Subversion Repositories Kolibri OS

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;;                                                              ;;

;; Copyright (C) KolibriOS team 2004-2007. All rights reserved. ;;

;; Copyright (C) MenuetOS 2000-2004 Ville Mikael Turjanmaa      ;;

;; Distributed under terms of the GNU General Public License    ;;

;;                                                              ;;

;;  BOOTCODE.INC                                                ;;

;;                                                              ;;

;;  KolibriOS 16-bit loader,                                    ;;

;;                        based on bootcode for MenuetOS        ;;

;;                                                              ;;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

$Revision: 838 $

;==========================================================================

;

;                           16 BIT FUNCTIONS

;

;==========================================================================

putchar:

; in: al=character

        mov     ah, 0Eh

        mov     bh, 0

        int     10h

        ret

print:

; in: si->string

        mov     al, 186

        call    putchar

        mov     al, ' '

        call    putchar

printplain:

; in: si->string

        pusha

        lodsb

@@:

        call    putchar

        lodsb

        cmp     al, 0

        jnz     @b

        popa

        ret

getkey:

; get number in range [bl,bh] (bl,bh in ['0'..'9'])

; in: bx=range

; out: ax=digit (1..9, 10 for 0)

        mov     ah, 0

        int     16h

        cmp     al, bl

        jb      getkey

        cmp     al, bh

        ja      getkey

        push    ax

        call    putchar

        pop     ax

        and     ax, 0Fh

        jnz     @f

        mov     al, 10

@@:

        ret

setcursor:

; in: dl=column, dh=row

        mov     ah, 2

        mov     bh, 0

        int     10h

        ret

macro _setcursor row,column

{

        mov     dx, row*256 + column

        call    setcursor

}

boot_read_floppy:

        push    si

        xor     si, si

        mov     ah, 2   ; read

@@:

        push    ax

        int     0x13

        pop     ax

        jnc     @f

        inc     si

        cmp     si, 10

        jb      @b

        mov     si, badsect

sayerr_plain:

        call    printplain

        jmp     $

@@:

        pop     si

        ret

; convert abs. sector number (AX) to BIOS T:H:S

; sector number = (abs.sector%BPB_SecPerTrk)+1

; pre.track number = (abs.sector/BPB_SecPerTrk)

; head number = pre.track number%BPB_NumHeads

; track number = pre.track number/BPB_NumHeads

; Return: cl - sector number

;         ch - track number

;         dl - drive number (0 = a:)

;         dh - head number

conv_abs_to_THS:

        push    bx

        mov     bx,word [BPB_SecPerTrk]

        xor     dx,dx

        div     bx

        inc     dx

        mov     cl, dl                          ; cl = sector number

        mov     bx,word [BPB_NumHeads]

        xor     dx,dx

        div     bx

        ; !!!!!!! ax = track number, dx = head number

        mov     ch,al                           ; ch=track number

        xchg    dh,dl                           ; dh=head number

        mov     dl,0                            ; dl=0 (drive 0 (a:))

        pop     bx

        retn

; needed variables

BPB_SecPerTrk   dw      0                       ; sectors per track

BPB_NumHeads    dw      0                       ; number of heads

BPB_FATSz16     dw      0                       ; size of FAT

BPB_RootEntCnt  dw      0                       ; count of root dir. entries

BPB_BytsPerSec  dw      0                       ; bytes per sector

BPB_RsvdSecCnt  dw      0                       ; number of reserved sectors

BPB_TotSec16    dw      0                       ; count of the sectors on the volume

BPB_SecPerClus  db      0                       ; number of sectors per cluster

BPB_NumFATs     db      0                       ; number of FAT tables

abs_sector_adj  dw      0                       ; adjustment to make abs. sector number

end_of_FAT      dw      0                       ; end of FAT table

FirstDataSector dw      0                       ; begin of data

;=========================================================================

;

;                           16 BIT CODE

;

;=========================================================================

include 'bootvesa.inc'                 ;Include source for boot vesa

start_of_code:

        cld

; \begin{diamond}[02.12.2005]

; if bootloader sets ax = 'KL', then ds:si points to loader block

        cmp     ax, 'KL'

        jnz     @f

        mov     word [cs:cfgmanager.loader_block], si

        mov     word [cs:cfgmanager.loader_block+2], ds

@@:

; \end{diamond}[02.12.2005]

; if bootloader sets cx = 'HA' and dx = 'RD', then bx contains identifier of source hard disk

; (see comment to bx_from_load)

        cmp     cx, 'HA'

        jnz     no_hd_load

        cmp     dx,'RD'

        jnz     no_hd_load

        mov     word [cs:bx_from_load], bx              ; {SPraid}[13.03.2007]

no_hd_load:

; set up stack

        mov     ax, 3000h

        mov     ss, ax

        mov     sp, 0EC00h

; set up segment registers

        push    cs

        pop     ds

        push    cs

        pop     es

; set videomode

        mov     ax, 3

        int     0x10

if lang eq ru

 ; Load & set russian VGA font (RU.INC)

        mov     bp, RU_FNT1             ; RU_FNT1 - First part

        mov     bx, 1000h               ; 768 bytes

        mov     cx, 30h                 ; 48 symbols

        mov     dx, 80h                 ; 128 - position of first symbol

        mov     ax, 1100h

        int     10h

        mov     bp, RU_FNT2             ; RU_FNT2 -Second part

        mov     bx, 1000h               ; 512 bytes

        mov     cx, 20h                 ; 32 symbols

        mov     dx, 0E0h                ; 224 - position of first symbol

        mov     ax, 1100h

        int     10h

 ; End set VGA russian font

else if lang eq et

        mov     bp, ET_FNT              ; ET_FNT1

        mov     bx, 1000h               ;

        mov     cx, 255                 ; 256 symbols

        xor     dx, dx                  ; 0 - position of first symbol

        mov     ax, 1100h

        int     10h

end if

; draw frames

        push    0xb800

        pop     es

        xor     di, di

        mov     ah, 1*16+15

; draw top

        mov     si, d80x25_top

        mov     cx, d80x25_top_num * 80

@@:

        lodsb

        stosw

        loop    @b

; draw spaces

        mov     si, space_msg

        mov     dx, 25 - d80x25_top_num - d80x25_bottom_num

dfl1:

        push    si

        mov     cx, 80

@@:

        lodsb

        stosw

        loop    @b

        pop     si

        dec     dx

        jnz     dfl1

; draw bottom

        mov     si, d80x25_bottom

        mov     cx, d80x25_bottom_num * 80

@@:

        lodsb

        stosw

        loop    @b

        mov     byte [space_msg+80], 0    ; now space_msg is null terminated

        _setcursor d80x25_top_num,0

; TEST FOR 386+

           mov     bx, 0x4000

           pushf

           pop     ax

           mov     dx, ax

           xor     ax, bx

           push    ax

           popf

           pushf

           pop     ax

           and     ax, bx

           and     dx, bx

           cmp     ax, dx

           mov     si, not386

           jz      sayerr

           xor   eax, eax

           cpuid

           cmp   eax, 0

           mov   si, sz_nopse

           jbe   sayerr

           mov   eax, 1

           cpuid

           bt    edx, 3

           mov   si, sz_nopse

           jnc   sayerr

           xor ebx, ebx

           mov es, bx

           mov edi, 0x9104

           mov ecx, 20

           mov edx, 0x534D4150

           mov [es:0x9100], ebx

           mov eax, 0xe820

           int 0x15

           mov   si, sz_nosmap

           jc sayerr

           cmp eax, 0x534D4150

           je cpugood

sayerr:

           call    print

           jmp     $

cpugood:

        push    0

        popf

        sti

; set up esp

        movzx   esp, sp

        push    0

        pop     es

        and     word [es:0x9031], 0

; \begin{Mario79}

; find HDD IDE DMA PCI device

; check for PCI BIOS

        mov     ax, 0xB101

        int     0x1A

        jc      .nopci

        cmp     edx, 'PCI '

        jnz     .nopci

; find PCI class code

; class 1 = mass storage

; subclass 1 = IDE controller

; a) class 1, subclass 1, programming interface 0x80

        mov     ax, 0xB103

        mov     ecx, 1*10000h + 1*100h + 0x80

        xor     si, si  ; device index = 0

        int     0x1A

        jnc     .found

; b) class 1, subclass 1, programming interface 0x8A

        mov     ax, 0xB103

        mov     ecx, 1*10000h + 1*100h + 0x8A

        xor     si, si  ; device index = 0

        int     0x1A

        jnc     .found

; c) class 1, subclass 1, programming interface 0x85

        mov     ax, 0xB103

        mov     ecx, 1*10000h + 1*100h + 0x85

        xor     si, si

        int     0x1A

        jc      .nopci

.found:

; get memory base

        mov     ax, 0xB10A

        mov     di, 0x20        ; memory base is config register at 0x20

        int     0x1A

        jc      .nopci

        and     cx, 0xFFF0      ; clear address decode type

        mov     [es:0x9031], cx

.nopci:

; \end{Mario79}

        mov     al, 0xf6        ; Ñáðîñ êëàâèàòóðû, ðàçðåøèòü ñêàíèðîâàíèå

        out     0x60, al

        xor     cx, cx

wait_loop:       ; variant 2

; reading state of port of 8042 controller

        in      al, 64h

        and     al, 00000010b  ; ready flag

; wait until 8042 controller is ready

        loopnz  wait_loop

;;;/diamond today   5.02.2008

; set keyboard typematic rate & delay

        mov     al, 0xf3

        out     0x60, al

        xor     cx, cx

@@:

        in      al, 64h

        test    al, 2

        loopnz  @b

        mov     al, 0

        out     0x60, al

        xor     cx, cx

@@:

        in      al, 64h

        test    al, 2

        loopnz  @b

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; --------------- APM ---------------------

        and     word [es:0x9044], 0     ; ver = 0.0 (APM not found)

        mov     ax, 0x5300

        xor     bx, bx

        int     0x15

        jc      apm_end                 ; APM not found

        test    cx, 2

        jz      apm_end                 ; APM 32-bit protected-mode interface not supported

        mov     [es:0x9044], ax         ; Save APM Version

        mov     [es:0x9046], cx         ; Save APM flags

        ; Write APM ver ----

        and     ax, 0xf0f

        add     ax, '00'

        mov     si, msg_apm

        mov     [si + 5], ah

        mov     [si + 7], al

        _setcursor 0, 3

        call    printplain

        ; ------------------

        mov     ax, 0x5304              ; Disconnect interface

        xor     bx, bx

        int     0x15

        mov     ax, 0x5303              ; Connect 32 bit mode interface

        xor     bx, bx

        int     0x15

        mov     [es:0x9040], ebx

        mov     [es:0x9050], ax

        mov     [es:0x9052], cx

        mov     [es:0x9054], dx

apm_end:

        _setcursor d80x25_top_num, 0

;CHECK current of code

        cmp     [cfgmanager.loader_block], -1

        jz      noloaderblock

        les     bx, [cfgmanager.loader_block]

        cmp     byte [es:bx], 1

        mov     si, loader_block_error

        jnz     sayerr

        push    0

        pop     es

noloaderblock:

; DISPLAY VESA INFORMATION

         call    print_vesa_info

         call    calc_vmodes_table

         call    check_first_parm  ;check and enable cursor_pos

; \begin{diamond}[30.11.2005]

cfgmanager:

; settings:

; a) preboot_graph = graphical mode

;    preboot_gprobe = probe this mode?

; b) preboot_dma  = use DMA access?

; c) preboot_vrrm = use VRR?

; d) preboot_device = from what boot?

; determine default settings

        mov     [.bSettingsChanged], 0

;.preboot_gr_end:

        mov     di, preboot_device

; if image in memory is present and [preboot_device] is uninitialized,

; set it to use this preloaded image

        cmp     byte [di], 0

        jnz     .preboot_device_inited

        cmp     [.loader_block], -1

        jz      @f

        les     bx, [.loader_block]

        test    byte [es:bx+1], 1

        jz      @f

        mov     byte [di], 3

        jmp     .preboot_device_inited

@@:

; otherwise, set [preboot_device] to 1 (default value - boot from floppy)

        mov     byte [di], 1

.preboot_device_inited:

; following 6 lines set variables to 1 if its current value is 0

        cmp     byte [di+preboot_dma-preboot_device], 1

        adc     byte [di+preboot_dma-preboot_device], 0

        cmp     byte [di+preboot_biosdisk-preboot_device], 1

        adc     byte [di+preboot_biosdisk-preboot_device], 0

        cmp     byte [di+preboot_vrrm-preboot_device], 1

        adc     byte [di+preboot_vrrm-preboot_device], 0

; notify user

        _setcursor 5,2

        mov     si, linef

        call    printplain

        mov     si, start_msg

        call    print

        mov     si, time_msg

        call    print

; get start time

        call    .gettime

        mov     [.starttime], eax

        mov     word [.timer], .newtimer

        mov     word [.timer+2], cs

.printcfg:

        _setcursor 9,0

        mov     si, current_cfg_msg

        call    print

        mov     si, curvideo_msg

        call    print

            call    draw_current_vmode

        mov     si, usebd_msg

        cmp     [preboot_biosdisk], 1

        call    .say_on_off

        mov     si, vrrm_msg

        cmp     [preboot_vrrm], 1

        call    .say_on_off

        mov     si, preboot_device_msg

        call    print

        mov     al, [preboot_device]

        and     eax, 7

        mov     si, [preboot_device_msgs+eax*2]

        call    printplain

.show_remarks:

; show remarks in gray color

        mov     di, ((21-num_remarks)*80 + 2)*2

        push    0xB800

        pop     es

        mov     cx, num_remarks

        mov     si, remarks

.write_remarks:

        lodsw

        push    si

        xchg    ax, si

        mov     ah, 1*16+7      ; background: blue (1), foreground: gray (7)

        push    di

.write_remark:

        lodsb

        test    al, al

        jz      @f

        stosw

        jmp     .write_remark

@@:

        pop     di

        pop     si

        add     di, 80*2

        loop    .write_remarks

.wait:

        _setcursor 25,0         ; out of screen

; set timer interrupt handler

        cli

        push    0

        pop     es

        push    dword [es:8*4]

        pop     dword [.oldtimer]

        push    dword [.timer]

        pop     dword [es:8*4]

;        mov     eax, [es:8*4]

;        mov     [.oldtimer], eax

;        mov     eax, [.timer]

;        mov     [es:8*4], eax

        sti

; wait for keypressed

        xor     ax,ax

        int     16h

        push    ax

; restore timer interrupt

;        push    0

;        pop     es

        mov     eax, [.oldtimer]

        mov     [es:8*4], eax

        mov     [.timer], eax

        _setcursor 7,0

        mov     si, space_msg

        call    printplain

; clear remarks and restore normal attributes

        push    es

        mov     di, ((21-num_remarks)*80 + 2)*2

        push    0xB800

        pop     es

        mov     cx, num_remarks

        mov     ax, ' ' + (1*16 + 15)*100h

@@:

        push    cx

        mov     cx, 76

        rep     stosw

        pop     cx

        add     di, 4*2

        loop    @b

        pop     es

        pop     ax

; switch on key

        cmp     al, 13

        jz      .continue

        or      al, 20h

        cmp     al, 'a'

        jz      .change_a

        cmp     al, 'b'

        jz      .change_b

        cmp     al, 'c'

        jz      .change_c

        cmp     al, 'd'

        jnz     .show_remarks

        _setcursor 15,0

        mov     si, bdev

        call    print

        mov     bx, '14'

        call    getkey

        mov     [preboot_device], al

        _setcursor 13,0

.d:

        mov     [.bSettingsChanged], 1

        call    clear_vmodes_table             ;clear vmodes_table

        jmp    .printcfg

.change_a:

.loops:

        call    draw_vmodes_table

        _setcursor 25,0         ; out of screen

        xor     ax,ax

        int     0x16

;        call    clear_table_cursor             ;clear current position of cursor

        mov     si,word [cursor_pos]

        cmp     ah,0x48;x,0x48E0               ; up

        jne     .down

        cmp     si,modes_table

        jbe     .loops

        sub     word [cursor_pos],size_of_step

        jmp     .loops

.down:  cmp     ah,0x50;x,0x50E0               ; down

        jne     .pgup

        cmp     word[es:si+10],-1

        je      .loops

        add     word [cursor_pos],size_of_step

        jmp     .loops

.pgup:  cmp     ah,0x49                 ; page up

        jne     .pgdn

        sub     si, size_of_step*long_v_table

        cmp     si, modes_table

        jae     @f

        mov     si, modes_table

@@:

        mov     word [cursor_pos], si

        mov     si, word [home_cursor]

        sub     si, size_of_step*long_v_table

        cmp     si, modes_table

        jae     @f

        mov     si, modes_table

@@:

        mov     word [home_cursor], si

        jmp     .loops

.pgdn:  cmp     ah,0x51                 ; page down

        jne     .enter

        mov     ax, [end_cursor]

        add     si, size_of_step*long_v_table

        cmp     si, ax

        jb      @f

        mov     si, ax

        sub     si, size_of_step

@@:

        mov     word [cursor_pos], si

        mov     si, word [home_cursor]

        sub     ax, size_of_step*long_v_table

        add     si, size_of_step*long_v_table

        cmp     si, ax

        jb      @f

        mov     si, ax

@@:

        mov     word [home_cursor], si

        jmp     .loops

.enter: cmp     al,0x0D;x,0x1C0D               ; enter

        jne     .loops

        push    word [cursor_pos]

        pop     bp

        push    word [es:bp]

        pop     word [x_save]

        push    word [es:bp+2]

        pop     word [y_save]

        push    word [es:bp+6]

        pop     word [number_vm]

        mov     word [preboot_graph],bp           ;save choose

        jmp    .d

.change_b:

        _setcursor 15,0

;        mov     si, ask_dma

;        call    print

;        mov     bx, '13'

;        call    getkey

;        mov     [preboot_dma], al

        mov     si, ask_bd

        call    print

        mov     bx, '12'

        call    getkey

        mov     [preboot_biosdisk], al

        _setcursor 11,0

        jmp     .d

.change_c:

        _setcursor 15,0

        mov     si, vrrmprint

        call    print

        mov     bx, '12'

        call    getkey

        mov     [preboot_vrrm], al

        _setcursor 12,0

        jmp     .d

;;;;;;;;;;;;;;;;;;;;;;;;;;;;

.say_on_off:

        pushf

        call    print

        mov     si, on_msg

        popf

        jz      @f

        mov     si, off_msg

@@:     jmp     printplain

; novesa and vervesa strings are not used at the moment of executing this code

virtual at novesa

.oldtimer dd ?

.starttime dd ?

.bSettingsChanged db ?

.timer dd ?

end virtual

.loader_block dd -1

.gettime:

        mov     ah, 0

        int     1Ah

        xchg    ax, cx

        shl     eax, 10h

        xchg    ax, dx

        ret

.newtimer:

        push    ds

        push    cs

        pop     ds

        pushf

        call    [.oldtimer]

        pushad

        call    .gettime

        sub     eax, [.starttime]

        sub     ax, 18*5

        jae     .timergo

        neg     ax

        add     ax, 18-1

        mov     bx, 18

        xor     dx, dx

        div     bx

if lang eq ru

; ¯®¤®¦¤¨â¥ 5 ᥪ㭤, 4/3/2 ᥪ㭤ë, 1 ᥪ㭤ã

        cmp     al, 5

        mov     cl, ' '

        jae     @f

        cmp     al, 1

        mov     cl, 'ã'

        jz      @f

        mov     cl, 'ë'

@@:     mov     [time_str+9], cl

else if lang eq et

        cmp     al, 1

        ja      @f

        mov     [time_str+9], ' '

        mov     [time_str+10],' '

@@:

else

; wait 5/4/3/2 seconds, 1 second

        cmp     al, 1

        mov     cl, 's'

        ja      @f

        mov     cl, ' '

@@:     mov     [time_str+9], cl

end if

        add     al, '0'

        mov     [time_str+1], al

        mov     si, time_msg

        _setcursor 7,0

        call    print

        _setcursor 25,0

        popad

        pop     ds

        iret

.timergo:

        push    0

        pop     es

        mov     eax, [.oldtimer]

        mov     [es:8*4], eax

        mov     sp, 0EC00h

.continue:

        sti

        _setcursor 6,0

        mov     si, space_msg

        call    printplain

        call    printplain

        _setcursor 6,0

        mov     si, loading_msg

        call    print

        _setcursor 15,0

        cmp     [.bSettingsChanged], 0

        jz      .load

        cmp     [.loader_block], -1

        jz      .load

        les     bx, [.loader_block]

        mov     eax, [es:bx+3]

        push    ds

        pop     es

        test    eax, eax

        jz      .load

        push    eax

        mov     si, save_quest

        call    print

.waityn:

        mov     ah, 0

        int     16h

        or      al, 20h

        cmp     al, 'n'

        jz      .loadc

        cmp     al, 'y'

        jnz     .waityn

        call    putchar

        mov     byte [space_msg+80], 186

        pop     eax

        push    cs

        push    .cont

        push    eax

        retf

.loadc:

        pop     eax

.cont:

        push    cs

        pop     ds

        mov     si, space_msg

        mov     byte [si+80], 0

        _setcursor 15,0

        call    printplain

        _setcursor 15,0

.load:

; \end{diamond}[02.12.2005]

; ASK GRAPHICS MODE

        call    set_vmode

; GRAPHICS ACCELERATION

; force yes

        mov     [es:0x901C], byte 1

; DMA ACCESS TO HD

        mov     al, [preboot_dma]

        mov     [es:0x901F], al

; VRR_M USE

        mov     al,[preboot_vrrm]

        mov     [es:0x9030], al

        mov     [es:0x901E], byte 1

; BOOT DEVICE

        mov     al, [preboot_device]

        dec     al

        mov     [boot_dev], al

; READ DISKETTE TO MEMORY

;        cmp     [boot_dev],0

        jne     no_sys_on_floppy

        mov     si,diskload

        call    print

        xor     ax, ax            ; reset drive

        xor     dx, dx

        int     0x13

; do we boot from CD-ROM?

        mov     ah, 41h

        mov     bx, 55AAh

        xor     dx, dx

        int     0x13

        jc      .nocd

        cmp     bx, 0AA55h

        jnz     .nocd

        mov     ah, 48h

        push    ds

        push    es

        pop     ds

        mov     si, 0xa000

        mov     word [si], 30

        int     0x13

        pop     ds

        jc      .nocd

        push    ds

        lds     si, [es:si+26]

        test    byte [ds:si+10], 40h

        pop     ds

        jz      .nocd

; yes - read all floppy by 18 sectors

; TODO: !!!! read only first sector and set variables !!!!!

; ...

; TODO: !!! then read flippy image track by track

        mov     cx, 0x0001      ; startcyl,startsector

.a1:

        push    cx dx

        mov     al, 18

        mov     bx, 0xa000

        call    boot_read_floppy

        mov     si, movedesc

        push    es

        push    ds

        pop     es

        mov     cx, 256*18

        mov     ah, 0x87

        int     0x15

        pop     es

        pop     dx cx

        test    ah, ah

        jnz     sayerr_floppy

        add     dword [si+8*3+2], 512*18

        inc     dh

        cmp     dh, 2

        jnz     .a1

        mov     dh, 0

        inc     ch

        cmp     ch, 80

        jae     ok_sys_on_floppy

        pusha

        mov     al, ch

        shr     ch, 2

        add     al, ch

        aam

        xchg    al, ah

        add     ax, '00'

        mov     si, pros

        mov     [si], ax

        call    printplain

        popa

        jmp     .a1

.nocd:

; no - read only used sectors from floppy

; now load floppy image to memory

; at first load boot sector and first FAT table

; read only first sector and fill variables

        mov     cx, 0x0001      ; first logical sector

        xor     dx, dx          ; head = 0, drive = 0 (a:)

        mov     al, 1           ; read one sector

        mov     bx, 0xB000      ; es:bx -> data area

        call    boot_read_floppy

; fill the necessary parameters to work with a floppy

        mov     ax, word [es:bx+24]

        mov     word [BPB_SecPerTrk], ax

        mov     ax, word [es:bx+26]

        mov     word [BPB_NumHeads], ax

        mov     ax, word [es:bx+22]

        mov     word [BPB_FATSz16], ax

        mov     ax, word [es:bx+17]

        mov     word [BPB_RootEntCnt], ax

        mov     ax, word [es:bx+11]

        mov     word [BPB_BytsPerSec], ax

        mov     ax, word [es:bx+14]

        mov     word [BPB_RsvdSecCnt], ax

        mov     ax, word [es:bx+19]

        mov     word [BPB_TotSec16], ax

        mov     al, byte [es:bx+13]

        mov     byte [BPB_SecPerClus], al

        mov     al, byte [es:bx+16]

        mov     byte [BPB_NumFATs], al

; count of clusters in FAT12 ((size_of_FAT*2)/3)

        mov     ax, word [BPB_FATSz16]

        mov     cx, word [BPB_BytsPerSec]

        xor     dx, dx

        mul     cx

        shl     ax, 1

        mov     cx, 3

        div     cx              ; now ax - number of clusters in FAT12

        mov     word [end_of_FAT], ax

; load first FAT table

        mov     cx, 0x0002      ; startcyl,startsector          ; TODO!!!!!

        xor     dx, dx          ; starthead,drive

        mov     al, byte [BPB_FATSz16]     ; no of sectors to read

        add     bx, word [BPB_BytsPerSec]  ; es:bx -> data area

        call    boot_read_floppy

        mov     bx, 0xB000

; and copy them to extended memory

        mov     si, movedesc

        mov     [si+8*2+3], bh          ; from

        mov     ax, word [BPB_BytsPerSec]

        shr     ax, 1                   ; words per sector

        mov     cx, word [BPB_RsvdSecCnt]

        add     cx, word [BPB_FATSz16]

        mul     cx

        push    ax                      ; save to stack count of words in boot+FAT

        xchg    ax, cx

        push    es

        push    ds

        pop     es

        mov     ah, 0x87

        int     0x15

        pop     es

        test    ah, ah

        jz      @f

sayerr_floppy:

        mov     dx, 0x3f2

        mov     al, 0

        out     dx, al

        mov     si, memmovefailed

        jmp     sayerr_plain

@@:

        pop     ax                      ; restore from stack count of words in boot+FAT

        shl     ax, 1                   ; make bytes count from count of words

        and     eax, 0ffffh

        add     dword [si+8*3+2], eax

; copy first FAT to second copy

; TODO: BPB_NumFATs !!!!!

        add     bx, word [BPB_BytsPerSec]       ; !!! TODO: may be need multiply by BPB_RsvdSecCnt !!!

        mov     byte [si+8*2+3], bh     ; bx - begin of FAT

        mov     ax, word [BPB_BytsPerSec]

        shr     ax, 1                   ; words per sector

        mov     cx, word [BPB_FATSz16]

        mul     cx

        mov     cx, ax                  ; cx - count of words in FAT

        push    es

        push    ds

        pop     es

        mov     ah, 0x87

        int     0x15

        pop     es

        test    ah, ah

        jnz     sayerr_floppy

        mov     ax, cx

        shl     ax, 1

        and     eax, 0ffffh             ; ax - count of bytes in FAT

        add     dword [si+8*3+2], eax

; reading RootDir

; TODO: BPB_NumFATs

        add     bx, ax

        add     bx, 100h

        and     bx, 0ff00h                      ; bx - place in buffer to write RootDir

        push    bx

        mov     bx, word [BPB_BytsPerSec]

        shr     bx, 5                           ; divide bx by 32

        mov     ax, word [BPB_RootEntCnt]

        xor     dx, dx

        div     bx

        push    ax                              ; ax - count of RootDir sectors

        mov     ax, word [BPB_FATSz16]

        xor     cx, cx

        mov     cl, byte [BPB_NumFATs]

        mul     cx

        add     ax, word [BPB_RsvdSecCnt]       ; ax - first sector of RootDir

        mov     word [FirstDataSector], ax

        pop     bx

        push    bx

        add     word [FirstDataSector], bx      ; Begin of data region of floppy

; read RootDir

        call    conv_abs_to_THS

        pop     ax

        pop     bx                              ; place in buffer to write

        push    ax

        call    boot_read_floppy                ; read RootDir into buffer

; copy RootDir

        mov     byte [si+8*2+3], bh             ; from buffer

        pop     ax                              ; ax = count of RootDir sectors

        mov     cx, word [BPB_BytsPerSec]

        mul     cx

        shr     ax, 1

        mov     cx, ax                          ; count of words to copy

        push    es

        push    ds

        pop     es

        mov     ah, 0x87

        int     0x15

        pop     es

        mov     ax, cx

        shl     ax, 1

        and     eax, 0ffffh             ; ax - count of bytes in RootDir

        add     dword [si+8*3+2], eax   ; add count of bytes copied

; Reading data clusters from floppy

        mov     byte [si+8*2+3], bh

        push    bx

        mov     di, 2                   ; First data cluster

.read_loop:

        mov     bx, di

        shr     bx, 1                   ; bx+di = di*1.5