mirror of
https://github.com/vxunderground/MalwareSourceCode
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216 lines
7.0 KiB
NASM
216 lines
7.0 KiB
NASM
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; ATTR.ASM -- File Attribute Utility
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; ==================================
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CSEG Segment
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Assume CS:CSEG, DS:CSEG, ES:CSEG, SS:CSEG
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Org 0080h
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Parameter Label Byte ; Parameter is here
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Org 0100h
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Entry: Jmp Begin ; Entry Point
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; Most Data (some more at end of program)
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; ---------------------------------------
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db "ATTR (C) 1986, Ziff-Davis Publishing Co.",1Ah
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db " Programmed by Charles Petzold ",1Ah
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SyntaxMsg db "Syntax: ATTR [+A|-A] [+S|-S] [+H|-H] [+R|-R] "
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db "[drive:][path]filename",13,10
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db " Archive System Hidden Read-Only$"
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DosVersMsg db "ATTR: Needs DOS 2.0 +$"
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FlagErrMsg db "ATTR: Incorrect flag$"
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FileSpecMsg db "ATTR: Incorrect File Spec$"
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Delimiters db 9,' ,;=',13
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FlagList db "ASHR", 20h, 04h, 02h, 01h
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AllFlagList db " $Arc $Dir $$$$$$Sys $Hid $R-O$"
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ChangeFlag db 0
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AndAttrBits db 0
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OrAttrBits db 0
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SearchString dw ?
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AppendFileName dw ?
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; Check DOS Version
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; -----------------
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Begin: Mov AH, 30h ; Check for DOS Version
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Int 21h ; through DOS call
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Cmp AL, 2 ; See if it's 2.0 or above
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Jae DosVersOK ; If so, continue
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Mov DX, Offset DosVersMsg ; Error message
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ErrorExit: Mov AH, 9 ; Print String function call
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Int 21h ; Do it
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Int 20h ; And exit prematurely
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; Parse Command Line to get file specification
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; --------------------------------------------
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DosVersOK: Mov SI, 1+Offset Parameter ; Parameter string pointer
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Cld ; Directions forward
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FlagSearch: Lodsb ; Get Byte
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Mov DI, Offset Delimiters ; Check if delimiter
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Mov CX, 5 ; Five delimiters to check
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Repne Scasb ; Scan the string
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Je FlagSearch ; If delimiter, circle back
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Mov DX, Offset SyntaxMsg ; Possible error msg
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Cmp AL, 13 ; If carriage return, no file
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Je ErrorExit ; so exit with message
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Mov DI, Offset OrAttrBits ; Pointer to plus flag saver
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Cmp AL, '+' ; See if plus sign
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Je PlusOrMinus ; If so, save the bit
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Mov DI, Offset AndAttrBits ; Pointer to minus flag saver
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Cmp AL, '-' ; See if minus sign
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Jne MustBeFile ; If not, it must be file name
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PlusOrMinus: Mov [ChangeFlag],-1 ; Set for changing
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Lodsb ; Get the next byte
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And AL, 0DFh ; Capitalize it
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Mov BX, Offset FlagList ; List for scanning
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Mov CX, 4 ; Scan for A, S, H, and R
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SearchList: Cmp AL, [BX] ; See if a match
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Jz FoundFlag ; If so, proceed to save
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Inc BX ; Kick up pointer
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Loop SearchList ; And loop around for next
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Mov DX, Offset FlagErrMsg ; Otherwise, set message
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Jmp ErrorExit ; And terminate
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FoundFlag: Mov AL, [BX + 4] ; Get bit mask
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Or [DI], AL ; Turn saved bit on
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Jmp FlagSearch ; And continue looking
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MustBeFile: Not [AndAttrBits] ; Invert bits for turn off
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Mov [SearchString], SI ; Save file name pointer
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Dec [SearchString] ; Actually one byte lower
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EndSearch: Lodsb ; Get Byte
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Mov DI, Offset Delimiters ; Check if delimiter
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Mov CX, 6 ; Six delimiters including CR
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Repne Scasb ; Scan the string
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Jne EndSearch ; If not delimiter, keep going
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; Transfer Search String down at end of program
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; ---------------------------------------------
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Dec SI ; Points after file spec
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Mov Byte Ptr [SI], 0 ; Make it ASCIIZ string
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Mov CX, SI ; CX points to end
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Mov SI, [SearchString] ; SI points to beginning
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Sub CX, SI ; Now CX is length of it
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Mov DI, Offset PathAndFile ; Destination of string
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Mov [AppendFileName], DI ; Save it here also
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SearchTrans: Lodsb ; Get byte of search string
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Stosb ; And save it down below
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Cmp AL, ':' ; See if drive marker
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Je PossibleEnd ; If so, take note of it
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Cmp AL, '\' ; See if path separator
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Jne NextCharacter ; If not, skip next code
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PossibleEnd: Mov [AppendFileName], DI ; This is the new end
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NextCharacter: Loop SearchTrans ; Do it again until done
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; Find Files from Search String
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; -----------------------------
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Mov DX, Offset DTABuffer ; Set File Find buffer
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Mov AH, 1Ah ; by calling DOS
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Int 21h
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Mov DX, [SearchString] ; Search string
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Mov CX, 16h ; Search Everything
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Mov AH, 4Eh ; Find first file
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FindFile: Int 21h ; Call DOS to find file
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Jnc Continue ; If no error continue
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Cmp AX, 18 ; If not "no more files" error
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Jnz FindError ; print error message
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Jmp NoMoreFiles ; Now get out of the loop
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FindError: Mov DX, Offset FileSpecMsg ; Error message for file spec
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Jmp ErrorExit ; Exit and print message
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Continue: Mov SI, 30+Offset DTABuffer ; Points to filename
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Cmp Byte Ptr [SI], '.' ; See if "dot" entry
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Jnz FileIsOK ; If not, continue
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Jmp FindNextFile ; If so, skip it
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FileIsOK: Mov DI, [AppendFileName] ; Destination of file name
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Mov CX, 14 ; Number of bytes to display
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TransferName: Lodsb ; Get the byte in file name
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Stosb ; Save it
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Or AL, AL ; See if terminating zero
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Jz PadWithBlanks ; If so, display blanks
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Call DisplayChar ; Display the character
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Loop TransferName ; And loop back around
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PadWithBlanks: Mov AL, ' ' ; Pad names with blanks
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Call DisplayChar
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Loop PadWithBlanks ; And loop until CX is zero
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; Change And Display File Attributes
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; ----------------------------------
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Mov DX, Offset PathAndFile ; Points to ASCIIZ string
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Test [ChangeFlag], -1 ; See if changing attributes
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Jz DisplayIt ; If not, just display them
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Mov AX, 4300h ; Get file attribute
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Int 21h ; by calling DOS
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And CL, 27h ; Zero out some bits
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And CL, [AndAttrBits] ; Turn off some bits
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Or CL, [OrAttrBits] ; Turn on some bits
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Mov AX, 4301h ; Set file attribute
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Int 21h ; by calling DOS
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DisplayIt: Mov AX, 4300h ; Get file attribute
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Int 21h ; by calling DOS
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Mov BL, CL ; BL is attributes
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Or BL, 08h ; Turn on Volume bit
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Shl BL, 1 ; Shift to get rid of
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Shl BL, 1 ; unused bits
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Mov CX, 6 ; Number of bits left
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Mov DX, 5+Offset AllFlagList; Storage of abbreviations
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AttrListLoop: Push DX ; Save abbreviation pointer
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Shl BL, 1 ; Shift bit into carry
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Jc FlagIsOn ; See if it's on
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Mov DX, Offset AllFlagList ; If not, print blanks
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FlagIsOn: Mov AH, 9 ; Print string
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Int 21h ; by calling DOS
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Pop DX ; Get back abbreviation ptr
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Add DX, 5 ; Kick up for next bit
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Loop AttrListLoop ; And loop around
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Mov AL, 13 ; Print carriage return
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Call DisplayChar
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Mov AL, 10 ; Print line feed
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Call DisplayChar
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FindNextFile: Mov AH, 4Fh ; Find next file
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Jmp FindFile ; By looping around
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NoMoreFiles: Int 20h ; Terminate
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; SUBROUTINE: Display Character in AL
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; -----------------------------------
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DisplayChar: Push AX
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Push DX
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Mov DL, AL ; Move character to DL
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Mov AH, 2 ; Display it
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Int 21h ; by calling DOS
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Pop DX
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Pop AX
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Ret
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; Some data stored at end to cut down COM size
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; --------------------------------------------
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DTABuffer Label Byte ; For file find calls
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PathAndFile equ DTABuffer + 43 ; For file path and name
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CSEG EndS ; End of the segment
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End Entry ; Denotes entry point
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