Source Code 1992 March

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Assembly Source File | 1986-06-04 | 9.9 KB | 325 lines

; SWEEP.ASM -- Runs program or command across subdirectories ; ========= ; ; (C) Copyright Charles Petzold, 1985 CSEG Segment Assume CS:CSEG, DS:CSEG, ES:CSEG, SS:CSEG Org 002Ch Environment Label Byte ; Segment of Environment is here Org 007Dh NewParam Label Byte ; Parameter to pass to COMMAND Org 0080h OldParam Label Byte ; Parameter passed to SWEEP Org 0100h Entry: Jmp Begin ; SWEEP.COM Entry Point ; Most Data (some more at end of program) ; --------- SweepMessage db 13,10,'>>> SWEEP >>> ' ; The SWEEP message CurrentDir db ?,':\' ; ? gets drive letter db '(C) Copyright Charles Petzold, 1985',1Ah DosVersMsg db 'Needs DOS 2.0 +$' ; Error Messages MemAllocMsg db 'Allocation Problem$' CommandMsg db 'SWEEP: COMMAND Problem$' AbnormalMsg db 'SWEEP: Abnormal Exit$' DosVersion dw ? ; Store DOS Version Number here BreakState db ? ; Store original break state here Comspec db 'COMSPEC=' ; String for Environment search CommandAsciiz dd ? ; Address of COMMAND.COM string ParamBlock dw ? ; Parameter block for EXEC call dw NewParam,? dw 5Ch,? dw 6Ch,? SearchAsciiZ db '*.*',0 ; Asciiz for Find call BackOneDir db '..',0 ; Asciiz for moving back one directory DtaPointer dw DtaAreaBegin ; For nested directory searches Direction db 0 ; Forward search initially ; Check DOS Version ; ----------------- Begin: Mov AH,30h ; Check for DOS Version Int 21h Cmp AL,2 ; See if it's 2.0 or above Jae DosVersOK ; If so, we can proceed Mov DX,Offset DosVersMsg ; Otherwise error message ErrorExit: Mov AH,9 ; Print String function call Int 21h ; Do it Int 20h ; And exit prematurely DosVersOK: Xchg AL,AH ; Get Major Version in AH Mov [DosVersion],AX ; And save whole thing ; Un-allocate rest of memory ; -------------------------- Mov SP,Offset StackTop ; Set new stack pointer Mov BX,Offset EndOfProgram ; This is beyond our needs Mov CL,4 ; Prepare for shift Shr BX,CL ; Convert to segment form Mov AH,4Ah ; Shrink allocated memory Int 21h ; By calling DOS Jnc MemAllocOK ; If no error, we can proceed Mov DX,Offset MemAllocMsg ; Otherwise set up for message Jmp ErrorExit ; Print it and terminate ; Search for Comspec in Environment ; --------------------------------- MemAllocOK: Push ES ; We'll be changing this Mov BX,Offset Environment ; Segment of Environment Mov ES,[BX] ; Set ES to it Assume ES:Nothing ; And tell the assembler Sub DI,DI ; Start at the beginning Mov SI,Offset ComSpec ; String to search for Cld ; Direction must be forward TryThis: Cmp Byte Ptr ES:[DI],0 ; See if points to zero Jz NoFindComSpec ; If so, we're dead in water Push SI ; Temporarily save these Push DI Mov CX,8 ; Search string has 8 chars Repz Cmpsb ; Do the string compare Pop DI ; Get back the registers Pop SI Jz FoundComspec ; If equals, we've found it Sub AL,AL ; Otherwise search for zero Mov CX,-1 ; For 'infinite' bytes Repnz Scasb ; Do the search Jmp TryThis ; And try the next string NoFindComSpec: Pop ES ; Get back ES on error Mov DX,Offset CommandMsg ; Set up error message Jmp ErrorExit ; And bow out gracefully FoundComspec: Add DI,8 ; so points after 'COMSPEC=' Mov Word Ptr [CommandASCIIZ],DI ; Save the address Mov Word Ptr [CommandASCIIZ + 2],ES ; including segment ; Set up parameter block for EXEC call ; ------------------------------------ Mov [ParamBlock],ES ; Segment of environment Mov [ParamBlock + 4],CS ; Segment of parameter Mov [ParamBlock + 8],CS ; Segment of 1st FCB Mov [ParamBlock + 12],CS ; Segment of 2nd FCB Pop ES ; Restores ES to this segment Assume ES:CSEG ; And make sure MASM knows ; Fix up new paramater for "/C" String ; ------------------------------------ Mov AL,[OldParam] ; Get old character count Add AL,3 ; Three more characters in paramater Mov [NewParam],AL ; New number of characters Mov [NewParam + 1],' ' ; Next is a blank Mov Word Ptr [NewParam + 2],'C/' ; Then a /C ; Get the current break state, drive, and subdirectory ; ---------------------------------------------------- Mov AX,3300h ; Get Break State Int 21h ; By calling DOS Mov [BreakState],DL ; Save it Sub DL,DL ; Set it to OFF Mov AX,3301h ; Set Break State Int 21h ; By calling DOS Mov DX,Offset Terminate ; For Ctrl-Break exits Mov AX,2523h ; Set Interrupt 23h vector Int 21h ; through DOS call Mov AH,19h ; Get current drive Int 21h ; By calling DOS Add AL,'A' ; Convert to letter Mov [CurrentDir],AL ; And save it Mov SI,Offset StartOffDir ; Repository of directory Sub DL,DL ; Indicate default drive Mov AH,47h ; Get current directory Int 21h ; By calling DOS ; Display SWEEP message with current drive and subdirectory ; --------------------------------------------------------- MainLoop: Mov SI,3 + Offset CurrentDir; Receives directory Sub DL,DL ; Indicate current drive Mov AH,47h ; Current directory call Int 21h ; Get it Mov SI,Offset SweepMessage ; String to display Cld ; Want direction forward DirPrintLoop: Lodsb ; Get the character Or AL,AL ; Check if it's zero Jz NoMoreDirPrint ; If so, branch out Mov DL,AL ; Otherwise set DL to it Mov AH,2 ; For Display Output Int 21h ; Display the character Jmp DirPrintLoop ; And loop around for the next NoMoreDirPrint: Mov CX,500 ; We'll hang out here awhile StatCheckLoop: Mov AH,0Bh ; Set up for keyboard status Int 21h ; Allow user to Break out Loop StatCheckLoop ; Do it a few more times Cmp [DosVersion],30Ah ; See if DOS is 3.1 or higher Jb LoadCommand ; If not, skip CR & LF Mov DL,13 ; Carriage Return Mov AH,2 ; Write to Display Int 21h ; by calling DOS Mov DL,10 ; Line Feed Mov AH,2 ; Write to Display Int 21h ; by calling DOS ; Load COMMAND.COM ; ----------------- LoadCommand: Mov BX,Offset ParamBlock ; ES:BX = parameter block Lds DX,[CommandAsciiz] ; DS:DX = Asciiz of COMMAND Sub AL,AL ; EXEC type zero Mov AH,4Bh ; EXEC function call Int 21h ; Load command processor ; Return from COMMAND.COM ; ----------------------- Mov AX,CS ; This is the current code segment Mov DS,AX ; Reset DS to this segment Mov ES,AX ; Reset ES to this segment Mov SS,AX ; Reset stack segment to it Mov SP,Offset StackTop ; And reset stack pointer also ; Avoid problems caused by commands that may change drive or directory ; -------------------------------------------------------------------- PushF ; Save EXEC Error Flag Sub DL,DL ; Set Break State to OFF Mov AX,3301h ; Set Break State Int 21h ; By calling DOS Mov DL,[CurrentDir] ; Get original drive letter Sub DL,'A' ; Convert to number Mov AH,0Eh ; Select disk Int 21h ; Through DOS call PopF ; Get back EXEC Error Flag Mov DX,Offset CommandMsg ; Set up possible error message Jc ErrorExit2 ; And print if EXEC error Mov DX,2 + Offset CurrentDir; The pre-COMMAND directory Mov AH,3Bh ; Call to change directory Int 21h ; Do it Jnc NextLevel ; Continue if no error Mov DX,Offset AbnormalMsg ; Otherwise set up message ErrorExit2: Mov AH,9 ; Will print the string Int 21h ; Print it Jmp Terminate ; And get out of here ; Find first or next subdirectory level ; ------------------------------------- NextLevel: Mov DX,[DTAPointer] ; Next nested DTA Mov AH,1Ah ; For DOS call to set DTA Int 21h ; Do it Cmp [Direction],0 ; Check if we're nesting Jnz FindNextFile ; If not, we're continuing Mov DX,Offset SearchAsciiZ ; We search for *.* Mov CX,10h ; Subdirectory attribute Mov AH,4Eh ; Find first file Int 21h ; by calling DOS Jmp Short TestMatch ; Hop around next section FindNextFile: Mov AH,4Fh ; Find next file Int 21h ; by calling DOS TestMatch: Jc NoMoreFiles ; If CY flag, at end of rope Mov BX,[DTAPointer] ; Our find stuff is here Test Byte Ptr [BX + 21],10h ; Test if directory attribute Jz FindNextFile ; If not, continue search Add BX,30 ; Now points to directory name Cmp Byte Ptr [BX],'.' ; Ignore "." and ".." entries Jz FindNextFile ; by continuing the search Mov DX,BX ; Now DX points to found dir Mov AH,3Bh ; Set up DOS function call Int 21h ; And change directory Add [DtaPointer],43 ; New DTA for new level Mov [Direction],0 ; I.E., Find first file Jmp MainLoop ; All ready to cycle through ; No More Files Found -- go back to previous level ; ------------------------------------------------ NoMoreFiles: Cmp [DTAPointer],Offset DtaAreaBegin ; See if back at start Jz Terminate ; If so, that's all, folks Sub [DTAPointer],43 ; Back one for previous Mov [Direction],-1 ; I.E., will find next file Mov DX,Offset BackOneDir ; The string ".." Mov AH,3Bh ; Call to change directory Int 21h ; Change directory to father Jmp NextLevel ; And continue the search Terminate: Mov DX,Offset RestoreDir ; Original subdirectory Mov AH,3Bh ; Call to change directory Int 21h ; Do it Mov DL,[BreakState] ; Original break-state Mov AX,3301h ; Change the break-state Int 21h ; by calling DOS Int 20h ; Terminate program RestoreDir db '\' ; For eventual restore StartOffDir Label Byte ; Place for original directory StackBottom equ StartOffDir + 64 ; Stack area beyond that StackTop equ StackBottom + 100h ; The top of the stack DtaAreaBegin equ StackTop ; is also the DTA area DtaAreaEnd equ DtaAreaBegin + 32 * 43 ; Can have 32 DTAs of 43 bytes EndOfProgram equ DtaAreaEnd + 15 ; This is beyond our needs CSEG EndS ; End of the segment End Entry ; Denotes entry point