| 108,6 → 108,7 |
|---|
| data dd ? |
| sad_size dd ? |
| search_start dd ? |
| sector_size_log dd ? |
| ends |
| |
| ; This structure represents a disk device and its media for the kernel. |
| 271,13 → 272,13 |
|---|
| endg |
| |
| iglobal |
| ; The function 'disk_scan_partitions' needs three 512-byte buffers for |
| ; The function 'disk_scan_partitions' needs three sector-sized buffers for |
| ; MBR, bootsector and fs-temporary sector data. It can not use the static |
| ; buffers always, since it can be called for two or more disks in parallel. |
| ; However, this case is not typical. We reserve three static 512-byte buffers |
| ; and a flag that these buffers are currently used. If 'disk_scan_partitions' |
| ; detects that the buffers are currently used, it allocates buffers from the |
| ; heap. |
| ; heap. Also, the heap is used when sector size is other than 512. |
| ; The flag is implemented as a global dword variable. When the static buffers |
| ; are not used, the value is -1. When the static buffers are used, the value |
| ; is normally 0 and temporarily can become greater. The function increments |
| 638,21 → 639,18 |
|---|
| ; 1. Initialize .NumPartitions and .Partitions fields as zeros: empty list. |
| and [esi+DISK.NumPartitions], 0 |
| and [esi+DISK.Partitions], 0 |
| ; 2. Currently we can work only with 512-bytes sectors. Check this restriction. |
| ; The only exception is 2048-bytes CD/DVD, but they are not supported yet by |
| ; this code. |
| cmp [esi+DISK.MediaInfo.SectorSize], 512 |
| jz .doscan |
| DEBUGF 1,'K : sector size is %d, only 512 is supported\n',[esi+DISK.MediaInfo.SectorSize] |
| ret |
| .doscan: |
| ; 3. Acquire the buffer for MBR and bootsector tests. See the comment before |
| ; 2. Acquire the buffer for MBR and bootsector tests. See the comment before |
| ; the 'partition_buffer_users' variable. |
| mov eax, [esi+DISK.MediaInfo.SectorSize] |
| cmp eax, 512 |
| jnz @f |
| mov ebx, mbr_buffer ; assume the global buffer is free |
| lock inc [partition_buffer_users] |
| jz .buffer_acquired ; yes, it is free |
| lock dec [partition_buffer_users] ; no, we must allocate |
| stdcall kernel_alloc, 512*3 |
| @@: |
| lea eax, [eax*3] |
| stdcall kernel_alloc, eax |
| test eax, eax |
| jz .nothing |
| xchg eax, ebx |
| 659,7 → 657,7 |
|---|
| .buffer_acquired: |
| ; MBR/EBRs are organized in the chain. We use a loop over MBR/EBRs, but no |
| ; more than MAX_NUM_PARTITION times. |
| ; 4. Prepare things for the loop. |
| ; 3. Prepare things for the loop. |
| ; ebp will hold the sector number for current MBR/EBR. |
| ; [esp] will hold the sector number for current extended partition, if there |
| ; is one. |
| 668,6 → 666,10 |
|---|
| push MAX_NUM_PARTITIONS ; the counter of max MBRs to process |
| xor ebp, ebp ; start from sector zero |
| push ebp ; no extended partition yet |
| ; 4. MBR is 512 bytes long. If sector size is less than 512 bytes, |
| ; assume no MBR, no partitions and go to 10. |
| cmp [esi+DISK.MediaInfo.SectorSize], 512 |
| jb .notmbr |
| .new_mbr: |
| ; 5. Read the current sector. |
| ; Note that 'read' callback operates with 64-bit sector numbers, so we must |
| 986,7 → 988,7 |
|---|
| ; a three-sectors-sized buffer. This function saves ebx in the stack |
| ; immediately before ebp. |
| mov ebx, [ebp-4] ; get buffer |
| add ebx, 512 ; advance over MBR data to bootsector data |
| add ebx, [esi+DISK.MediaInfo.SectorSize] ; advance over MBR data to bootsector data |
| add ebp, 8 ; ebp points to part of PARTITION structure |
| xor eax, eax ; first sector of the partition |
| call fs_read32_sys |
| 997,7 → 999,7 |
|---|
| ; ebp -> first three fields of PARTITION structure, .start, .length, .disk; |
| ; [esp] = error code after bootsector read: 0 = ok, otherwise = failed, |
| ; ebx points to the buffer for bootsector, |
| ; ebx+512 points to 512-bytes buffer that can be used for anything. |
| ; ebx+[esi+DISK.MediaInfo.SectorSize] points to sector-sized buffer that can be used for anything. |
| call fat_create_partition |
| test eax, eax |
| jnz .success |