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Posted: Mon Jun 02, 2008 3:41 pm
by Alboin
01000101 wrote:It stands for both 'E' and 69. E for Ecstasy & 69 for ... 69. lol.
Your were doing ecstasy in 1969? Historically, wouldn't have LSD been more common? :lol:

Posted: Mon Jun 02, 2008 3:44 pm
by Brynet-Inc
Mr.E is a very naughty individual... ;)

Link is NSFW - Combuster

Posted: Mon Jun 02, 2008 3:50 pm
by SphinCorp
:D Your using autorunner? Wow your the first person to EVER download one of my programs lol. And yes I am working on my own bootloader.

Posted: Mon Jun 02, 2008 3:54 pm
by suthers
Yah I guess you could say I'm using it, I've tried it.
Jules

P.S. seriously first person?

To Brynet-Inc:
Didn't know that, you learn something new every day...

edit: Its not really a 'product' though, are you actually thinking of starting a company?

Posted: Mon Jun 02, 2008 3:58 pm
by SphinCorp
Completely unrelated funfact: The name Sphinx-WAP was decided on before I decided what "WAP" meant. I decided on "World Access Project". lolZ

Posted: Mon Jun 02, 2008 4:02 pm
by suthers
So are you planning to start your OSdev project now?
Jules

Posted: Mon Jun 02, 2008 4:07 pm
by SphinCorp
This is the bootloader I chose... Kernel now ;)?

Code: Select all

;*************************************************************************
;the ultimate boot-strap loader
;to load a file from a DOS FAT12 floppy as the OS
;*************************************************************************
[BITS 16]
[ORG 0x0000]
jmp     START
     
     OEM_ID                db "QUASI-OS"
     BytesPerSector        dw 0x0200
     SectorsPerCluster     db 0x01
     ReservedSectors       dw 0x0001
     TotalFATs             db 0x02
     MaxRootEntries        dw 0x00E0
     TotalSectorsSmall     dw 0x0B40
     MediaDescriptor       db 0xF0
     SectorsPerFAT         dw 0x0009
     SectorsPerTrack       dw 0x0012
     NumHeads              dw 0x0002
     HiddenSectors         dd 0x00000000
     TotalSectorsLarge     dd 0x00000000
     DriveNumber           db 0x00
     Flags                 db 0x00
     Signature             db 0x29
     VolumeID              dd 0xFFFFFFFF
     VolumeLabel           db "QUASI  BOOT"
     SystemID              db "FAT12   "
     
     START:
     ; code located at 0000:7C00, adjust segment registers
          cli
          mov     ax, 0x07C0
          mov     ds, ax
          mov     es, ax
          mov     fs, ax
          mov     gs, ax
     ; create stack
          mov     ax, 0x0000
          mov     ss, ax
          mov     sp, 0xFFFF
          sti
     ; post message
          mov     si, msgLoading
          call    DisplayMessage
     LOAD_ROOT:
     ; compute size of root directory and store in ‘cx’
          xor     cx, cx
          xor     dx, dx
          mov     ax, 0x0020                          ; 32 byte directory entry
          mul     WORD [MaxRootEntries]               ; total size of directory
          div     WORD [BytesPerSector]               ; sectors used by directory
          xchg    ax, cx
     ; compute location of root directory and store in ‘ax’
          mov     al, BYTE [TotalFATs]                ; number of FATs
          mul     WORD [SectorsPerFAT]                ; sectors used by FATs
          add     ax, WORD [ReservedSectors]          ; adjust for bootsector
          mov     WORD [datasector], ax               ; base of root directory
          add     WORD [datasector], cx
     ; read root directory into memory (7C00:0200)
          mov     bx, 0x0200                          ; copy root dir above bootcode
          call    ReadSectors
     ; browse root directory for binary image
          mov     cx, WORD [MaxRootEntries]           ; load loop counter
          mov     di, 0x0200                          ; locate first root entry
     .LOOP:
          push    cx
          mov     cx, 0x000B                          ; eleven character name
          mov     si, ImageName                       ; image name to find
          push    di
     rep  cmpsb                                       ; test for entry match
          pop     di
          je      LOAD_FAT
          pop     cx
          add     di, 0x0020                          ; queue next directory entry
          loop    .LOOP
          jmp     FAILURE
     LOAD_FAT:
     ; save starting cluster of boot image
          mov     si, msgCRLF
          call    DisplayMessage
          mov     dx, WORD [di + 0x001A]
          mov     WORD [cluster], dx                  ; file’s first cluster
     ; compute size of FAT and store in ‘cx’
          xor     ax, ax
          mov     al, BYTE [TotalFATs]                ; number of FATs
          mul     WORD [SectorsPerFAT]                ; sectors used by FATs
          mov     cx, ax
     ; compute location of FAT and store in ‘ax’
          mov     ax, WORD [ReservedSectors]          ; adjust for bootsector
     ; read FAT into memory (7C00:0200)
          mov     bx, 0x0200                          ; copy FAT above bootcode
          call    ReadSectors
     ; read image file into memory (0100:0000)
          mov     si, msgCRLF
          call    DisplayMessage
          mov     ax, 0x0100                          ; destination of image CS
          mov     es, ax
          mov     bx, 0x0000                          ; destination for image IP
          push    bx
     LOAD_IMAGE:
          mov     ax, WORD [cluster]                  ; cluster to read
          pop     bx                                  ; buffer to read into
          call    ClusterLBA                          ; convert cluster to LBA
          xor     cx, cx
          mov     cl, BYTE [SectorsPerCluster]        ; sectors to read
          call    ReadSectors
          push    bx
     ; compute next cluster
          mov     ax, WORD [cluster]                  ; identify current cluster
          mov     cx, ax                              ; copy current cluster
          mov     dx, ax                              ; copy current cluster
          shr     dx, 0x0001                          ;
     ;divide by two
          add     cx, dx                              ; sum for (3/2)
          mov     bx, 0x0200                          ; location of FAT in memory
          add     bx, cx                              ; index into FAT
          mov     dx, WORD [bx]                       ; read two bytes from FAT
          test    ax, 0x0001
          jnz     .ODD_CLUSTER
     .EVEN_CLUSTER:
          and     dx, 0000111111111111b               ; take low twelve bits
         jmp     .DONE
     .ODD_CLUSTER:
          shr     dx, 0x0004                          ; take high twelve bits
     .DONE:
          mov     WORD [cluster], dx                  ; store new cluster
          cmp     dx, 0x0FF0                          ; test for end of file
          jb      LOAD_IMAGE
     DONE:
          mov     si, msgCRLF
          call    DisplayMessage
          push    WORD 0x0100
          push    WORD 0x0000
          retf
     FAILURE:
          mov     si, msgFailure
          call    DisplayMessage
          mov     ah, 0x00
          int     0x16                                ; await keypress
          int     0x19                                ; warm boot computer
     
     ;*************************************************************************
     ; PROCEDURE DisplayMessage
     ; display ASCIIZ string at ds:si via BIOS
     ;*************************************************************************
     DisplayMessage:
          lodsb                                       ; load next character
          or      al, al                              ; test for NUL character
          jz      .DONE
          mov     ah, 0x0E                            ; BIOS teletype
          mov     bh, 0x00                            ; display page 0
          mov     bl, 0x07                            ; text attribute
          int     0x10                                ; invoke BIOS
          jmp     DisplayMessage
     .DONE:
          ret
     
     ;*************************************************************************
     ; PROCEDURE ReadSectors
     ; reads ‘cx’ sectors from disk starting at ‘ax’ into
     ;memory location ‘es:bx’
     ;*************************************************************************
     ReadSectors:
     .MAIN
          mov     di, 0x0005                          ; five retries for error
     .SECTORLOOP
          push    ax
          push    bx
          push    cx
          call    LBACHS
          mov     ah, 0x02                            ; BIOS read sector
          mov     al, 0x01                            ; read one sector
          mov     ch, BYTE [absoluteTrack]            ; track
          mov     cl, BYTE [absoluteSector]           ; sector
          mov     dh, BYTE [absoluteHead]             ; head
          mov     dl, BYTE [DriveNumber]              ; drive
          int     0x13                                ; invoke BIOS
          jnc     .SUCCESS                            ; test for read error
          xor     ax, ax                              ; BIOS reset disk
          int     0x13                                ; invoke BIOS
          dec     di                                  ; decrement error counter
          pop     cx
          pop     bx
          pop     ax
          jnz     .SECTORLOOP                         ; attempt to read again
          int     0x18
     .SUCCESS
          mov     si, msgProgress
          call    DisplayMessage
          pop     cx
          pop     bx
          pop     ax
          add     bx, WORD [BytesPerSector]           ; queue next buffer
          inc     ax                                  ; queue next sector
          loop    .MAIN                               ; read next sector
          ret
     
     ;*************************************************************************
     ; PROCEDURE ClusterLBA
     ; convert FAT cluster into LBA addressing scheme
     ; LBA = (cluster - 2) * sectors per cluster
     ;*************************************************************************
     ClusterLBA:
          sub     ax, 0x0002                          ; zero base cluster number
          xor     cx, cx
          mov     cl, BYTE [SectorsPerCluster]        ; convert byte to word
          mul     cx
          add     ax, WORD [datasector]               ; base data sector
          ret
     
     ;*************************************************************************
     ; PROCEDURE LBACHS
     ; convert ‘ax’ LBA addressing scheme to CHS addressing scheme
     ; absolute sector = (logical sector / sectors per track) + 1
     ; absolute head   = (logical sector / sectors per track) MOD number of heads
     ; absolute track  = logical sector / (sectors per track * number of heads)
     ;*************************************************************************
     LBACHS:
          xor     dx, dx                              ; prepare dx:ax for operation
          div     WORD [SectorsPerTrack]              ; calculate
          inc     dl                                  ; adjust for sector 0
          mov     BYTE [absoluteSector], dl
          xor     dx, dx                              ; prepare dx:ax for operation
          div     WORD [NumHeads]                     ; calculate
          mov     BYTE [absoluteHead], dl
          mov     BYTE [absoluteTrack], al
          ret

     absoluteSector db 0x00
     absoluteHead   db 0x00
     absoluteTrack  db 0x00
     
     datasector  dw 0x0000
     cluster     dw 0x0000
     ImageName   db "KERNEL  BIN"
     msgLoading  db 0x0D, 0x0A, "Loading Boot Image ", 0x0D, 0x0A, 0x00
     msgCRLF     db 0x0D, 0x0A, 0x00
     msgProgress db ".", 0x00
     msgFailure  db 0x0D, 0x0A, "ERROR : Press Any Key to Reboot", 0x00
     
          TIMES 510-($-$$) DB 0
          DW 0xAA55
     ;*************************************************************************

Posted: Mon Jun 02, 2008 4:27 pm
by suthers
1) This is off topic
2) You do realize your supposed to write your own code?, not just copy and pasted other people's code and fit it together.
3) here are the docs for fat32: http://www.osdever.net/documents/fatgen ... ?the_id=40
I didn't (or haven't yet more like) implement fat32 in my kernel so I won't be able to help you there, but again your looking at to grander things, if you want fat32 support you'll probably want a multi stage bootloader, so you will probably be wanting to figure out how to do that first...
and before you do anything else, I would recommend that you also figure out how to pass into pmode (important if you want to make a good modern OS (not that I'm saying anything about the people who have chosen to write their OS's in real mode, they often have very good reasons for this...)).
edit: addition to point one: make a new thread in the OS development forum.

Posted: Mon Jun 02, 2008 6:58 pm
by 01000101
Well seeing as how I wasn't even born until much later than 1969, that leaves only one other train of thought:
Brynet-Inc wrote:Mr.E is a very naughty individual... ;)
lol. :twisted:

anyways, I agree with the above poster, don't just copy and paste, get the code working, then alter it until it is COMPLETELY your own code that way you are not discouraged by not getting off the ground and still can learn without just popping in someone elses works.

Posted: Mon Jun 02, 2008 7:00 pm
by SphinCorp
I know... I followed a couple of tutorials, and got http://www.osdev.org/phpBB2/viewtopic.php?t=17147 this... Now I can get into PMode... But I still suck.

Posted: Mon Jun 02, 2008 7:03 pm
by 01000101
well as for implementing SFS, you need to write a harddrive/floppy/etc driver with support for that particular filesystem.

Posted: Mon Jun 02, 2008 7:15 pm
by SphinCorp
... How?

Posted: Mon Jun 02, 2008 7:46 pm
by piranha
It stands for both 'E' and 69. E for Ecstasy & 69 for ... 69. lol.
Laughs hysterically.

-JL

Posted: Tue Jun 03, 2008 3:22 am
by Combuster
Lets quit this before 010000101 begins to mean "NSFW" as well. :D Its grossly offtopic too

Posted: Tue Jun 03, 2008 7:17 am
by 01000101
I agree. Let it go. =)

anyways, you need to enter PMode, start writing a HDD driver (through either PIO or DMA) and then you can start implementing filesystems for it.