ファイルフォーマット - FAT

Directory Entry:
Offset Length Description
0x00 8 Filename (padded with spaces)
0x08 3 Extension
0x0B 1 File attributes
0x0C 1 Reserved
0x0D 1 Creation hundredths of a second (0..199)
0x0E 2 Creation time
0x10 2 Creation date
0x12 2 Access date
0x14 2 High halfword of cluster number
0x16 2 Last modified time
0x18 2 Last modified date
0x1A 2 Start cluster
0x1C 4 File size

File Attributes:
Bits Description
7..6 00
5 Archive
4 Directory
3 Volume Label
2 System
1 Hidden
0 Read-Only

Date Format:
Bits Description
15..9 Years since 1980 (0..127)
8..5 Month of year (1..12)
4..0 Day of month (1..31)

Time Format:
Bits Description
15..11 Hour (0..23)
10..5 Minutes (0..59)
4..0 Seconds/2 (0..29)

LFN Directory Entry:
Offset Length Description
0x00 1 LFN part number (bits 0..5), bit 6 indicates last entry
0x01 10 5 letters of LFN entry (Unicode)
0x0B 1 0x0F (attributes)
0x0C 1 0x00
0x0D 1 Checksum of short entry
0x0E 12 6 letters of LFN entry (Unicode)
0x1A 2 0x0000
0x1C 4 2 letters of LFN entry (Unicode)

More information on the FAT specification can be found in the offical Microsoft white paper at http://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx
Chishm's FAT library

Chishm has written a library to read and write files from a FAT formatted compact flash card, using a GBA Movie Player, Supercard CF, or M3 Perfect CF. You can obtain it from http://www.geocities.com/chishm1/gbamp.

To use it, add the sources to your project and include "gba_nds_fat.h" where needed. You must call FAT_InitFiles() before using any other functions, and allow at least one VBlank for the IPC to contain proper time data.

Files are always openned in binary mode, using:
FAT_FILE* file_handle = FAT_fopen ("path/filename", "mode");

Files can be read and written using standard fread and fwrite style calls to FAT_fread and FAT_fwrite. Much of Chishm's library mimics the standard file functions in this way.

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