diff --git a/kernel/fat16.h b/kernel/fat16.h new file mode 100644 index 0000000..dadafbb --- /dev/null +++ b/kernel/fat16.h @@ -0,0 +1,60 @@ +#ifndef FAT16_H +#define FAT16_H + +#include +#include + +/* FAT16 Constants */ +#define FAT16_SECTOR_SIZE 512 +#define FAT16_CLUSTER_SIZE 1 +#define FAT16_MAX_FILENAME_LEN 11 // 8.3 format +#define FAT16_ROOT_DIR_ENTRIES 224 // Fat16 root directory entries (typically 512 bytes per entry) + +#define FAT16_BOOT_SECTOR 0 +#define FAT16_FAT1_SECTOR 1 +#define FAT16_FAT2_SECTOR 2 +#define FAT16_ROOT_DIR_SECTOR 19 // First sector of root directory + +/* Boot Sector */ +typedef struct { + uint8_t jmp[3]; // Jump instruction to code + uint8_t oem_name[8]; // OEM Name + uint16_t bytes_per_sector; // Bytes per sector (512) + uint8_t sectors_per_cluster; // Sectors per cluster + uint16_t reserved_sectors; // Reserved sectors + uint8_t num_fats; // Number of FAT tables + uint16_t max_root_entries; // Max number of root directory entries + uint16_t total_sectors_16; // Total sectors in FAT16 + uint8_t media_type; // Media type (0xF8 = fixed drive) + uint16_t sectors_per_fat; // Sectors per FAT table + uint16_t sectors_per_track; // Sectors per track (for CHS addressing) + uint16_t num_heads; // Number of heads (for CHS addressing) + uint32_t hidden_sectors; // Hidden sectors (before the partition) + uint32_t total_sectors_32; // Total sectors in FAT16 (extended) +} __attribute__((packed)) fat16_boot_sector_t; + +/* FAT16 Directory Entry */ +typedef struct { + uint8_t name[8]; // File name (8 chars) + uint8_t ext[3]; // File extension (3 chars) + uint8_t attributes; // File attributes (e.g., directory, read-only) + uint8_t reserved; // Reserved + uint8_t creation_time[2]; // Creation time + uint8_t creation_date[2]; // Creation date + uint8_t last_access_date[2]; // Last access date + uint8_t first_cluster_high[2]; // High part of first cluster number + uint8_t last_mod_time[2]; // Last modification time + uint8_t last_mod_date[2]; // Last modification date + uint8_t first_cluster_low[2]; // Low part of first cluster number + uint32_t file_size; // File size in bytes +} __attribute__((packed)) fat16_dir_entry_t; + +/* Function Prototypes */ +bool mount_fat16(void); +bool read_sector(uint32_t lba, uint8_t* buffer); +bool write_sector(uint32_t lba, const uint8_t* buffer); +bool parse_fat16_boot_sector(void); +bool parse_fat16_root_dir(void); +bool read_fat16_entry(uint16_t entry_index, fat16_dir_entry_t* entry); + +#endif // FAT16_H