fortuna-fat32

A very small (< 8 kB) and memory conscious (< 40 bytes + a shared 512 byte buffer) C ANSI code for accessing FAT32 images. Compilable to both AVR and x64, for use in Fortuna computers and emulator.

Special registers

• F_RSLT: result of the last operation

Current limitations

• Will only work in the first partition of a single disk.

Supported operations

All operations return 0 on success or various errors.

Disk operations:

Operation	Description	Input	Output
F_FREE	Free disk space (from FSInfo)	-	000 - 003: Space, in clusters
F_BOOT	Load boot sector	-	The 512-byte boot sector
F_FSINFO_RECALC	Recalculate values in FSINFO	-	-

Directory operations:

(directory could be a path relative to current dir, or an absolute path starting with '/')

Operation	Description	Input	Output
F_DIR	List contents of current directory	0: start over; 1: continue	Directory listing (same structure as FAT32)
F_CD	Change directory	Directory path	-
F_MKDIR	Create a directory	Directory path	-
F_RMDIR	Remove a directory	Directory path	-

File operations:

Operation	Description	Input	Output
F_OPEN	Open or create a file	File name + attributes (see below)	File number
F_CLOSE	Close file	File number	-
F_READ	Read block	File number, block number	Number of bytes left
F_WRITE	Write block	File number, block number	Number of bytes to write
F_RM	Remove file	File/Directory name	-

Operations that work both in files and directories:

Operation	Description	Input	Output
F_STAT	Read file/dir information	File/dir name	File in directory listing (same structure as FAT32
F_MV	Rename/move directory	Old file/directory name, new file/directory name	-

Structures

F_OPEN request values (TODO)

Return values:

Value	Meaning
0	Success - end of operation
1	Success - more data available
>1	Failure