| 33,25 → 33,9 |
|---|
| fs_dependent_data_start: |
| ; FATxx data |
| |
| SECTORS_PER_FAT dd 0x1f3a |
| NUMBER_OF_FATS dd 0x2 |
| SECTORS_PER_CLUSTER dd 0x8 |
| BYTES_PER_SECTOR dd 0x200 ; Note: if BPS <> 512 need lots of changes |
| ROOT_CLUSTER dd 2 ; first rootdir cluster |
| FAT_START dd 0 ; start of fat table |
| ROOT_START dd 0 ; start of rootdir (only fat16) |
| ROOT_SECTORS dd 0 ; count of rootdir sectors (only fat16) |
| DATA_START dd 0 ; start of data area (=first cluster 2) |
| LAST_CLUSTER dd 0 ; last availabe cluster |
| ADR_FSINFO dd 0 ; used only by fat32 |
| .partition dd ? |
| rb 80 |
| |
| fatRESERVED dd 0x0FFFFFF6 |
| fatBAD dd 0x0FFFFFF7 |
| fatEND dd 0x0FFFFFF8 |
| fatMASK dd 0x0FFFFFFF |
| |
| fatStartScan dd 2 |
| |
| fs_dependent_data_end: |
| file_system_data_size = $ - PARTITION_START |
| if file_system_data_size > 96 |
| 427,108 → 411,27 |
|---|
| cmp [hd_error], 0 |
| jnz problem_fat_dec_count |
| |
| cmp word [ebx+0x1fe], 0xaa55; is it valid boot sector? |
| jnz problem_fat_dec_count |
| |
| movzx eax, word [ebx+0xe]; sectors reserved |
| add eax, [PARTITION_START] |
| mov [FAT_START], eax; fat_start = partition_start + reserved |
| |
| movzx eax, byte [ebx+0xd]; sectors per cluster |
| push 0 |
| mov eax, [PARTITION_END] |
| sub eax, [PARTITION_START] |
| inc eax |
| push eax |
| push 0 |
| push [PARTITION_START] |
| push ebp |
| push ebp |
| mov ebp, esp |
| mov esi, 'old' ; special value: there is no DISK structure |
| push 1 ; bootsector read successfully |
| call fat_create_partition |
| add esp, 4*7 |
| test eax, eax |
| jz problem_fat_dec_count |
| mov [SECTORS_PER_CLUSTER], eax |
| mov [fs_dependent_data_start.partition], eax |
| mov al, [eax+FAT.fs_type] |
| mov [fs_type], al |
| |
| movzx ecx, word [ebx+0xb]; bytes per sector |
| cmp ecx, 0x200 |
| jnz problem_fat_dec_count |
| mov [BYTES_PER_SECTOR], ecx |
| |
| movzx eax, word [ebx+0x11]; count of rootdir entries (=0 fat32) |
| mov edx, 32 |
| mul edx |
| dec ecx |
| add eax, ecx ; round up if not equal count |
| inc ecx ; bytes per sector |
| div ecx |
| mov [ROOT_SECTORS], eax; count of rootdir sectors |
| |
| movzx eax, word [ebx+0x16]; sectors per fat <65536 |
| test eax, eax |
| jnz fat16_fatsize |
| mov eax, [ebx+0x24] ; sectors per fat |
| fat16_fatsize: |
| mov [SECTORS_PER_FAT], eax |
| |
| movzx eax, byte [ebx+0x10]; number of fats |
| test eax, eax ; if 0 it's not fat partition |
| jz problem_fat_dec_count |
| mov [NUMBER_OF_FATS], eax |
| imul eax, [SECTORS_PER_FAT] |
| add eax, [FAT_START] |
| mov [ROOT_START], eax; rootdir = fat_start + fat_size * fat_count |
| add eax, [ROOT_SECTORS]; rootdir sectors should be 0 on fat32 |
| mov [DATA_START], eax; data area = rootdir + rootdir_size |
| |
| movzx eax, word [ebx+0x13]; total sector count <65536 |
| test eax, eax |
| jnz fat16_total |
| mov eax, [ebx+0x20] ; total sector count |
| fat16_total: |
| add eax, [PARTITION_START] |
| dec eax |
| mov [PARTITION_END], eax |
| inc eax |
| sub eax, [DATA_START]; eax = count of data sectors |
| xor edx, edx |
| div dword [SECTORS_PER_CLUSTER] |
| inc eax |
| mov [LAST_CLUSTER], eax |
| dec eax ; cluster count |
| mov [fatStartScan], 2 |
| |
| ; limits by Microsoft Hardware White Paper v1.03 |
| cmp eax, 4085 ; 0xff5 |
| jb problem_fat_dec_count; fat12 not supported |
| cmp eax, 65525 ; 0xfff5 |
| jb fat16_partition |
| |
| fat32_partition: |
| mov eax, [ebx+0x2c] ; rootdir cluster |
| mov [ROOT_CLUSTER], eax |
| movzx eax, word [ebx+0x30]; fs info sector |
| add eax, [PARTITION_START] |
| mov [ADR_FSINFO], eax |
| call hd_read |
| mov eax, [ebx+0x1ec] |
| cmp eax, -1 |
| jz @f |
| mov [fatStartScan], eax |
| @@: |
| |
| popad |
| |
| mov [fatRESERVED], 0x0FFFFFF6 |
| mov [fatBAD], 0x0FFFFFF7 |
| mov [fatEND], 0x0FFFFFF8 |
| mov [fatMASK], 0x0FFFFFFF |
| mov [fs_type], 32 ; Fat32 |
| call free_hd_channel |
| mov [hd1_status], 0 ; free |
| ret |
| |
| fat16_partition: |
| xor eax, eax |
| mov [ROOT_CLUSTER], eax |
| |
| popad |
| |
| mov [fatRESERVED], 0x0000FFF6 |
| mov [fatBAD], 0x0000FFF7 |
| mov [fatEND], 0x0000FFF8 |
| mov [fatMASK], 0x0000FFFF |
| mov [fs_type], 16 ; Fat16 |
| call free_hd_channel |
| mov [hd1_status], 0 ; free |
| ret |
| |