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File formats

Cahute aims at handling all file formats surrounding CASIO calculators, either defined by CASIO themselves or by software made by the community.

Note that there are several ways of exploring file formats by CASIO, depending on what your entrypoint is. The sections in this document

By format

The file formats described by topic are the following:

• fx-CG add-ins
• fx-9860G add-ins
• Calculator Text Format (CTF)
• CASIOLINK archives
  • CAS40 main memory file format
  • CAS50 main memory file format
• casrc configuration file
  • Well-known locations
  • File format
  • Available settings and properties
• Catalog files (CAT)
• e-Activity files
• fx-CG f-key files
• fx-9860G f-key files
• FX Program (FXP)
• GraphCard file format
• fx-CG language files
• fx-9860G language files
• Main memory archives
• fx-CG picture
• fx-CP picture

By extension

The file formats described by extension are the following:

Extension	Description
.C2P	fx-CP picture
.CAS	CASIOLINK archives
.CASRC	casrc configuration file
.CAT	Catalog files (CAT)
.CTF	Calculator Text Format (CTF)
.FXP	FX Program (FXP)
.G1A	fx-9860G add-ins
.G1E	e-Activity files
.G1L	fx-9860G language files
.G1M	Main memory archives
.G2R	Main memory archives
.G3A	fx-CG add-ins
.G3L	fx-CG language files
.G3M	Main memory archives
.G3P	fx-CG picture
.GRC	GraphCard file format

By CASIO container subtype

Multiple file formats by CASIO use what has been named a “standard header” by the community. Said header is 32 (0x20) bytes long, and is obfuscated by using bitwise NOT.

The format of this header is the following:

Offset	Size	Field name	Description	Values
0 (0x00)	14 B	File Type (FT)	Type of the file.	See the subsections below.
14 (0x0E)	1 B	Control 1 (C1)	First control byte.	Should be set to (FS + 0x41) & 0xFF.
15 (0x0F)	1 B	Reserved		Should be set to \0.
16 (0x10)	4 B	File Size (FS)		Big endian 32-bit integer.
20 (0x14)	1 B	Control 2 (C2)	Second control byte.	Should be set to (FS + 0xB8) & 0xFF.
21 (0x15)	7 B	Reserved		Should be set to \0.
28 (0x1C)	2 B	Obfuscation Options
30 (0x1E)	2 B	Object Count (OC)		Big endian 16-bit integer.

Some subtypes, mostly those for fx-CP and fx-CG models, have a “standard subheader”, which has the following format:

Offset	Size	Field name	Description	Values
0 (0x00)	4 B	Checksum (CS)		Big endian 32-bit integer.
4 (0x04)	1 B	File type (FT)
5 (0x05)	1 B	Target platform (FP)		Value set according to the targeted platform: Value Description 0x00 fx-CP. 0x01 fx-CG (Prizm).
6 (0x06)	4 B	Reserved.		Set to \0.
10 (0x0A)	4 B	Data Size (DS)		Big endian 32-bit integer.
14 (0x0E)	4 B	Control value (C3)		Big endian 32-bit integer. This should be set depending on the platform to: For the fx-CP, FS - 0x1000 - 4. For the fx-CG, FS - 0x7000 - 4.
18 (0x12)	4 B	Reserved.		Set to \0.
22 (0x16)	4 B	Message Zone Size (MZS)		Big endian 32-bit integer. Unreliable, may and should be set to 0.
26 (0x1A)	6 B	Targeted Add-in Platform (AP)		For C1A, should be set to GY437.
32 (0x20)	28 B	Title (T)	Title or language name.
60 (0x3C)	4 B	File Size (FS)		Big endian 32-bit integer.
64 (0x40)	11 B	Internal Add-in Name (IN)
75 (0x4B)	192 B	Language Labels		8 times a 24 bytes long string.
267 (0x10B)	1 B	e-Activity strip flag (EAS)		Available values are the following: Value Description 0x00 The e-Activity can’t be used. 0x01 The e-Activity can be used.
268 (0x10C)	4 B	Reserved		Set to \0.
272 (0x110)	10 B	Add-in version.
282 (0x11A)	2 B	Reserved.		Set to \0.
284 (0x11C)	14 B	Timestamp		YYYY.MMDD.HHmm-formatted date.

Known types for this container format are the following:

FT (StandardHeader)	FT (StandardSubheader)	Type
CASIO\0\0\0c2p\0\0\0	N/A	fx-CP picture
Ly755   \x2C\0\x01\0\x01\0	0x02	fx-CG f-key files
Ly755   \x2C\0\x01\0\x01\0	0x04	fx-CG language files
USBPower\x12\0\x10\0\x10\0	N/A	fx-9860G language files
USBPower\x2C\0\x01\0\x01\0	0x01	fx-CG add-ins
USBPower\x31\0\x10\0\x10\0	N/A	Main memory archives (fx-CP)
USBPower\x49\0\x10\0\x10\0	N/A	e-Activity files
USBPower\x62\0\x10\0\x10\0	N/A	Main memory archives (fx-9860G)
USBPower\x75\0\x10\0\x10\0	N/A	Main memory archives (fx-CG)
USBPower\x7D\0\x10\0\x10\0	N/A	fx-CG picture
USBPower\xF3\0\x10\0\x10\0	N/A	fx-9860G add-ins

Todo

Document the \xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF case, in which we need to use the extension instead of the format within the file.