format
Executeables, "Program Files":
------------------------------
GXB*,AXF,BIN Arm eXecutable Format: binary executable which starts with a
branch and 6 address fields
This is placed in gp32 ram starting at location 0xc000000. The
entry point is the starting location and the entry is
performed in ARM (not thumb) mode. Here is the header format:
b SkipHeader
DCD Start Of Rom Code @ (?)
DCD End Of Rom Code @ (?)
DCD Start Of BSS Section @ (?)
DCD End Of RAM Sections @ (?)
DCD Start Of DATA Section @ (?)
DCD End Of RAM Sections @ (?)
DCD 0x44450011
@ ... sometimes more info here...
SkipHeader:
b EntryPoint
GXE Gamepark eXecutable Encryption info: contains name, icon,
encryption info.
GXC Gamepark eXecutable Contents: contains the remaining part of
the executable data.
Usually only the first X bytes of a commercial gxc is
encrypted. The percentage of the file that is encrypted is
controlled by the encryption program. (But often it is a very
low percentage.) Here is the format
Header (20 bytes long)
Encypted binary data (X% of file)
Unencrypted binary data (100-X% of file)
If you remove the 20 byte header and unencrypt the file, then
the resulting data is identical in all other respects with a
.gxb file.
GXF Gamepark eXecutable Free/Format: plain executable with icon/
application info
[file header chunk]
0 - 3 : File ID. "gxf " (4byte)
4 - 7 : file size - 8 (4byte)
[info header chunk]
8 - 11 : info Header Size - (4byte)
12 - 12 : icon image flag (if 1, the icon image exists.) (1byte)
13 - 13 : the length of application program title= t_len (1byte)
14 - 13 + t_len : application program title(t_len byte)
14 + t_len - 13 + t_len + 256 : icon image data (256 byte)
[data chunk]
270 + t_len - 273 + t_len : axf (ARM excutable file) data size (4byte)
274 + t_len - : axf data (plain binary)
FXE Scrambled (light encryption) binary file & graphic icon for
free games/apps from GP & third party developers. You have to
use Game Park's free launcher to run these on your gp32. When
the launcher unscrambles these files and removes the icon, the
result is identical to a .gxb file. They are usually found in
the gp:\GPMM directory.
Resource Files:
---------------
GPG Graphic File
0 - 3 : File ID. "gpg " (4byte)
4 - 7 : Date size = file size - 8 (4byte)
8 - : Data
SEF PCM File
0 - 3 : File ID. "sef " (4byte)
4 - 7 : Data size = file size - 8 (4byte)
8 - : Data
GFT Font File
0 - 3 : File ID. "gft " (4byte)
4 - 7 : Data size = file size - 8 (4byte)
8 - : Data
Distribution Archives:
----------------------
ZPK ZPacKed archive: contains directory structure of an encrypted
application
FPK Free zPacKed archive: contains directory structure of a free
application
GPK unencrypted zPacK archive
SMC,GP* SmartMedia Card memory dump file
Security:
---------
GPS GamePark uSer: contains the username, password, GP32 ID (all
in encrypted format)
GPM* GamePark Media: contains the gamename (not defined), size (not
defined), SMC ID
*) not official
[info shamelessly copied from darkfader's site and some other source i dont
remember.]
