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