Now correctly loads FAT12 from floppies of any volume into ramdisk, rather than only from 1.44 MB
git-svn-id: svn://kolibrios.org@795 a494cfbc-eb01-0410-851d-a64ba20cac60
This commit is contained in:
Dmitry Kartashov (shurf)
parent
16b20de954
commit
8ca0210b13
@ -99,6 +99,45 @@ sayerr_plain:
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pop si
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ret
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; convert abs. sector number (AX) to BIOS T:H:S
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; sector number = (abs.sector%BPB_SecPerTrk)+1
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; pre.track number = (abs.sector/BPB_SecPerTrk)
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; head number = pre.track number%BPB_NumHeads
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; track number = pre.track number/BPB_NumHeads
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; Return: cl - sector number
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; ch - track number
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; dl - drive number (0 = a:)
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; dh - head number
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conv_abs_to_THS:
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push bx
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mov bx,word [BPB_SecPerTrk]
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xor dx,dx
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div bx
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inc dx
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mov cl, dl ; cl = sector number
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mov bx,word [BPB_NumHeads]
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xor dx,dx
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div bx
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; !!!!!!! ax = track number, dx = head number
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mov ch,al ; ch=track number
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xchg dh,dl ; dh=head number
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mov dl,0 ; dl=0 (drive 0 (a:))
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pop bx
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retn
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; needed variables
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BPB_SecPerTrk dw 0 ; sectors per track
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BPB_NumHeads dw 0 ; number of heads
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BPB_FATSz16 dw 0 ; size of FAT
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BPB_RootEntCnt dw 0 ; count of root dir. entries
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BPB_BytsPerSec dw 0 ; bytes per sector
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BPB_RsvdSecCnt dw 0 ; number of reserved sectors
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BPB_TotSec16 dw 0 ; count of the sectors on the volume
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BPB_SecPerClus db 0 ; number of sectors per cluster
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BPB_NumFATs db 0 ; number of FAT tables
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abs_sector_adj dw 0 ; adjustment to make abs. sector number
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end_of_FAT dw 0 ; end of FAT table
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FirstDataSector dw 0 ; begin of data
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;=========================================================================
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;
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; 16 BIT CODE
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@ -803,7 +842,12 @@ end if
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pop ds
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jz .nocd
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; yes - read all floppy by 18 sectors
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mov cx, 0x0001 ; startcyl,startsector
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; TODO: !!!! read only first sector and set variables !!!!!
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; ...
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; TODO: !!! then read flippy image track by track
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mov cx, 0x0001 ; startcyl,startsector
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.a1:
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push cx dx
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mov al, 18
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@ -844,20 +888,68 @@ end if
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; no - read only used sectors from floppy
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; now load floppy image to memory
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; at first load boot sector and first FAT table
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mov cx, 0x0001 ; startcyl,startsector
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; read only first sector and fill variables
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mov cx, 0x0001 ; first logical sector
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xor dx, dx ; head = 0, drive = 0 (a:)
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mov al, 1 ; read one sector
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mov bx, 0xB000 ; es:bx -> data area
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call boot_read_floppy
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; fill the necessary parameters to work with a floppy
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mov ax, word [es:bx+24]
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mov word [BPB_SecPerTrk], ax
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mov ax, word [es:bx+26]
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mov word [BPB_NumHeads], ax
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mov ax, word [es:bx+22]
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mov word [BPB_FATSz16], ax
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mov ax, word [es:bx+17]
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mov word [BPB_RootEntCnt], ax
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mov ax, word [es:bx+11]
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mov word [BPB_BytsPerSec], ax
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mov ax, word [es:bx+14]
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mov word [BPB_RsvdSecCnt], ax
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mov ax, word [es:bx+19]
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mov word [BPB_TotSec16], ax
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mov al, byte [es:bx+13]
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mov byte [BPB_SecPerClus], al
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mov al, byte [es:bx+16]
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mov byte [BPB_NumFATs], al
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; count of clusters in FAT12 ((size_of_FAT*2)/3)
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mov ax, word [BPB_FATSz16]
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mov cx, word [BPB_BytsPerSec]
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xor dx, dx
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mul cx
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shl ax, 1
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mov cx, 3
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div cx ; now ax - number of clusters in FAT12
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mov word [end_of_FAT], ax
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; load first FAT table
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mov cx, 0x0002 ; startcyl,startsector ; TODO!!!!!
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xor dx, dx ; starthead,drive
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mov al, 1+9 ; no of sectors to read
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mov bx, 0xB000 ; es:bx -> data area
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mov al, byte [BPB_FATSz16] ; no of sectors to read
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add bx, word [BPB_BytsPerSec] ; es:bx -> data area
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call boot_read_floppy
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mov bx, 0xB000
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; and copy them to extended memory
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mov si, movedesc
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mov [si+8*2+3], bh
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mov [si+8*2+3], bh ; from
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mov ax, word [BPB_BytsPerSec]
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shr ax, 1 ; words per sector
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mov cx, word [BPB_RsvdSecCnt]
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add cx, word [BPB_FATSz16]
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mul cx
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push ax ; save to stack count of words in boot+FAT
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xchg ax, cx
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push es
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push ds
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pop es
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mov cx, 256*10
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mov ah, 0x87
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int 0x15
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pop es
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test ah, ah
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jz @f
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sayerr_floppy:
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@ -867,89 +959,153 @@ sayerr_floppy:
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mov si, memmovefailed
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jmp sayerr_plain
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@@:
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add dword [si+8*3+2], 512*10
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; copy FAT to second copy
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mov byte [si+8*2+3], 0xB2
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mov cx, 256*9
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pop ax ; restore from stack count of words in boot+FAT
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shl ax, 1 ; make bytes count from count of words
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and eax, 0ffffh
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add dword [si+8*3+2], eax
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; copy first FAT to second copy
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; TODO: BPB_NumFATs !!!!!
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add bx, word [BPB_BytsPerSec] ; !!! TODO: may be need multiply by BPB_RsvdSecCnt !!!
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mov byte [si+8*2+3], bh ; bx - begin of FAT
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mov ax, word [BPB_BytsPerSec]
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shr ax, 1 ; words per sector
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mov cx, word [BPB_FATSz16]
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mul cx
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mov cx, ax ; cx - count of words in FAT
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push es
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push ds
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pop es
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mov ah, 0x87
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int 0x15
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pop es
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test ah, ah
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jnz sayerr_floppy
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add dword [si+8*3+2], 512*9
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; calculate total number of sectors to read
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mov ax, 1+9+14 ; boot+FAT+root
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mov di, 0xB203
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.calc_loop:
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test word [es:di], 0xFFF
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jz @f
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inc ax
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@@:
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test word [es:di+1], 0xFFF0
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jz @f
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inc ax
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@@:
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add di, 3
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cmp di, 0xB200+1440*3
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jb .calc_loop
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push ax
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mov bp, 1+9 ; already read sectors
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; now read rest
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mov byte [si+8*2+3], 0xA0
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mov di, 2-14 ; absolute sector-31
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mov cx, 0x0002 ; cylinder=0, sector=2
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mov dx, 0x0100 ; head=1, disk=0
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mov ax, cx
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shl ax, 1
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and eax, 0ffffh ; ax - count of bytes in FAT
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add dword [si+8*3+2], eax
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; reading RootDir
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; TODO: BPB_NumFATs
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add bx, ax
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add bx, 100h
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and bx, 0ff00h ; bx - place in buffer to write RootDir
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push bx
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mov bx, word [BPB_BytsPerSec]
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shr bx, 5 ; divide bx by 32
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mov ax, word [BPB_RootEntCnt]
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xor dx, dx
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div bx
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push ax ; ax - count of RootDir sectors
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mov ax, word [BPB_FATSz16]
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xor cx, cx
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mov cl, byte [BPB_NumFATs]
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mul cx
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add ax, word [BPB_RsvdSecCnt] ; ax - first sector of RootDir
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mov word [FirstDataSector], ax
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pop bx
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push bx
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add word [FirstDataSector], bx ; Begin of data region of floppy
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; read RootDir
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call conv_abs_to_THS
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pop ax
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pop bx ; place in buffer to write
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push ax
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call boot_read_floppy ; read RootDir into buffer
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; copy RootDir
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mov byte [si+8*2+3], bh ; from buffer
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pop ax ; ax = count of RootDir sectors
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mov cx, word [BPB_BytsPerSec]
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mul cx
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shr ax, 1
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mov cx, ax ; count of words to copy
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push es
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push ds
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pop es
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mov ah, 0x87
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int 0x15
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pop es
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mov ax, cx
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shl ax, 1
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and eax, 0ffffh ; ax - count of bytes in RootDir
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add dword [si+8*3+2], eax ; add count of bytes copied
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; Reading data clusters from floppy
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mov byte [si+8*2+3], bh
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push bx
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mov di, 2 ; First data cluster
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.read_loop:
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; determine whether sector must be read
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cmp di, 2
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jl .read
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mov bx, di
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shr bx, 1
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jnc .even
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test word [es:bx+di+0xB200], 0xFFF0
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jmp @f
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mov bx, di
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shr bx, 1 ; bx+di = di*1.5
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jnc .even
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test word [es:bx+di+0xB200], 0xFFF0 ; TODO: may not be 0xB200 !!!
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jmp @f
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.even:
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test word [es:bx+di+0xB200], 0xFFF
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test word [es:bx+di+0xB200], 0xFFF ; TODO: may not be 0xB200 !!!
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@@:
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jz .skip
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.read:
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mov bx, 0xA000
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mov al, 1 ; 1 sector
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call boot_read_floppy
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inc bp
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jz .skip
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; read cluster di
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;.read:
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;conv cluster di to abs. sector ax
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; ax = (N-2) * BPB_SecPerClus + FirstDataSector
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mov ax, di
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sub ax, 2
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xor bx, bx
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mov bl, byte [BPB_SecPerClus]
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mul bx
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add ax, word [FirstDataSector]
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call conv_abs_to_THS
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pop bx
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push bx
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mov al, byte [BPB_SecPerClus] ; number of sectors in cluster
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call boot_read_floppy
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push es
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push ds
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pop es
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pusha
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mov cx, 256
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mov ah, 0x87
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int 0x15
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;
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mov ax, word [BPB_BytsPerSec]
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xor cx, cx
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mov cl, byte [BPB_SecPerClus]
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mul cx
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shr ax, 1 ; ax = (BPB_BytsPerSec * BPB_SecPerClus)/2
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mov cx, ax ; number of words to copy (count words in cluster)
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;
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mov ah, 0x87
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int 0x15 ; copy data
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test ah, ah
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popa
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pop es
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jnz sayerr_floppy
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; skip cluster di
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.skip:
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add dword [si+8*3+2], 512
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inc cx
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cmp cl, 19
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jnz @f
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mov cl, 1
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inc dh
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cmp dh, 2
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jnz @f
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mov dh, 0
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inc ch
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@@:
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pop ax
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push ax
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mov ax, word [BPB_BytsPerSec]
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xor cx, cx
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mov cl, byte [BPB_SecPerClus]
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mul cx
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and eax, 0ffffh ; ax - count of bytes in cluster
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add dword [si+8*3+2], eax
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mov ax, word [end_of_FAT] ; max cluster number
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pusha
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; draw percentage
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; total sectors: ax
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; read sectors: bp
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xchg ax, bp
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; total clusters: ax
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; read clusters: di
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xchg ax, di
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mov cx, 100
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mul cx
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div bp
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div di
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aam
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xchg al, ah
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add ax, '00'
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@ -961,76 +1117,9 @@ sayerr_floppy:
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@@:
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popa
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inc di
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cmp di, 2880-31
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cmp di, word [end_of_FAT] ; max number of cluster
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jnz .read_loop
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; mov cx, 0x0001 ; startcyl,startsector
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; xor dx, dx ; starthead,drive
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; push word 80*2 ; read no of sect
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; reads:
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; pusha
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; xor si,si
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; newread:
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; mov bx,0xa000 ; es:bx -> data area
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; mov ax,0x0200+18 ; read, no of sectors to read
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; int 0x13
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; test ah, ah
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; jz goodread
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; inc si
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; cmp si,10
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; jnz newread
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; mov si,badsect-0x10000
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;sayerr_plain:
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; call printplain
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; jmp $
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; goodread:
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; ; move -> 1mb
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; mov si,movedesc-0x10000
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; push es
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; push ds
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; pop es
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; mov cx,256*18
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; mov ah,0x87
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; int 0x15
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; pop es
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;
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; test ah,ah ; was the move successfull ?
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; je goodmove
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; mov dx,0x3f2 ; floppy motor off
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; mov al,0
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; out dx,al
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; mov si,memmovefailed-0x10000
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; jmp sayerr_plain
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; goodmove:
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;
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; add dword [movedesc-0x10000+0x18+2], 512*18
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; popa
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; inc dh
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; cmp dh,2
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; jnz bb2
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; mov dh,0
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; inc ch
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; pusha ; print prosentage
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; mov si,pros-0x10000
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; shr ch, 2
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; mov al, '5'
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; test ch, 1
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; jnz @f
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; mov al, '0'
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;@@:
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; mov [si+1], al
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; shr ch, 1
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; add ch, '0'
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; mov [si], ch
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; call printplain
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; popa
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; bb2:
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; pop ax
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; dec ax
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; push ax
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; jnz reads
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; readdone:
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; pop ax
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pop bx ; clear stack
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ok_sys_on_floppy:
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mov si, backspace2
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