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[EXT2]

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Fix remaining issues, bootsector compiles with GAS and ML. Sadly GAs sucks a bit and does neither allow to specify byte offsets, nor does it chose this itself to save space. As a result the code gets several bytes larger and I had to trim the messages even more.

svn path=/trunk/; revision=53938
This commit is contained in:
Timo Kreuzer 2011-10-02 19:45:41 +00:00
parent ec00096fc0
commit e8469d97f6
2 changed files with 99 additions and 90 deletions
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8
reactos/boot/freeldr/bootsect/CMakeLists.txt
View file

@ -2,7 +2,7 @@
if(ARCH MATCHES i386 OR ARCH MATCHES amd64) if(ARCH MATCHES i386 OR ARCH MATCHES amd64)
CreateBootSectorTarget2(dosmbr ${CMAKE_CURRENT_SOURCE_DIR}/dosmbr.S ${CMAKE_CURRENT_BINARY_DIR}/dosmbr.bin 7c00) CreateBootSectorTarget2(dosmbr ${CMAKE_CURRENT_SOURCE_DIR}/dosmbr.S ${CMAKE_CURRENT_BINARY_DIR}/dosmbr.bin 7c00)
#CreateBootSectorTarget2(ext2 ${CMAKE_CURRENT_SOURCE_DIR}/ext2.S ${CMAKE_CURRENT_BINARY_DIR}/ext2.bin 0) CreateBootSectorTarget2(ext2 ${CMAKE_CURRENT_SOURCE_DIR}/ext2.S ${CMAKE_CURRENT_BINARY_DIR}/ext2.bin 0)
CreateBootSectorTarget2(fat32 ${CMAKE_CURRENT_SOURCE_DIR}/fat32.S ${CMAKE_CURRENT_BINARY_DIR}/fat32.bin 7c00) CreateBootSectorTarget2(fat32 ${CMAKE_CURRENT_SOURCE_DIR}/fat32.S ${CMAKE_CURRENT_BINARY_DIR}/fat32.bin 7c00)
CreateBootSectorTarget2(fat ${CMAKE_CURRENT_SOURCE_DIR}/fat.S ${CMAKE_CURRENT_BINARY_DIR}/fat.bin 7c00) CreateBootSectorTarget2(fat ${CMAKE_CURRENT_SOURCE_DIR}/fat.S ${CMAKE_CURRENT_BINARY_DIR}/fat.bin 7c00)
CreateBootSectorTarget2(isoboot ${CMAKE_CURRENT_SOURCE_DIR}/isoboot.S ${CMAKE_CURRENT_BINARY_DIR}/isoboot.bin 7000) CreateBootSectorTarget2(isoboot ${CMAKE_CURRENT_SOURCE_DIR}/isoboot.S ${CMAKE_CURRENT_BINARY_DIR}/isoboot.bin 7000)
@ -13,11 +13,7 @@ add_cd_file(TARGET fat32 DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_D
add_cd_file(TARGET fat DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/fat.bin FOR all) add_cd_file(TARGET fat DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/fat.bin FOR all)
add_cd_file(TARGET isoboot DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/isoboot.bin FOR all) add_cd_file(TARGET isoboot DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/isoboot.bin FOR all)
add_cd_file(TARGET isobtrt DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/isobtrt.bin FOR all) add_cd_file(TARGET isobtrt DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/isobtrt.bin FOR all)
add_cd_file(TARGET ext2 DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/ext2.bin FOR all)
if(NOT MSVC)
CreateBootSectorTarget(ext2 ${CMAKE_CURRENT_SOURCE_DIR}/ext2.asm ${CMAKE_CURRENT_BINARY_DIR}/ext2.bin 0)
add_cd_file(TARGET ext2 DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/ext2.bin FOR all)
endif()
endif() endif()

181
reactos/boot/freeldr/bootsect/ext2.S
View file

@ -7,6 +7,9 @@
// [bp-0x0c] Here we will store the size of the disk as the BIOS reports in CHS form // [bp-0x0c] Here we will store the size of the disk as the BIOS reports in CHS form
// [bp-0x10] Here we will store the number of LBA sectors read // [bp-0x10] Here we will store the number of LBA sectors read
#include <asm.inc>
.code16
SECTORS_PER_TRACK = HEX(04) SECTORS_PER_TRACK = HEX(04)
NUMBER_OF_HEADS = HEX(08) NUMBER_OF_HEADS = HEX(08)
BIOS_CHS_DRIVE_SIZE = HEX(0C) BIOS_CHS_DRIVE_SIZE = HEX(0C)
@ -18,40 +21,46 @@ EXT2_S_IFMT = HEX(0f0)
EXT2_S_IFREG = HEX(080) EXT2_S_IFREG = HEX(080)
org 7c00h //org 7c00h
segment .text
bits 16
start: start:
jmp short main jmp short main
nop nop
BootDrive db HEX(80) BootDrive:
.byte HEX(80)
//BootPartition db 0 // Moved to end of boot sector to have a standard format across all boot sectors //BootPartition db 0 // Moved to end of boot sector to have a standard format across all boot sectors
//SectorsPerTrack db 63 // Moved to [bp-SECTORS_PER_TRACK] //SectorsPerTrack db 63 // Moved to [bp-SECTORS_PER_TRACK]
//NumberOfHeads dw 16 // Moved to [bp-NUMBER_OF_HEADS] //NumberOfHeads dw 16 // Moved to [bp-NUMBER_OF_HEADS]
//BiosCHSDriveSize dd (1024 * 1024 * 63) // Moved to [bp-BIOS_CHS_DRIVE_SIZE] //BiosCHSDriveSize dd (1024 * 1024 * 63) // Moved to [bp-BIOS_CHS_DRIVE_SIZE]
//LBASectorsRead dd 0 // Moved to [bp-LBA_SECTORS_READ] //LBASectorsRead dd 0 // Moved to [bp-LBA_SECTORS_READ]
Ext2VolumeStartSector dd 263088 // Start sector of the ext2 volume Ext2VolumeStartSector:
Ext2BlockSize dd 2 // Block size in sectors .long 263088 // Start sector of the ext2 volume
Ext2BlockSizeInBytes dd 1024 // Block size in bytes Ext2BlockSize:
Ext2PointersPerBlock dd 256 // Number of block pointers that can be contained in one block .long 2 // Block size in sectors
Ext2GroupDescPerBlock dd 32 // Number of group descriptors per block Ext2BlockSizeInBytes:
Ext2FirstDataBlock dd 1 // First data block (1 for 1024-byte blocks, 0 for bigger sizes) .long 1024 // Block size in bytes
Ext2InodesPerGroup dd 2048 // Number of inodes per group Ext2PointersPerBlock:
Ext2InodesPerBlock dd 8 // Number of inodes per block .long 256 // Number of block pointers that can be contained in one block
Ext2GroupDescPerBlock:
.long 32 // Number of group descriptors per block
Ext2FirstDataBlock:
.long 1 // First data block (1 for 1024-byte blocks, 0 for bigger sizes)
Ext2InodesPerGroup:
.long 2048 // Number of inodes per group
Ext2InodesPerBlock:
.long 8 // Number of inodes per block
Ext2ReadEntireFileLoadSegment: Ext2ReadEntireFileLoadSegment:
dw 0 .word 0
Ext2InodeIndirectPointer: Ext2InodeIndirectPointer:
dd 0 .long 0
Ext2InodeDoubleIndirectPointer: Ext2InodeDoubleIndirectPointer:
dd 0 .long 0
Ext2BlocksLeftToRead: Ext2BlocksLeftToRead:
dd 0 .long 0
main: main:
xor ax,ax // Setup segment registers xor ax,ax // Setup segment registers
@ -61,16 +70,16 @@ main:
mov bp, HEX(7c00) mov bp, HEX(7c00)
mov sp, HEX(7b00) // Setup a stack mov sp, HEX(7b00) // Setup a stack
mov si, offset BootDrive
cmp byte ptr [bp+BootDrive], HEX(0ff) // If they have specified a boot drive then use it cmp byte ptr [si], HEX(0ff) // If they have specified a boot drive then use it
jne GetDriveParameters jne GetDriveParameters
mov [bp+BootDrive],dl // Save the boot drive mov [si],dl // Save the boot drive
GetDriveParameters: GetDriveParameters:
mov ah,08h mov ah, 8
mov dl,[bp+BootDrive] // Get boot drive in dl mov dl,[si] // Get boot drive in dl
int HEX(13) // Request drive parameters from the bios int HEX(13) // Request drive parameters from the bios
jnc CalcDriveSize // If the call succeeded then calculate the drive size jnc CalcDriveSize // If the call succeeded then calculate the drive size
@ -125,7 +134,7 @@ Ext2ReadGroupDesc:
shl eax,5 // Group = (Group * sizeof(GROUP_DESCRIPTOR) /* 32 */) shl eax,5 // Group = (Group * sizeof(GROUP_DESCRIPTOR) /* 32 */)
xor edx,edx xor edx,edx
div dword ptr [bp+Ext2GroupDescPerBlock] // Group = (Group / Ext2GroupDescPerBlock) div dword ptr [bp+Ext2GroupDescPerBlock] // Group = (Group / Ext2GroupDescPerBlock)
add eax, [bp+Ext2FirstDataBlock] // Group = Group + Ext2FirstDataBlock + 1 add eax, dword ptr [bp+Ext2FirstDataBlock] // Group = Group + Ext2FirstDataBlock + 1
inc eax // EAX now has the group descriptor block number inc eax // EAX now has the group descriptor block number
// EDX now has the group descriptor offset in the block // EDX now has the group descriptor offset in the block
@ -142,10 +151,10 @@ Ext2ReadGroupDesc:
// Instead of using the call instruction we will // Instead of using the call instruction we will
// just put Ext2ReadBlock right after this routine // just put Ext2ReadBlock right after this routine
// Reads ext2 block into [ES:BX] // Reads ext2 block into ES:[BX]
// EAX has logical block number to read // EAX has logical block number to read
Ext2ReadBlock: Ext2ReadBlock:
mov ecx, [bp+Ext2BlockSize] mov ecx, dword ptr [bp+Ext2BlockSize]
mul ecx mul ecx
jmp ReadSectors jmp ReadSectors
@ -193,11 +202,11 @@ Ext2ReadInode:
ret ret
// Reads logical sectors into [ES:BX] // Reads logical sectors into ES:[BX]
// EAX has logical sector number to read // EAX has logical sector number to read
// CX has number of sectors to read // CX has number of sectors to read
ReadSectors: ReadSectors:
add eax, [bp+Ext2VolumeStartSector] // Add the start of the volume add eax, dword ptr [bp+Ext2VolumeStartSector] // Add the start of the volume
cmp eax, [bp-BIOS_CHS_DRIVE_SIZE] // Check if they are reading a sector outside CHS range cmp eax, [bp-BIOS_CHS_DRIVE_SIZE] // Check if they are reading a sector outside CHS range
jae ReadSectorsLBA // Yes - go to the LBA routine jae ReadSectorsLBA // Yes - go to the LBA routine
// If at all possible we want to use LBA routines because // If at all possible we want to use LBA routines because
@ -208,7 +217,7 @@ ReadSectors:
CheckInt13hExtensions: // Now check if this computer supports extended reads CheckInt13hExtensions: // Now check if this computer supports extended reads
mov ah, HEX(41) // AH = 41h mov ah, HEX(41) // AH = 41h
mov bx, HEX(55aa) // BX = 55AAh mov bx, HEX(55aa) // BX = 55AAh
mov dl,[bp+BootDrive] // DL = drive (80h-FFh) mov dl, byte ptr [bp+BootDrive] // DL = drive (80h-FFh)
int HEX(13) // IBM/MS INT 13 Extensions - INSTALLATION CHECK int HEX(13) // IBM/MS INT 13 Extensions - INSTALLATION CHECK
jc ReadSectorsCHS // CF set on error (extensions not supported) jc ReadSectorsCHS // CF set on error (extensions not supported)
cmp bx, HEX(0aa55) // BX = AA55h if installed cmp bx, HEX(0aa55) // BX = AA55h if installed
@ -228,7 +237,7 @@ ReadSectorsLBA:
ReadSectorsSetupDiskAddressPacket: ReadSectorsSetupDiskAddressPacket:
mov [bp-LBA_SECTORS_READ],cx mov [bp-LBA_SECTORS_READ],cx
mov word ptr [bp-LBA_SECTORS_READ+2],0 mov word ptr [bp-LBA_SECTORS_READ+2],0
o32 push 0 data32 push 0
push eax // Put 64-bit logical block address on stack push eax // Put 64-bit logical block address on stack
push es // Put transfer segment on stack push es // Put transfer segment on stack
push bx // Put transfer offset on stack push bx // Put transfer offset on stack
@ -237,9 +246,9 @@ ReadSectorsSetupDiskAddressPacket:
mov si,sp // Setup disk address packet on stack mov si,sp // Setup disk address packet on stack
mov dl, [bp+BootDrive] // Drive number mov dl, byte ptr [bp+BootDrive] // Drive number
mov ah,42h // Int 13h, AH = 42h - Extended Read mov ah, HEX(42) // Int 13h, AH = 42h - Extended Read
int 13h // Call BIOS int HEX(13) // Call BIOS
jc PrintDiskError // If the read failed then abort jc PrintDiskError // If the read failed then abort
add sp, 16 // Remove disk address packet from stack add sp, 16 // Remove disk address packet from stack
@ -247,7 +256,7 @@ ReadSectorsSetupDiskAddressPacket:
popad // Restore sector count & logical sector number popad // Restore sector count & logical sector number
push bx push bx
mov ebx,DWORD [bp-LBA_SECTORS_READ] mov ebx, [bp-LBA_SECTORS_READ]
add eax,ebx // Increment sector to read add eax,ebx // Increment sector to read
shl ebx,5 shl ebx,5
mov dx,es mov dx,es
@ -261,7 +270,7 @@ ReadSectorsSetupDiskAddressPacket:
ret ret
// Reads logical sectors into [ES:BX] // Reads logical sectors into ES:[BX]
// EAX has logical sector number to read // EAX has logical sector number to read
// CX has number of sectors to read // CX has number of sectors to read
ReadSectorsCHS: ReadSectorsCHS:
@ -270,15 +279,15 @@ ReadSectorsCHS:
ReadSectorsCHSLoop: ReadSectorsCHSLoop:
pushad pushad
xor edx,edx xor edx,edx
mov ecx,DWORD [bp-SECTORS_PER_TRACK] mov ecx, [bp-SECTORS_PER_TRACK]
div ecx // Divide logical by SectorsPerTrack div ecx // Divide logical by SectorsPerTrack
inc dl // Sectors numbering starts at 1 not 0 inc dl // Sectors numbering starts at 1 not 0
mov cl,dl // Sector in CL mov cl,dl // Sector in CL
mov edx,eax mov edx,eax
shr edx,16 shr edx,16
div WORD [bp-NUMBER_OF_HEADS] // Divide logical by number of heads div word ptr [bp-NUMBER_OF_HEADS] // Divide logical by number of heads
mov dh,dl // Head in DH mov dh,dl // Head in DH
mov dl,[bp+BootDrive] // Drive number in DL mov dl, byte ptr [bp+BootDrive] // Drive number in DL
mov ch,al // Cylinder in CX mov ch,al // Cylinder in CX
ror ah,2 // Low 8 bits of cylinder in CH, high 2 bits ror ah,2 // Low 8 bits of cylinder in CH, high 2 bits
// in CL shifted to bits 6 & 7 // in CL shifted to bits 6 & 7
@ -316,8 +325,8 @@ Reboot:
mov si,msgAnyKey // Press any key message mov si,msgAnyKey // Press any key message
call PutChars // Display it call PutChars // Display it
xor ax,ax xor ax,ax
int 16h // Wait for a keypress int HEX(16) // Wait for a keypress
int 19h // Reboot int HEX(19) // Reboot
PutChars: PutChars:
lodsb lodsb
@ -326,16 +335,16 @@ PutChars:
call PutCharsCallBios call PutCharsCallBios
jmp short PutChars jmp short PutChars
PutCharsCallBios: PutCharsCallBios:
mov ah,0eh mov ah, HEX(0e)
mov bx,07h mov bx, HEX(07)
int 10h int HEX(10)
retn ret
Done: Done:
mov al,0dh mov al, HEX(0d)
call PutCharsCallBios call PutCharsCallBios
mov al,0ah mov al, HEX(0a)
call PutCharsCallBios call PutCharsCallBios
retn ret
@ -344,14 +353,15 @@ msgDiskError:
// Sorry, need the space... // Sorry, need the space...
//msgAnyKey db 'Press any key to restart',0 //msgAnyKey db 'Press any key to restart',0
msgAnyKey: msgAnyKey:
.ascii "Press any key", NUL .ascii "Press key", NUL
times 509-($-$$) db 0 // Pad to 509 bytes // times 509-($-$$) db 0 // Pad to 509 bytes
.org 509
BootPartition: BootPartition:
db 0 .byte 0
dw HEX(0aa55) // BootSector signature .word HEX(0aa55) // BootSector signature
// End of bootsector // End of bootsector
@ -367,14 +377,14 @@ LoadRootDirectory:
call Ext2ReadInode // Read in the inode call Ext2ReadInode // Read in the inode
// Point ES:DI to the inode structure at 6000:8000 // Point ES:DI to the inode structure at 6000:8000
push WORD HEX(6000) push HEX(6000)
pop es pop es
mov di, HEX(8000) mov di, HEX(8000)
push di push di
push es // Save these for later push es // Save these for later
// Get root directory size from inode structure // Get root directory size from inode structure
mov eax, [es:di+4] mov eax, es:[di+4]
push eax push eax
// Now that the inode has been read in load // Now that the inode has been read in load
@ -410,7 +420,7 @@ SearchRootDirectory:
jz FoundFile jz FoundFile
// Nope, didn't find it in this entry, keep looking // Nope, didn't find it in this entry, keep looking
movzx ecx,word ptr [es:di+4] movzx ecx,word ptr es:[di+4]
add edx,ecx add edx,ecx
// Check to see if we have reached the // Check to see if we have reached the
@ -420,14 +430,14 @@ SearchRootDirectory:
jmp PrintFileNotFound jmp PrintFileNotFound
FoundFile: FoundFile:
mov eax,[es:di] // Get inode number from directory entry mov eax,es:[di] // Get inode number from directory entry
call Ext2ReadInode // Read in the inode call Ext2ReadInode // Read in the inode
// Point ES:DI to the inode structure at 6000:8000 // Point ES:DI to the inode structure at 6000:8000
pop es pop es
pop di // These were saved earlier pop di // These were saved earlier
mov cx,[es:di] // Get the file mode so we can make sure it's a regular file mov cx, es:[di] // Get the file mode so we can make sure it's a regular file
and ch,EXT2_S_IFMT // Mask off everything but the file type and ch,EXT2_S_IFMT // Mask off everything but the file type
cmp ch,EXT2_S_IFREG // Make sure it's a regular file cmp ch,EXT2_S_IFREG // Make sure it's a regular file
je LoadFreeLoader je LoadFreeLoader
@ -439,8 +449,8 @@ LoadFreeLoader:
call Ext2ReadEntireFile // Read freeldr.sys to 0000:8000 call Ext2ReadEntireFile // Read freeldr.sys to 0000:8000
mov dl,[bp+BootDrive] mov dl, byte ptr [bp+BootDrive]
mov dh,[bp+BootPartition] mov dh, byte ptr [bp+BootPartition]
push 0 // push segment (0x0000) push 0 // push segment (0x0000)
mov eax, [HEX(8000) + HEX(0A8)] // load the RVA of the EntryPoint into eax mov eax, [HEX(8000) + HEX(0A8)] // load the RVA of the EntryPoint into eax
add eax, HEX(8000) // RVA -> VA add eax, HEX(8000) // RVA -> VA
@ -470,7 +480,7 @@ Ext2ReadEntireFile:
// We will do this by rounding the // We will do this by rounding the
// file size up to the next block // file size up to the next block
// size and then dividing by the block size // size and then dividing by the block size
mov eax,DWORD [bp+Ext2BlockSizeInBytes] // Get the block size in bytes mov eax, dword ptr [bp+Ext2BlockSizeInBytes] // Get the block size in bytes
push eax push eax
dec eax // Ext2BlockSizeInBytes -= 1 dec eax // Ext2BlockSizeInBytes -= 1
add eax, es:[di+4] // Add the file size add eax, es:[di+4] // Add the file size
@ -480,22 +490,22 @@ Ext2ReadEntireFile:
push eax push eax
// Make sure the file size isn't zero // Make sure the file size isn't zero
cmp eax,byte 0 cmp eax, 0
jnz Ext2ReadEntireFile2 jnz Ext2ReadEntireFile2
jmp PrintFileSizeError jmp PrintFileSizeError
Ext2ReadEntireFile2: Ext2ReadEntireFile2:
// Save the indirect & double indirect pointers // Save the indirect & double indirect pointers
mov edx,DWORD [es:di+ HEX(58)] // Get indirect pointer mov edx, es:[di+ HEX(58)] // Get indirect pointer
mov [bp+Ext2InodeIndirectPointer],edx // Save indirect pointer mov dword ptr [bp+Ext2InodeIndirectPointer], edx // Save indirect pointer
mov edx,DWORD [es:di+ HEX(5c)] // Get double indirect pointer mov edx, es:[di+ HEX(5c)] // Get double indirect pointer
mov [bp+Ext2InodeDoubleIndirectPointer],edx // Save double indirect pointer mov dword ptr [bp+Ext2InodeDoubleIndirectPointer],edx // Save double indirect pointer
// Now copy the direct pointers to 7000:0000 // Now copy the direct pointers to 7000:0000
// so that we can call Ext2ReadDirectBlocks // so that we can call Ext2ReadDirectBlocks
push ds // Save DS push ds // Save DS
push es push es
push WORD HEX(7000) push HEX(7000)
pop es pop es
pop ds pop ds
mov si, HEX(8028) mov si, HEX(8028)
@ -513,15 +523,15 @@ Ext2ReadEntireFile2:
// Check to see if we actually have // Check to see if we actually have
// blocks left to read // blocks left to read
cmp eax,byte 0 cmp eax, 0
jz Ext2ReadEntireFileDone jz Ext2ReadEntireFileDone
// Now we have read all the direct blocks in // Now we have read all the direct blocks in
// the inode. So now we have to read the indirect // the inode. So now we have to read the indirect
// block and read all it's direct blocks // block and read all it's direct blocks
push eax // Save the total block count push eax // Save the total block count
mov eax,DWORD [BYTE bp+Ext2InodeIndirectPointer] // Get the indirect block pointer mov eax, dword ptr [bp+Ext2InodeIndirectPointer] // Get the indirect block pointer
push WORD HEX(7000) push HEX(7000)
pop es pop es
xor bx,bx // Set the load address to 7000:0000 xor bx,bx // Set the load address to 7000:0000
call Ext2ReadBlock // Read the block call Ext2ReadBlock // Read the block
@ -529,7 +539,7 @@ Ext2ReadEntireFile2:
// Now we have all the block pointers from the // Now we have all the block pointers from the
// indirect block in the right location so read them in // indirect block in the right location so read them in
pop eax // Restore the total block count pop eax // Restore the total block count
mov ecx,DWORD [BYTE bp+Ext2PointersPerBlock] // Get the number of block pointers that one block contains mov ecx, dword ptr [bp+Ext2PointersPerBlock] // Get the number of block pointers that one block contains
call Ext2ReadDirectBlockList call Ext2ReadDirectBlockList
// Check to see if we actually have // Check to see if we actually have
@ -542,9 +552,9 @@ Ext2ReadEntireFile2:
// we have to read the double indirect block // we have to read the double indirect block
// and read all it's indirect blocks // and read all it's indirect blocks
// (whew, it's a good thing I don't support triple indirect blocks) // (whew, it's a good thing I don't support triple indirect blocks)
mov [bp+Ext2BlocksLeftToRead],eax // Save the total block count mov dword ptr [bp+Ext2BlocksLeftToRead],eax // Save the total block count
mov eax,DWORD [bp+Ext2InodeDoubleIndirectPointer] // Get the double indirect block pointer mov eax, dword ptr [bp+Ext2InodeDoubleIndirectPointer] // Get the double indirect block pointer
push WORD HEX(7800) push HEX(7800)
pop es pop es
push es // Save an extra copy of this value on the stack push es // Save an extra copy of this value on the stack
xor bx,bx // Set the load address to 7000:8000 xor bx,bx // Set the load address to 7000:8000
@ -554,28 +564,28 @@ Ext2ReadEntireFile2:
xor di,di xor di,di
Ext2ReadIndirectBlock: Ext2ReadIndirectBlock:
mov eax,DWORD [es:di] // Get indirect block pointer mov eax, es:[di] // Get indirect block pointer
add di,BYTE 4 // Update DI for next array index add di, 4 // Update DI for next array index
push es push es
push di push di
push WORD HEX(7000) push HEX(7000)
pop es pop es
xor bx,bx // Set the load address to 7000:0000 xor bx,bx // Set the load address to 7000:0000
call Ext2ReadBlock // Read the indirect block call Ext2ReadBlock // Read the indirect block
// Now we have all the block pointers from the // Now we have all the block pointers from the
// indirect block in the right location so read them in // indirect block in the right location so read them in
mov eax,DWORD [bp+Ext2BlocksLeftToRead] // Restore the total block count mov eax, dword ptr [bp+Ext2BlocksLeftToRead] // Restore the total block count
mov ecx,DWORD [bp+Ext2PointersPerBlock] // Get the number of block pointers that one block contains mov ecx, dword ptr [bp+Ext2PointersPerBlock] // Get the number of block pointers that one block contains
call Ext2ReadDirectBlockList call Ext2ReadDirectBlockList
mov [bp+Ext2BlocksLeftToRead],eax // Save the total block count mov dword ptr [bp+Ext2BlocksLeftToRead],eax // Save the total block count
pop di pop di
pop es pop es
// Check to see if we actually have // Check to see if we actually have
// blocks left to read // blocks left to read
cmp eax,byte 0 cmp eax, 0
jnz Ext2ReadIndirectBlock jnz Ext2ReadIndirectBlock
Ext2ReadEntireFileDone: Ext2ReadEntireFileDone:
@ -606,12 +616,12 @@ CallExt2ReadDirectBlocks:
// CX contains the number of blocks to read // CX contains the number of blocks to read
Ext2ReadDirectBlocks: Ext2ReadDirectBlocks:
push WORD HEX(7000) push HEX(7000)
pop es pop es
xor di,di // Set ES:DI = 7000:0000 xor di,di // Set ES:DI = 7000:0000
Ext2ReadDirectBlocksLoop: Ext2ReadDirectBlocksLoop:
mov eax,[es:di] // Get direct block pointer from array mov eax,es:[di] // Get direct block pointer from array
add di, 4 // Update DI for next array index add di, 4 // Update DI for next array index
push cx // Save number of direct blocks left push cx // Save number of direct blocks left
@ -660,14 +670,17 @@ DisplayItAndReboot:
msgFreeLdr: msgFreeLdr:
.ascii "freeldr.sys not found", NUL .ascii "freeldr.sys not found", NUL
msgFileSize: msgFileSize:
.ascii "File size is 0", NUL .ascii "File size 0", NUL
msgRegFile: msgRegFile:
.ascii "freeldr.sys isnt a regular file", NUL .ascii "freeldr.sys isnt a regular file", NUL
filename: filename:
.ascii "freeldr.sys" .ascii "freeldr.sys"
msgLoading: msgLoading:
.ascii "Loading FreeLoader...", NUL .ascii "Loading...", NUL
times 1022-($-$$) db 0 // Pad to 1022 bytes // times 1022-($-$$) db 0 // Pad to 1022 bytes
.org 1022
dw HEX(0aa55) // BootSector signature .word HEX(0aa55) // BootSector signature
END