Night Owl 6

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/ Night Owl 6 / Night Owl's Shareware - PDSI-006 - Night Owl Corp (1990).iso / 010a / dietdisc.zip / DIETDISK.ASM < prev next >

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Assembly Source File | 1991-02-10 | 176KB | 5,992 lines

;-----------------------------------------------------------------; ; ; ; DietDisk Version 1.0 ; ; ; ; Copyright (c) 1990 Barry Nance ; ; Released to the Public Domain ; ; ; ; Distributed from BIX, the BYTE Magazine Information ; ; Exchange ; ; ; ;-----------------------------------------------------------------; CallDOS Macro _func Mov AH, _func PushF CLI Call CS:OldInt21 EndM ;-----------------------------------------------------------------; ; Equates ; ;-----------------------------------------------------------------; StdOut = 0001 ;file handle for StdOut MaxName = 80 ;max size of a filename MaxHandles = 10 ;max number of file handles we do MaxBuf = 2048 ;buffer size NumPtrs = 250 ;number of ptrs on a ptr rec MaxTextBuf = 1024 ;text buffer size ; equates for DOS operations DiskReset = 0Dh FCBOpenOp = 0Fh FCBCloseOp = 10h FCBSeqReadOp = 14h FCBSeqWriteOp = 15h FCBCreateOp = 16h FCBRandReadOp = 21h FCBRandWriteOp = 22h FCBFileSizeOp = 23h FCBRelRecOp = 24h FCBBlockReadOp = 27h FCBBlockWriteOp = 28h CurrentDiskOp = 19h SetDTAOp = 1Ah GetDTAOp = 2Fh GetVerOp = 30h SetVectorOp = 25h GetVectorOp = 35h CreateOp = 3Ch OpenOp = 3Dh CloseOp = 3Eh ReadOp = 3Fh WriteOp = 40h DeleteOp = 41h SeekOp = 42h IOCTL = 44h DupeHandOp = 45h ForceDupeOp = 46h GetCurrDir = 47h ExecPgmOp = 4Bh CreateNewOp = 5Bh LockOp = 5Ch CommitOp = 68h Term00Op = 00h Term31Op = 31h Term4COp = 4Ch FDateTimeOp = 57h ; equates for Lempel/Ziv/Welch compression/decompression clear = 256 ;Clear code eof = 257 ;End of file marker first_free = 258 ;First free code maxmax = 1024 ;Max code + 1 K512 = 512 K256 = 256 K10 = 10 K9 = 9 ;-----------------------------------------------------------------; ; Physical beginning of program ; ;-----------------------------------------------------------------; PSP Segment Assume CS:PSP, DS:PSP, ES:PSP Org 100h Program: Jmp Start ;-----------------------------------------------------------------; ; Data area ; ;-----------------------------------------------------------------; AskFlag DW 0 Banner DB "Diet Disk V1.0" DietDir DB "Diet.Dir" DB 0 LDietDir = $ - DietDir DietPath DB MaxName dup(0) DietDirHandle DW ? DeCompPID DW 0 DeCompHandle DW 0 DeCompFilePos DD 0 DeCompBlock DW 0FFFFh ; force it to be read 1st time DeCompDirty DW 0 OldPID DW ? CurrHandle DW ? CurrFilePos DD ? CurrBlock DW ? BlockPos DW ? OldInt21 Label DWord OldInt21Ofs DW ? OldInt21Seg DW ? OldInt20 Label DWord OldInt20Ofs DW ? OldInt20Seg DW ? OldSP DW ? OldSS DW ? OurSP DW ? OurSS DW ? Junk DW ? OurPID DW ? CtrlHandle DW ? CtrlPID DW ? CtrlDirty DW 0 PtrsHandle DW ? PtrsPID DW ? PtrsFilePos DD 0016 PtrsDirty DW 0 PointersStart DW 0 PointersEnd DW NumPtrs-1 CharPos DW ? TablePtr DW 0 FCBTablePtr DW 0 ; ; table of file handles for skinny files ; FileHandleTbl Label Word DW MaxHandles dup(0FFFFh) ; ; table of Process ID's for the processes that have skinny files ; PIDTbl Label Word DW MaxHandles dup(0FFFFh) ; ; table of current file positions (virtual, not actual) for our files ; FilePosTbl Label DWord DD MaxHandles dup(0) DupeTable Label Word DW MaxHandles*2 dup(0FFFFh) ; ; a table of remembered file names from FCB's created/opened ; FCBTable Label Byte DB MaxHandles * 12 dup(" ") DB 0, 0 ; ; some buffers (filenames, etc.) ; NameBuffer DB MaxName+2 Dup(0) CreateName DB MaxName+2 Dup(0) ScreenSave DB 160 Dup(0) fbufbytes DW 0 fbufndx DW MaxTextBuf ; ; some other data ; AskMessage1 Label Byte DB "Should " AMLen1 = $-AskMessage1 AskMessage2 Label Byte DB " be decompressed? (Y/N) " AMLen2 = $-AskMessage2 ReadErrorMessage Label Byte DB " Damaged file (disk data may be lost). Press ─┘ to continue. " LReadError = $-ReadErrorMessage WriteErrorMessage Label Byte DB " Disk full, or damaged file (disk data may be lost). Press ─┘ to continue. " LWriteError = $-WriteErrorMessage TooManyError Label Byte DB " Too many compressed files open at once (limit 10). Press ─┘ to continue. " LTooManyError = $-TooManyError FileCount DW 0 AnswerPos DW 0 CPosSave DW 0 CTypSave DW 0 FCBPtr Label DWord FCBOfs DW ? FCBSeg DW ? ; ; ApplBufferPtr stores the DX:DS buffer pointer for certain DOS operations ; ApplBufferPtr Label DWord CreatePtr Label DWord R_DX DW ? ; register contents at entry to DOS R_DS DW ? R_CX DW ? R_AL DB ? R_AX DW ? R_SI DW ? R_DI DW ? ; ; some more data ; DietEOF DW ? CreateLength DW ? DirLength DW ? OurDTA Label DWord OurDTAOfs DW ? OurDTASeg DW ? OldDTA Label DWord OldDTAOfs DW ? OldDTASeg DW ? EndOfBlock DW ? BytesMoved DW ? RD_ONLY DB ? RD_WR DB ? CompressLength DW ? FirstEmpty DB ? NumBlocks DW ? AdvancePtr DW ? TotalLength DD ? PointerBlock DW 0 LinkLength DW ? LinkLocation DD ? CurrLen DW ? CurrPtr DD ? LenToWrite DW ? NextPtr DD ? PrevPtr DD ? NextLen DW ? PtrRecSegment DW ? WritePtr DW ? GetCtrlHandle DW ? GetCtrlPID DW ? GetPtrsHandle DW ? GetPtrsPID DW ? PutCtrlHandle DW ? PutCtrlPID DW ? PutPtrsHandle DW ? PutPtrsPID DW ? CritFlag DW 0 DOSVersion DB ? DOSVersMin DB ? IOFlag DW 0 Int24Ptr Label DWord Int24Ofs DW ? Int24Seg DW ? ; ; a buffer for reading files to see if they have a footprint ; FootBuffer DB 16 dup(?) ; ; a "zero-mask" for the control record ; Control_ZM Label Byte DB "lZdIeT" ; footprint (6 bytes) DD 0 ; current file length (virtual) DB 6 dup(0) ; filler Ctrl_ZM_Size = $-Control_ZM ; ; I/O and de-compression buffers ; Even CtrlBuffer Label Byte CtrlFootPrint DB 6 dup(?) Ctrl_FileLen DD ? DB 6 dup(?) CtrlSize = $-CtrlBuffer Even Ctrl_Pointers Label Byte Ctrl_Next DD ? Ctrl_Prev DD ? DB 8 dup(?) Loc_Len_Info DB NumPtrs*6 dup(?) PtrsSize = $-Ctrl_Pointers EndOfCtrlRec Label Byte Even DeCompBuffer Label Byte ILinkPtr DD ? ILinkLen DW ? DB MaxBuf+512 dup(?) Even IOBuffer Label Byte OLinkPtr DD ? OLinkLen DW ? DB MaxBuf+512 dup(?) ; ;Hash table ; Even Hash Label Byte Next DW ? ; Next entry along chain DW maxmax dup(?) Char DB ? ; Suffix char DB maxmax dup(?) First DW ? ; First entry with this value DW maxmax dup(?) ; ; other compression-related items ; Prefix_Code DW ? Free_Code DW ? Max_Code DW ? NBits DW ? K DB ? Bit_Offset DW ? Input_Offset DW 0 Input_Size DW 0 Cur_Code DW ? Old_Code DW ? In_Code DW ? Stack_Count DW 0 Fin_Char DB ? Masks DW 1ffh, 3ffh, 7ffh, 0fffh Output_Offset DW 0 ;-----------------------------------------------------------------; ; INT 21 interception ; ;-----------------------------------------------------------------; DOS_Handler Proc Far ISR_21: PushF STI Mov CS:IOFlag, 0 CaseFunc00: Cmp AH, Term00Op JNE CaseFunc31 Jmp DoTerm CaseFunc31: Cmp AH, Term31Op JNE CaseFunc4C Jmp DoTerm CaseFunc4C: Cmp AH, Term4COp JNE CaseCreate Jmp DoTerm CaseCreate: Cmp AH, CreateOp JNE CaseOpen Jmp DoCreate CaseOpen: Cmp AH, OpenOp JNE CaseClose Jmp DoOpen CaseClose: Cmp AH, CloseOp JNE CaseRead Jmp DoClose CaseRead: Cmp AH, ReadOp JNE CaseWrite Jmp DoRead CaseWrite: Cmp AH, WriteOp JNE CaseSeek Jmp DoWrite CaseSeek: Cmp AH, SeekOp JNE CaseDupe Jmp DoSeek CaseDupe: Cmp AH, DupeHandOp JNE CaseForceDupe Jmp DoDupe CaseForceDupe: Cmp AH, ForceDupeOp JNE CaseLock Jmp DoForceDupe CaseLock: Cmp AH, LockOp JNE CaseCreateNew Jmp DoLockUnlock CaseCreateNew: Cmp AH, CreateNewOp JNE CaseFCBOpen Jmp DoCreateNew CaseFCBOpen: Cmp AH, FCBOpenOp JNE CaseFCBClose Jmp DoFCBOpen CaseFCBClose: Cmp AH, FCBCloseOp JNE CaseFCBSeqRead Jmp DoFCBClose CaseFCBSeqRead: Cmp AH, FCBSeqReadOp JNE CaseFCBSeqWrite Jmp DoFCBSeqRead CaseFCBSeqWrite: Cmp AH, FCBSeqWriteOp JNE CaseFCBCreate Jmp DoFCBSeqWrite CaseFCBCreate: Cmp AH, FCBCreateOp JNE CaseFCBRandRead Jmp DoFCBCreate CaseFCBRandRead: Cmp AH, FCBRandReadOp JNE CaseFCBRandWrite Jmp DoFCBRandRead CaseFCBRandWrite: Cmp AH, FCBRandWriteOp JNE CaseFCBFileSize Jmp DoFCBRandWrite CaseFCBFileSize: Cmp AH, FCBFileSizeOp JNE CaseFCBBlockRead Jmp DoFCBFileSize CaseFCBBlockRead: Cmp AH, FCBBlockReadOp JNE CaseFCBBlockWrite Jmp DoFCBBlockRead CaseFCBBlockWrite: Cmp AH, FCBBlockWriteOp JNE CaseCtlBrkCheck Jmp DoFCBBlockWrite CaseCtlBrkCheck: Cmp AX, 3341h JNE DefaultDOS Jmp DoInstalledResponse DefaultDOS: PopF Jmp CS:OldInt21 ; let DOS handle it normally ;-----------------------------------------------------------------; ; AX=3341h, Int 21h asks if we are loaded. Answer yes. ; ;-----------------------------------------------------------------; DoInstalledResponse: Mov DX, 1234h Mov CX, CS Mov CS:IOFlag, 0 Jmp ExitDOS ;-----------------------------------------------------------------; ; Handle Program Terminate Functions ; ;-----------------------------------------------------------------; DoTerm: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD Call CloseRemaining CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle Create-File Function Call ; ;-----------------------------------------------------------------; DoCreate: CallDOS CreateOp JNC DoCreate_1 Jmp BadDOS ; if not created, don't process DoCreate_1: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_DS, DS ; save ptr to AsciiZ name Mov CS:R_DX, DX Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD Mov CurrHandle, AX Call GetOldPID Call SearchTable JC DoCreate_5 Call ForgetThisFile DoCreate_5: Call SearchDietDir ; look in the Diet.Dir file JC DoCreate_9 ; if not in Diet.Dir Call WriteInitControl ; initialize skinny file Call RememberThisFile DoCreate_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp ExitDOS ;-----------------------------------------------------------------; ; Handle Open-File Function Call ; ;-----------------------------------------------------------------; DoOpen: CallDOS OpenOp JNC DoOpen_1 Jmp BadDOS ; if bad open, we can't do anything DoOpen_1: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_DS, DS ; save ptr to AsciiZ name Mov CS:R_DX, DX Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD Mov CurrHandle, AX Call GetOldPID ; which process is opening a file? Call SearchTable JC DoOpen_5 Call ForgetThisFile DoOpen_5: Cmp AskFlag, 2 JNE DoOpen_5A Jmp DoOpen_9 DoOpen_5A: Call ReadFootPrint JNC DoOpen_5B Jmp DoOpen_9 DoOpen_5B: Cmp AskFlag, 1 JNE DoOpen_7 Call SaveLine25 JC DoOpen_7 Mov DX, 1800h Mov AnswerPos, 0 Mov DI, Offset AskMessage1 Mov CX, AMLen1 Add AnswerPos, CX Call AttrCharOut Push DX Call Parse_DS_DX_Name Pop DX Mov DI, Offset CreateName Mov CX, CreateLength Add AnswerPos, CX Call AttrCharOut Mov DI, Offset AskMessage2 Mov CX, AMLen2 Add AnswerPos, CX Call AttrCharOut GetAnswer: Mov AH, 2 Mov BH, 0 Mov DX, 1800h Add DX, AnswerPos Dec DX Dec DX Int 10h Mov AH, 0 Int 16h Cmp AL, 'Y' JE AnswerIsYes Cmp AL, 'y' JE AnswerIsYes Cmp AL, 'N' JE AnswerIsNo Cmp AL, 'n' JE AnswerIsNo Jmp GetAnswer AnswerIsNo: Call RestLine25 Jmp DoOpen_9 AnswerIsYes: Call RestLine25 DoOpen_7: Call RememberThisFile ; save file handle, etc. in table Mov AX, CurrHandle Mov GetCtrlHandle, AX Mov GetPtrsHandle, AX Mov AX, OldPID Mov GetCtrlPID, AX Mov GetPtrsPID, AX Call GetControlRec Mov PointerBlock, 0 Call GetPointerRec DoOpen_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; back to the application Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp ExitDOS ;-----------------------------------------------------------------; ; Handle Close-File Function Call ; ;-----------------------------------------------------------------; DoClose: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD Mov CurrHandle, BX Call GetOldPID ; process that's closing a file Call SearchTable ; is it one of ours? JC DoClose_9 ; no Mov BX, CurrHandle Cmp BX, DeCompHandle JNE DoClose_8 Mov AL, 0 CallDOS FDateTimeOp Push CX Push DX Call PutBlock Call WritePointerRec Call WriteTheCtrlRec Pop DX Pop CX Mov BX, CurrHandle Mov AL, 1 CallDOS FDateTimeOp DoClose_8: Call ForgetThisFile DoClose_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; back to the application Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle Read-File Function Call ; ;-----------------------------------------------------------------; DoRead: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:R_DS, DS Mov CS:R_DX, DX Mov CS:R_CX, CX Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? ; Mov CurrHandle, BX Call GetOldPID Call SearchTable JNC DoRead_1 ; it's a skinny file Jmp DoRead_9 ; not one of ours (let DOS do it) DoRead_1: Call Get_CX_Bytes_To_DSDX Call AlignDupedFiles DoRead_8: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; read request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:BytesMoved Jmp ExitDOS ; ; file is not skinny....let DOS handle it. ; DoRead_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle Write-File Function Call ; ;-----------------------------------------------------------------; DoWrite: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:R_DS, DS Mov CS:R_DX, DX Mov CS:R_CX, CX Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? ; Mov CurrHandle, BX Call GetOldPID Call SearchTable JNC DoWrite_1 ; it's a skinny file Jmp DoWrite_9 ; not one of ours (let DOS do it) DoWrite_1: Call Put_CX_Bytes_From_DSDX CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; write request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:BytesMoved Jmp ExitDOS ; ; file is not skinny....let DOS handle it. ; DoWrite_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle Seek-File Function Call ; ;-----------------------------------------------------------------; DoSeek: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:R_DX, DX Mov CS:R_CX, CX Mov CS:R_AL, AL Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? ; Mov CurrHandle, BX Call GetOldPID Call SearchTable JNC DoSeek_0 ; it's a skinny file Jmp DoSeek_9 ; not one of ours (let DOS do it) DoSeek_0: Mov BX, TablePtr Shl BX, 1 Mov CX, R_CX Mov DX, R_DX Cmp R_AL, 0 JNE DoSeek_1 ; ; seek from *beginning* of file ; Mov Word Ptr FilePosTbl [BX], DX Mov Word Ptr FilePosTbl [BX+2], CX Jmp DoSeek_8 DoSeek_1: Cmp R_AL, 1 JNE DoSeek_2 ; ; seek from *current* position ; Add DX, Word Ptr FilePosTbl [BX] Adc CX, Word Ptr FilePosTbl [BX+2] Mov Word Ptr FilePosTbl [BX], DX Mov Word Ptr FilePosTbl [BX+2], CX Jmp DoSeek_8 DoSeek_2: ; ; seek from *end* of file ; Mov AX, CurrHandle Mov GetCtrlHandle, AX Mov AX, OldPID Mov GetCtrlPID, AX Call GetControlRec Add DX, Word Ptr Ctrl_FileLen Adc CX, Word Ptr Ctrl_FileLen+2 Mov Word Ptr FilePosTbl [BX], DX Mov Word Ptr FilePosTbl [BX+2], CX DoSeek_8: Mov R_CX, CX Mov R_DX, DX Call AlignDupedFiles CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; seek request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov DX, Word Ptr CS:R_CX Mov AX, Word Ptr CS:R_DX Jmp ExitDOS ; ; file is not skinny....let DOS handle it. ; DoSeek_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle Dupe-Handle Function Call ; ;-----------------------------------------------------------------; DoDupe: CallDOS DupeHandOp JNC DoDupe_0 Jmp BadDOS DoDupe_0: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_AX, AX Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? Mov CurrHandle, BX Call GetOldPID Call SearchTable JNC DoDupe_1 ; it's a skinny file Jmp DoDupe_8 ; not one of ours (let DOS do it) DoDupe_1: Push TablePtr Mov AX, R_AX Mov CurrHandle, AX Call RememberThisFile Call SearchTable Mov DI, TablePtr Pop TablePtr Mov SI, TablePtr Mov DupeTable [DI], SI Mov DupeTable [SI], DI Call AlignDupedFiles DoDupe_8: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp ExitDOS ;-----------------------------------------------------------------; ; Handle Force-Dupe-Handle Function Call ; ;-----------------------------------------------------------------; DoForceDupe: CallDOS ForceDupeOp JNC DoForce_0 Jmp BadDOS DoForce_0: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_CX, CX Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? Mov CurrHandle, BX Call GetOldPID Call SearchTable JNC DoForce_1 ; it's a skinny file Jmp DoForce_8 ; not one of ours (let DOS do it) DoForce_1: Push TablePtr Mov CX, R_CX Mov CurrHandle, CX Call RememberThisFile Mov DI, TablePtr Pop TablePtr Mov SI, TablePtr Mov DupeTable [DI], SI Mov DupeTable [SI], DI Call AlignDupedFiles DoForce_8: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp ExitDOS ;-----------------------------------------------------------------; ; Handle Lock/Unlock Function Call ; ;-----------------------------------------------------------------; DoLockUnlock: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_AL, AL Mov CS:R_CX, CX Mov CS:R_DX, DX Mov CS:R_SI, SI Mov CS:R_DI, DI Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? Mov CurrHandle, BX Call GetOldPID Call SearchTable JNC DoLock_0 ; it's a skinny file Jmp DoLock_9 ; not one of ours (let DOS do it) DoLock_0: Mov BX, CurrHandle Mov CX, 0 Mov DX, CX Mov SI, 0FFFFh Mov DI, SI Mov AL, R_AL CallDOS LockOp JNC LockOk Mov R_AX, AX CLI Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Jmp BadDOS LockOk: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp ExitDOS DoLock_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle Create-New Function Call ; ;-----------------------------------------------------------------; DoCreateNew: CallDOS CreateNewOp JNC DoCreateNew_0 Jmp BadDOS DoCreateNew_0: Jmp DoCreate_1 ;-----------------------------------------------------------------; ; Handle FCB Open Function Call ; ;-----------------------------------------------------------------; DoFCBOpen: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_DX, DX Mov CS:R_DS, DS Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD Call GetOldPID Call SearchFCBTable JC FCBOpen_0 Mov SI, TablePtr Mov BX, FileHandleTbl [SI] Mov CurrHandle, BX Jmp FCBOpen_7 ; Parse FCB name into NameBuffer and then do a regular handle-open. FCBOpen_0: Call ParseFCBName Mov DX, Offset NameBuffer Mov AL, 02 CallDOS OpenOp JNC FCBOpenOk Mov DX, Offset NameBuffer Mov AL, 00 CallDOS OpenOp JNC FCBOpenOk Jmp FCBOpen_9 FCBOpenOk: Mov CurrHandle, AX Call GetOldPID ; which process is opening a file? Call SearchTable ; get a TablePtr value FCBOpen_5: Cmp AskFlag, 2 JNE FCBOpen_5A Mov BX, CurrHandle CallDOS CloseOp Jmp FCBOpen_9 FCBOpen_5A: Call ReadFootPrint ; look for our footprint JNC FCBOpen_5B Mov BX, CurrHandle CallDOS CloseOp Jmp FCBOpen_9 ; not there...it's not skinny FCBOpen_5B: Cmp AskFlag, 1 JNE FCBOpen_7 Call SaveLine25 JC FCBOpen_7 Mov DX, 1800h Mov AnswerPos, 0 Mov DI, Offset AskMessage1 Mov CX, AMLen1 Add AnswerPos, CX Call AttrCharOut Mov DI, Offset NameBuffer Mov CX, CreateLength Add AnswerPos, CX Call AttrCharOut Mov DI, Offset AskMessage2 Mov CX, AMLen2 Add AnswerPos, CX Call AttrCharOut FCBGetAnswer: Mov AH, 2 Mov BH, 0 Mov DX, 1800h Add DX, AnswerPos Dec DX Dec DX Int 10h Mov AH, 0 Int 16h Cmp AL, 'Y' JE FCBAnswerIsYes Cmp AL, 'y' JE FCBAnswerIsYes Cmp AL, 'N' JE FCBAnswerIsNo Cmp AL, 'n' JE FCBAnswerIsNo Jmp FCBGetAnswer FCBAnswerIsNo: Call RestLine25 Mov BX, CurrHandle CallDOS CloseOp Jmp FCBOpen_9 FCBAnswerIsYes: Call RestLine25 FCBOpen_7: Call RememberThisFile ; save file handle, etc. in table Mov AX, CurrHandle Mov GetCtrlHandle, AX Mov GetPtrsHandle, AX Mov AX, OldPID Mov GetCtrlPID, AX Mov GetPtrsPID, AX Call GetControlRec Mov PointerBlock, 0 Call GetPointerRec LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBOpen_7A Add DI, 7 FCBOpen_7A: Mov BP, DI Cmp Byte Ptr ES:[DI], 0 JNE FCBOpen_7B CallDOS CurrentDiskOp Inc AL Mov Byte Ptr ES:[DI], AL FCBOpen_7B: Mov Word Ptr ES:[DI+12], 0 Mov Word Ptr ES:[DI+14], 80h Mov BX, CurrHandle Mov AL, 0 CallDOS FDateTimeOp Mov Word Ptr ES:[DI+20], DX Mov AX, Word Ptr Ctrl_FileLen Mov Word Ptr ES:[DI+16], AX Mov AX, Word Ptr Ctrl_FileLen+2 Mov Word Ptr ES:[DI+18], AX Push DS Pop ES Mov AX, 12 Mul TablePtr Mov DI, Offset FCBTable Add DI, AX Mov CX, 6 Push DS Mov DS, FCBSeg Mov SI, BP Rep MovSW Pop DS FCBOpen_8: Mov R_AX, 0F00h CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Jmp ExitDOS FCBOpen_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle FCB Close Function Call ; ;-----------------------------------------------------------------; DoFCBClose: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_DX, DX Mov CS:R_DS, DS Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? Call SearchFCBTable JNC FCBClose_ThisOne Jmp DoFCBClose_9 ; not one of ours (let DOS do it) FCBClose_ThisOne: Mov SI, TablePtr Mov BX, FileHandleTbl [SI] Mov CurrHandle, BX Call GetOldPID ; process that's closing a file Mov BX, CurrHandle Cmp BX, DeCompHandle JNE FCBClose_7 Mov AL, 0 CallDOS FDateTimeOp Push CX Push DX Call PutBlock Call WritePointerRec Call WriteTheCtrlRec Pop DX Pop CX Mov BX, CurrHandle Mov AL, 1 CallDOS FDateTimeOp FCBClose_7: Call ForgetThisFile Mov BX, CurrHandle CallDOS CloseOp Push DS Pop ES Mov DI, FCBTablePtr Mov CX, 6 Mov AX, 2020h Rep StoSW DoFCBClose_8: Mov R_AX, 1000h CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Jmp ExitDOS DoFCBClose_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle FCB Seq Read Function Call ; ;-----------------------------------------------------------------; DoFCBSeqRead: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_DX, DX Mov CS:R_DS, DS Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? Call SearchFCBTable JNC DoFCBSeqRead_0 ; it's a skinny file Jmp DoFCBSeqRead_9 ; not one of ours (let DOS do it) DoFCBSeqRead_0: Mov SI, TablePtr Mov AX, FileHandleTbl [SI] Mov CurrHandle, AX Call GetOldPID CallDOS GetDTAOp Mov R_DX, BX Mov R_DS, ES LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBSeqReadNotExt Add DI, 7 FCBSeqReadNotExt: Mov CX, Word Ptr ES:[DI+14] Mov R_CX, CX Xor AX, AX Mov AL, Byte Ptr ES:[DI+32] Mov BP, AX Mov AX, 128 Mul Word Ptr ES:[DI+12] Add AX, BP Adc DX, 0 Mov BX, Word Ptr ES:[DI+14] XOR CX, CX XCHG AX,SI XCHG AX,DX TEST AX,AX JZ LMul2A MUL BX LMul2A: XCHG AX,CX TEST AX,AX JZ LMul3A MUL SI ADD CX,AX LMul3A: XCHG AX,SI MUL BX ADD DX,CX Mov SI, TablePtr Shl SI, 1 Mov Word Ptr FilePosTbl [SI], AX Mov Word Ptr FilePosTbl [SI+2], DX Call Get_CX_Bytes_To_DSDX Mov R_AX, 1400h Cmp R_CX, 0 JE FCBSeqRead_5 Cmp BytesMoved, 0 JA FCBSeqReadSomeBytes Mov R_AX, 1401h Jmp FCBSeqRead_5 FCBSeqReadSomeBytes: Mov AX, BytesMoved Cmp AX, R_CX JE FCBSeqRead_5 Mov R_AX, 1403h FCBSeqRead_5: LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBSeqReadNotExt2 Add DI, 7 FCBSeqReadNotExt2: Inc Byte Ptr ES:[DI+32] Cmp Byte Ptr ES:[DI+32], 80h JB DoFCBSeqRead_8 Mov Byte Ptr ES:[DI+32], 0 Inc Word Ptr ES:[DI+12] DoFCBSeqRead_8: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Jmp ExitDOS DoFCBSeqRead_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle FCB Seq Write Function Call ; ;-----------------------------------------------------------------; DoFCBSeqWrite: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_DX, DX Mov CS:R_DS, DS Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? Call SearchFCBTable JNC DoFCBSeqWrite_0 ; it's a skinny file Jmp DoFCBSeqWrite_9 ; not one of ours (let DOS do it) DoFCBSeqWrite_0: Mov SI, TablePtr Mov AX, FileHandleTbl [SI] Mov CurrHandle, AX Call GetOldPID CallDOS GetDTAOp Mov R_DX, BX Mov R_DS, ES LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBSeqWriteNotExt Add DI, 7 FCBSeqWriteNotExt: Mov CX, Word Ptr ES:[DI+14] Mov R_CX, CX Xor AX, AX Mov AL, Byte Ptr ES:[DI+32] Mov BP, AX Mov AX, 128 Mul Word Ptr ES:[DI+12] Add AX, BP Adc DX, 0 Mov BX, Word Ptr ES:[DI+14] XOR CX, CX XCHG AX,SI XCHG AX,DX TEST AX,AX JZ LMul2B MUL BX LMul2B: XCHG AX,CX TEST AX,AX JZ LMul3B MUL SI ADD CX,AX LMul3B: XCHG AX,SI MUL BX ADD DX,CX Mov SI, TablePtr Shl SI, 1 Mov Word Ptr FilePosTbl [SI], AX Mov Word Ptr FilePosTbl [SI+2], DX Call Put_CX_Bytes_From_DSDX Mov R_AX, 1500h Mov AX, BytesMoved Cmp AX, R_CX JE FCBSeqWrite_5 Mov R_AX, 1501h FCBSeqWrite_5: LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBSeqWriteNotExt2 Add DI, 7 FCBSeqWriteNotExt2: Inc Byte Ptr ES:[DI+32] Cmp Byte Ptr ES:[DI+32], 80h JB FCBSeqWriteSameBlock Mov Byte Ptr ES:[DI+32], 0 Inc Word Ptr ES:[DI+12] FCBSeqWriteSameBlock: Mov AX, Word Ptr Ctrl_FileLen Mov Word Ptr ES:[DI+16], AX Mov AX, Word Ptr Ctrl_FileLen+2 Mov Word Ptr ES:[DI+18], AX DoFCBSeqWrite_8: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Jmp ExitDOS DoFCBSeqWrite_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle FCB Create Function Call ; ;-----------------------------------------------------------------; DoFCBCreate: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD Call GetOldPID Call SearchFCBTable JC FCBCreate_0 Mov SI, TablePtr Mov BX, FileHandleTbl [SI] Mov CurrHandle, BX CallDOS CloseOp Call ParseFCBName Mov DX, Offset NameBuffer CallDOS DeleteOp Call ForgetThisFile Push DS Pop ES Mov DI, FCBTablePtr Mov CX, 6 Mov AX, 2020h Rep StoSW ; Parse FCB name into FootBuffer and then do a regular handle-create. FCBCreate_0: Call ParseFCBName Mov CX, CreateLength Inc CX Mov DI, Offset FootBuffer Mov SI, Offset NameBuffer Rep MovSB Mov R_DX, Offset FootBuffer Mov R_DS, DS Call SearchDietDir JNC FCBCreate_1 Jmp FCBCreate_9 FCBCreate_1: Mov DX, Offset FootBuffer Mov CX, 0 CallDOS CreateOp JNC FCBCreateOk Jmp FCBCreate_9 FCBCreateOk: Mov CurrHandle, AX Call SearchTable ; get a TablePtr value Call WriteInitControl ; initialize skinny file Call RememberThisFile FCBCreatedAlready: LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBCreate_7A Add DI, 7 FCBCreate_7A: Mov BP, DI Cmp Byte Ptr ES:[DI], 0 JNE FCBCreate_7B CallDOS CurrentDiskOp Inc AL Mov Byte Ptr ES:[DI], AL FCBCreate_7B: Mov Word Ptr ES:[DI+12], 0 Mov Word Ptr ES:[DI+14], 80h Mov BX, CurrHandle Mov AL, 0 CallDOS FDateTimeOp Mov Word Ptr ES:[DI+20], DX Mov Word Ptr ES:[DI+16], 0 Mov Word Ptr ES:[DI+18], 0 Push DS Pop ES Mov AX, 12 Mul TablePtr Mov DI, Offset FCBTable Add DI, AX Mov CX, 6 Push DS Mov DS, FCBSeg Mov SI, BP Rep MovSW Pop DS FCBCreate_8: Mov R_AX, 1600h CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Jmp ExitDOS FCBCreate_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle FCB Rand Read Function Call ; ;-----------------------------------------------------------------; DoFCBRandRead: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_DX, DX Mov CS:R_DS, DS Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? ; Call SearchFCBTable JNC DoFCBRndRead_0 ; it's a skinny file Jmp DoFCBRndRead_9 ; not one of ours (let DOS do it) DoFCBRndRead_0: Mov SI, TablePtr Mov AX, FileHandleTbl [SI] Mov CurrHandle, AX Call GetOldPID CallDOS GetDTAOp Mov R_DX, BX Mov R_DS, ES LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBRndReadNotExt Add DI, 7 FCBRndReadNotExt: Mov CX, Word Ptr ES:[DI+14] Mov R_CX, CX Mov AX, Word Ptr ES:[DI+33] Cmp CX, 64 JB FCBRndReadRecNLT64 Xor DX, DX Mov DL, Byte Ptr ES:[DI+35] Jmp FCBRndReadGotRecN FCBRndReadRecNLT64: Mov DX, Word Ptr ES:[DI+35] FCBRndReadGotRecN: Push AX Push DX Mov CX, 128 DIV CX Mov Word Ptr ES:[DI+12], AX Mov Byte Ptr ES:[DI+32], DL Pop DX Pop AX Mov BX, Word Ptr ES:[DI+14] XOR CX, CX XCHG AX,SI XCHG AX,DX TEST AX,AX JZ LMul2C MUL BX LMul2C: XCHG AX,CX TEST AX,AX JZ LMul3C MUL SI ADD CX,AX LMul3C: XCHG AX,SI MUL BX ADD DX,CX Mov SI, TablePtr Shl SI, 1 Mov Word Ptr FilePosTbl [SI], AX Mov Word Ptr FilePosTbl [SI+2], DX Call Get_CX_Bytes_To_DSDX Mov R_AX, 2100h Cmp R_CX, 0 JE FCBRndRead_5 Cmp BytesMoved, 0 JA FCBRndReadSomeBytes Mov R_AX, 2101h Jmp FCBRndRead_5 FCBRndReadSomeBytes: Mov AX, BytesMoved Cmp AX, R_CX JE FCBRndRead_5 Mov R_AX, 2103h FCBRndRead_5: DoFCBRandRead_8: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Jmp ExitDOS DoFCBRndRead_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle FCB Rand Write Function Call ; ;-----------------------------------------------------------------; DoFCBRandWrite: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_DX, DX Mov CS:R_DS, DS Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? ; Call SearchFCBTable JNC DoFCBRndWrite_0 ; it's a skinny file Jmp DoFCBRndWrite_9 ; not one of ours (let DOS do it) DoFCBRndWrite_0: Mov SI, TablePtr Mov AX, FileHandleTbl [SI] Mov CurrHandle, AX Call GetOldPID CallDOS GetDTAOp Mov R_DX, BX Mov R_DS, ES LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBRndWriteNotExt Add DI, 7 FCBRndWriteNotExt: Mov CX, Word Ptr ES:[DI+14] Mov R_CX, CX Mov AX, Word Ptr ES:[DI+33] Cmp Word Ptr ES:[DI+14], 64 JB FCBRndWriteRecNLT64 Xor DX, DX Mov DL, Byte Ptr ES:[DI+35] Jmp FCBRndWriteGotRecN FCBRndWriteRecNLT64: Mov DX, Word Ptr ES:[DI+35] FCBRndWriteGotRecN: Push AX Push DX Mov CX, 128 DIV CX Mov Word Ptr ES:[DI+12], AX Mov Byte Ptr ES:[DI+32], DL Pop DX Pop AX Mov BX, Word Ptr ES:[DI+14] XOR CX, CX XCHG AX,SI XCHG AX,DX TEST AX,AX JZ LMul2D MUL BX LMul2D: XCHG AX,CX TEST AX,AX JZ LMul3D MUL SI ADD CX,AX LMul3D: XCHG AX,SI MUL BX ADD DX,CX Mov SI, TablePtr Shl SI, 1 Mov Word Ptr FilePosTbl [SI], AX Mov Word Ptr FilePosTbl [SI+2], DX Call Put_CX_Bytes_From_DSDX Mov R_AX, 2200h Mov CX, R_CX Cmp BytesMoved, CX JE DoFCBRandWrite_8 Mov R_AX, 2201h DoFCBRandWrite_8: LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBRandWrite_AdjLen Add DI, 7 FCBRandWrite_AdjLen: Mov AX, Word Ptr Ctrl_FileLen Mov Word Ptr ES:[DI+16], AX Mov AX, Word Ptr Ctrl_FileLen+2 Mov Word Ptr ES:[DI+18], AX DoFCBRandWrite_8A: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Jmp ExitDOS DoFCBRndWrite_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle FCB File Size Function Call ; ;-----------------------------------------------------------------; DoFCBFileSize: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_DX, DX Mov CS:R_DS, DS Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD DoFCBFileSize_0: Mov R_AX, 0 Call ParseFCBName Mov DX, Offset NameBuffer Mov AL, RD_ONLY CallDOS OpenOp JNC DoFCBFileSize_1 Jmp DoFCBFileSize_9 DoFCBFileSize_1: Mov CurrHandle, AX Call GetOldPID Call ReadFootPrint JNC DoFCBFileSize_3 Mov BX, CurrHandle CallDOS CloseOp Jmp DoFCBFileSize_9 DoFCBFileSize_3: Mov AX, CurrHandle Mov GetCtrlHandle, AX Mov AX, OldPID Mov GetCtrlPID, AX Call GetControlRec Mov AX, Word Ptr Ctrl_FileLen Mov DX, Word Ptr Ctrl_FileLen+2 LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBFileSizeNotExt Add DI, 7 FCBFileSizeNotExt: Mov BP, 0 Mov BX, Word Ptr ES:[DI+14] Call LongDiv Mov Word Ptr ES:[DI+33], AX Cmp Word Ptr ES:[DI+14], 64 JB FCBFileSizeLT64 Mov Byte Ptr ES:[DI+35], DL Jmp FCBFileSize_7 FCBFileSizeLT64: Mov Word Ptr ES:[DI+35], DX FCBFileSize_7: Mov BX, CurrHandle CallDOS CloseOp DoFCBFileSize_8: Mov R_AX, 2300h CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Jmp ExitDOS DoFCBFileSize_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle FCB Block Read Function Call ; ;-----------------------------------------------------------------; DoFCBBlockRead: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_CX, CX Mov CS:R_DX, DX Mov CS:R_DS, DS Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? ; Call SearchFCBTable JNC DoFCBBlkRead_0 ; it's a skinny file Jmp DoFCBBlkRead_9 ; not one of ours (let DOS do it) DoFCBBlkRead_0: Mov SI, TablePtr Mov AX, FileHandleTbl [SI] Mov CurrHandle, AX Call GetOldPID CallDOS GetDTAOp Mov R_DX, BX Mov R_DS, ES LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBBlkReadNotExt Add DI, 7 FCBBlkReadNotExt: Mov CX, Word Ptr ES:[DI+14] Mov Junk, CX Mov AX, R_CX Mul CX Mov R_CX, AX Mov AX, Word Ptr ES:[DI+33] Cmp Word Ptr ES:[DI+14], 64 JB FCBBlkReadRecNLT64 Xor DX, DX Mov DL, Byte Ptr ES:[DI+35] Jmp FCBBlkReadGotRecN FCBBlkReadRecNLT64: Mov DX, Word Ptr ES:[DI+35] FCBBlkReadGotRecN: Mov BX, Word Ptr ES:[DI+14] XOR CX, CX XCHG AX,SI XCHG AX,DX TEST AX,AX JZ LMul2E MUL BX LMul2E: XCHG AX,CX TEST AX,AX JZ LMul3E MUL SI ADD CX,AX LMul3E: XCHG AX,SI MUL BX ADD DX,CX Mov SI, TablePtr Shl SI, 1 Mov Word Ptr FilePosTbl [SI], AX Mov Word Ptr FilePosTbl [SI+2], DX Call Get_CX_Bytes_To_DSDX Mov R_AX, 2700h Cmp R_CX, 0 JE FCBBlkRead_5 Cmp BytesMoved, 0 JA FCBBlkReadSomeBytes Mov R_AX, 2701h Jmp FCBBlkRead_5 FCBBlkReadSomeBytes: Mov AX, BytesMoved Cmp AX, R_CX JE FCBBlkRead_5 Mov R_AX, 2701h FCBBlkRead_5: Mov AX, BytesMoved Xor DX, DX Div Junk Mov R_CX, AX LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBBlkRead_6 Add DI, 7 FCBBlkRead_6: Cmp Word Ptr ES:[DI+14], 64 JAE FCBBlkRead_6A Add Word Ptr ES:[DI+33], AX Adc Word Ptr ES:[DI+35], 0 Jmp FCBBlkRead_6B FCBBlkRead_6A: Add Word Ptr ES:[DI+33], AX Adc Byte Ptr ES:[DI+35], 0 FCBBlkRead_6B: Mov CX, AX JCXZ FCBBlkRead_8 FCBBlkRead_7: Inc Byte Ptr ES:[DI+32] Cmp Byte Ptr ES:[DI+32], 128 JB FCBBlkRead_7A Mov Byte Ptr ES:[DI+32], 0 Inc Word Ptr ES:[DI+12] FCBBlkRead_7A: Loop FCBBlkRead_7 FCBBlkRead_8: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Mov CX, CS:R_CX Jmp ExitDOS DoFCBBlkRead_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; Handle FCB Block Write Function Call ; ;-----------------------------------------------------------------; DoFCBBlockWrite: Push AX ; save registers Push BX Push CX Push DX Push SI Push DI Push BP Push ES Push DS Mov CS:OldSP, SP Mov CS:OldSS, SS CLI ; use our stack Mov SS, CS:OurSS Mov SP, CS:OurSP STI Mov CS:R_CX, CX Mov CS:FCBOfs, DX Mov CS:FCBSeg, DS Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD ; ; Find out who's calling us, and for what file. ; Is it one of our skinny files? ; Call SearchFCBTable JNC DoFCBBlkWrite_0 ; it's a skinny file Jmp DoFCBBlkWrite_9 ; not one of ours (let DOS do it) DoFCBBlkWrite_0: Mov SI, TablePtr Mov AX, FileHandleTbl [SI] Mov CurrHandle, AX Call GetOldPID CallDOS GetDTAOp Mov R_DX, BX Mov R_DS, ES LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBBlkWriteNotExt Add DI, 7 FCBBlkWriteNotExt: Mov CX, Word Ptr ES:[DI+14] Mov Junk, CX Mov AX, R_CX Mul CX Mov R_CX, AX Mov AX, Word Ptr ES:[DI+33] Cmp Word Ptr ES:[DI+14], 64 JB FCBBlkWriteRecNLT64 Xor DX, DX Mov DL, Byte Ptr ES:[DI+35] Jmp FCBBlkWriteGotRecN FCBBlkWriteRecNLT64: Mov DX, Word Ptr ES:[DI+35] FCBBlkWriteGotRecN: Mov BX, Word Ptr ES:[DI+14] XOR CX, CX XCHG AX,SI XCHG AX,DX TEST AX,AX JZ LMul2F MUL BX LMul2F: XCHG AX,CX TEST AX,AX JZ LMul3F MUL SI ADD CX,AX LMul3F: XCHG AX,SI MUL BX ADD DX,CX Mov SI, TablePtr Shl SI, 1 Mov Word Ptr FilePosTbl [SI], AX Mov Word Ptr FilePosTbl [SI+2], DX Call Put_CX_Bytes_From_DSDX Mov R_AX, 2800h Mov CX, R_CX Cmp BytesMoved, CX JE DoFCBBlkWrite_8 Mov R_AX, 2801h DoFCBBlkWrite_8: LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBBlkWrite_AdjLen Add DI, 7 FCBBlkWrite_AdjLen: Mov AX, Word Ptr Ctrl_FileLen Mov Word Ptr ES:[DI+16], AX Mov AX, Word Ptr Ctrl_FileLen+2 Mov Word Ptr ES:[DI+18], AX DoFCBBlkWrite_8A: Mov AX, BytesMoved Xor DX, DX Div Junk Mov R_CX, AX Cmp Word Ptr ES:[DI+14], 64 JAE FCBBlkWrite_8B Add Word Ptr ES:[DI+33], AX Adc Word Ptr ES:[DI+35], 0 Jmp FCBBlkWrite_8C FCBBlkWrite_8B: Add Word Ptr ES:[DI+33], AX Adc Byte Ptr ES:[DI+35], 0 FCBBlkWrite_8C: Mov CX, AX JCXZ FCBBlkWrite_8F FCBBlkWrite_8D: Inc Byte Ptr ES:[DI+32] Cmp Byte Ptr ES:[DI+32], 128 JB FCBBlkWrite_8E Mov Byte Ptr ES:[DI+32], 0 Inc Word Ptr ES:[DI+12] FCBBlkWrite_8E: Loop FCBBlkWrite_8D FCBBlkWrite_8F: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS ; request satisfied.... Pop ES ; go back to the application Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Mov AX, CS:R_AX Mov CX, CS:R_CX Jmp ExitDOS DoFCBBlkWrite_9: CLI ; restore user's stack Mov SS, CS:OldSS Mov SP, CS:OldSP STI Pop DS Pop ES Pop BP Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX Jmp DefaultDOS ;-----------------------------------------------------------------; ; ; ; Exit back to application, leaving flags/registers ; ; in proper state. ; ; ; ;-----------------------------------------------------------------; ExitDOS: Cmp CS:IOFlag, 0 JNE ErrorEncountered PopF ; discard flags STI CLC ; indicate success Ret 2 ErrorEncountered: Mov AX, 5 BadDOS: PopF ; discard flags STI STC ; indicate failure Ret 2 DOS_Handler EndP ;-----------------------------------------------------------------; ; Check the result of our I/O efforts. ; ;-----------------------------------------------------------------; CheckReadError Proc Near JC SayReadError Cmp AX, CX JNE SayReadError Jmp ChkReadExit SayReadError: Cmp CS:IOFlag, 0 JNE ChkReadExit Push AX Push BX Push CX Push DX Push SI Push DI Push ES Call SaveLine25 Push CS Pop ES Mov IOFlag, 1 Mov DX, 1800h Mov DI, Offset ReadErrorMessage Mov CX, LReadError Call AttrCharOut ReadErrorWait: Mov AH, 0 Int 16h Cmp AL, 0Dh JNE ReadErrorWait Call RestLine25 Pop ES Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX ChkReadExit: Ret CheckReadError EndP ;-----------------------------------------------------------------; CheckWriteError Proc Near JC SayWriteError Cmp AX, CX JNE SayWriteError Jmp ChkWriteExit SayWriteError: Cmp CS:IOFlag, 0 JNE ChkWriteExit Push AX Push BX Push CX Push DX Push SI Push DI Push ES Call SaveLine25 Push CS Pop ES Mov IOFlag, 1 Mov DX, 1800h Mov DI, Offset WriteErrorMessage Mov CX, LWriteError Call AttrCharOut WriteErrorWait: Mov AH, 0 Int 16h Cmp AL, 0Dh JNE WriteErrorWait Call RestLine25 Pop ES Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX ChkWriteExit: Ret CheckWriteError EndP ;-----------------------------------------------------------------; TooManyCheck Proc Near Cmp FileCount, 10 JBE TooManyExit Push AX Push BX Push CX Push DX Push SI Push DI Push ES Call SaveLine25 Push CS Pop ES Mov IOFlag, 1 Mov DX, 1800h Mov DI, Offset TooManyError Mov CX, LTooManyError Call AttrCharOut TooManyWait: Mov AH, 0 Int 16h Cmp AL, 0Dh JNE TooManyWait Call RestLine25 Pop ES Pop DI Pop SI Pop DX Pop CX Pop BX Pop AX STC Ret TooManyExit: CLC Ret TooManyCheck EndP ;-----------------------------------------------------------------; ; Parse FCB name into NameBuffer, and put ; ; length into CreateLength field. ; ;-----------------------------------------------------------------; ParseFCBName Proc Near Mov CreateLength, 0 Mov SI, Offset NameBuffer LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE FCBParse_NotExt Add DI, 7 FCBParse_NotExt: Mov AL, Byte Ptr ES:[DI] Inc DI Cmp AL, 0 JE FCBParseNoDrive Add AL, "A" - 1 FCBParseDrivePart: Mov Byte Ptr [SI], AL Inc CreateLength Inc SI Mov Byte Ptr [SI], ":" Inc CreateLength Inc SI Jmp FCBParseNamePart FCBParseNoDrive: CallDOS CurrentDiskOp Add AL, "A" Jmp FCBParseDrivePart FCBParseNamePart: Mov CX, 8 Push DI FCBParseNxtNameChar: Mov AL, Byte Ptr ES:[DI] Cmp AL, " " JE FCBParseGetExt Mov Byte Ptr [SI], AL Inc CreateLength Inc DI Inc SI Loop FCBParseNxtNameChar FCBParseGetExt: Pop DI Add DI, 8 Mov AL, Byte Ptr ES:[DI] Cmp AL, " " JE FCBParseGotName Mov Byte Ptr [SI], "." Inc CreateLength Inc SI Mov Byte Ptr [SI], AL Inc CreateLength Inc DI Inc SI Mov AL, Byte Ptr ES:[DI] Cmp AL, " " JE FCBParseGotName Mov Byte Ptr [SI], AL Inc CreateLength Inc DI Inc SI Mov AL, Byte Ptr ES:[DI] Cmp AL, " " JE FCBParseGotName Mov Byte Ptr [SI], AL Inc CreateLength Inc SI FCBParseGotName: Mov Byte Ptr [SI], 0 Push DS Pop ES Ret ParseFCBName EndP ;-----------------------------------------------------------------; ; Get CX bytes into buffer pointed to by DS:DX ; ;-----------------------------------------------------------------; Get_CX_Bytes_To_DSDX Proc Near ; ; See if DeComp-Buffer is for this file/PID and file position ; Push DS Pop ES Push R_CX Mov BytesMoved, 0 DoRead_1A: Mov DI, TablePtr Shl DI, 1 Mov AX, Word Ptr FilePosTbl [DI] Mov DX, Word Ptr FilePosTbl [DI+2] Mov Word Ptr CurrFilePos, AX Mov Word Ptr CurrFilePos+2, DX ; Don't go beyond EOF, no matter what the requested bytecount is Push AX Mov AX, CurrHandle Mov GetCtrlHandle, AX Mov AX, OldPID Mov GetCtrlPID, AX Call GetControlRec Pop AX Mov CX, Word Ptr Ctrl_FileLen Mov BX, Word Ptr Ctrl_FileLen+2 Cmp DX, BX JA DoRead_1B JB DoRead_1C Cmp AX, CX JB DoRead_1C DoRead_1B: Mov R_CX, 0 Jmp DoRead_6 DoRead_1C: Sub CX, AX Sbb BX, DX Or BX, BX JNZ DoRead_1_Continue Cmp CX, R_CX JAE DoRead_1_Continue Mov R_CX, CX DoRead_1_Continue: Cmp R_CX, 0 JNE DoRead_1D Jmp DoRead_6 DoRead_1D: Mov BX, MaxBuf Div BX Mov CurrBlock, AX Mov BlockPos, DX Cmp AX, DeCompBlock JNE DoRead_2 Mov AX, OldPID Cmp AX, DeCompPID JNE DoRead_2 Mov AX, CurrHandle Cmp AX, DeCompHandle JNE DoRead_2 Jmp DoRead_3 ; use DeComp Buffer ; ; Read appropriate skinny block and de-compress it. ; DoRead_2: Call GetBlock JNC DoRead_3 Jmp DoRead_6 ; ; Transfer decompressed material into application buffer ; (starting at file pos) until either ; - request is satisfied, or ; - end of block is encountered. ; DoRead_3: Mov EndOfBlock, 0 ; default to "we have it all" Mov CX, R_CX ; set up # bytes to move Mov AX, MaxBuf Sub AX, BlockPos ; calc # chars left in buffer Cmp AX, CX ; is it enough? JAE DoRead_3A ; yes Mov CX, AX ; only move what we have Mov EndOfBlock, 1 ; signal we'll need next block DoRead_3A: Push CX Mov SI, Offset DeCompBuffer Add SI, BlockPos LES DI, ApplBufferPtr Rep MovSB Mov R_DX, DI Pop CX Push DS Pop ES ; ; if we encountered end-of-block before, go back to finish the job. ; DoRead_4: Add BytesMoved, CX ; what we've done so far Sub R_CX, CX ; remainder to move Cmp EndOfBlock, 1 ; need to get next block? JNE DoRead_6 ; no Mov BlockPos, 0 Inc CurrBlock Jmp DoRead_2 ; ; update file-position information ; DoRead_6: Mov CX, BytesMoved Add Word Ptr CurrFilePos, CX Adc Word Ptr CurrFilePos+2, 0 Mov SI, TablePtr Shl SI, 1 Mov AX, Word Ptr CurrFilePos Mov DX, Word Ptr CurrFilePos+2 Mov Word Ptr FilePosTbl [SI], AX Mov Word Ptr FilePosTbl [SI+2], DX Pop R_CX Ret Get_CX_Bytes_To_DSDX EndP ;-----------------------------------------------------------------; ; Put CX bytes from DS:DX buffer to disk ; ;-----------------------------------------------------------------; Put_CX_Bytes_From_DSDX Proc Near Push DS Pop ES Push R_CX Mov BytesMoved, 0 Mov DI, TablePtr Shl DI, 1 Mov AX, Word Ptr FilePosTbl [DI] Mov DX, Word Ptr FilePosTbl [DI+2] Mov Word Ptr CurrFilePos, AX Mov Word Ptr CurrFilePos+2, DX Mov BX, MaxBuf Div BX Mov CurrBlock, AX Mov BlockPos, DX Cmp AX, DeCompBlock JNE DoWrite_2 Mov AX, OldPID Cmp AX, DeCompPID JNE DoWrite_2 Mov AX, CurrHandle Cmp AX, DeCompHandle JNE DoWrite_2 Jmp DoWrite_4 ; use DeComp Buffer ; ; is current file position anywhere inside the file already? ; DoWrite_2: Call GetBlock JNC DoWrite_4 ; ; fill decomp buffer with nulls ; DoWrite_3: Mov DI, Offset DeCompBuffer Mov AX, 0 Mov CX, (MaxBuf/2) Rep StoSW ; ; merge material to be written into DeComp Buffer ; DoWrite_4: Mov EndOfBlock, 0 ; default to "it fits" Mov CX, R_CX ; # bytes to write Mov AX, MaxBuf Sub AX, BlockPos ; bufsize - current position Cmp AX, CX ; # chars left in buffer JAE DoWrite_4A ; buffer is large enough Mov CX, AX ; only move what we can Mov EndOfBlock, 1 ; signal "we'll need next block" DoWrite_4A: Cmp R_CX, 0 JE DoWriteTruncate Mov DeCompDirty, 1 Push CX Mov DI, Offset DeCompBuffer Add DI, BlockPos LDS SI, ApplBufferPtr Rep MovSB Pop CX Push ES Pop DS Mov R_DX, SI ; ; update the stats. do we need another block? ; DoWrite_5: Add BytesMoved, CX Sub R_CX, CX ; keep track of partial blks Cmp EndOfBlock, 1 ; need to continue into nxt blk? JNE DoWrite_6 ; no Mov BlockPos, 0 Inc CurrBlock Jmp DoWrite_2 DoWriteTruncate: Cmp Word Ptr CurrFilePos, 0 JNE DoWriteTrunc2 Cmp Word Ptr CurrFilePos+2, 0 JNE DoWriteTrunc2 Call WriteInitControl Jmp DoWrite_6 DoWriteTrunc2: Mov CX, MaxBuf Sub CX, BlockPos Mov DI, Offset DeCompBuffer Add DI, BlockPos Xor AX, AX Rep StoSB Mov DeCompDirty, 1 Mov DI, Offset Loc_Len_Info Mov AX, 6 Mov CX, CurrBlock Sub CX, PointersStart Inc CX Mul CX Add DI, AX Mov AL, 0FFh Mov CX, Offset EndOfCtrlRec Sub CX, DI Rep StoSB Mov PtrsDirty, 1 Mov AX, Word Ptr CurrFilePos Mov DX, Word Ptr CurrFilePos+2 Jmp DoWrite_7 ; ; update file-position information ; DoWrite_6: Mov CX, BytesMoved Add Word Ptr CurrFilePos, CX Adc Word Ptr CurrFilePos+2, 0 Mov SI, TablePtr Shl SI, 1 Mov AX, Word Ptr CurrFilePos Mov DX, Word Ptr CurrFilePos+2 Mov Word Ptr FilePosTbl [SI], AX Mov Word Ptr FilePosTbl [SI+2], DX Call AlignDupedFiles Cmp DX, Word Ptr Ctrl_FileLen+2 JB DoWrite_8 JA DoWrite_7 Cmp AX, Word Ptr Ctrl_FileLen JBE DoWrite_8 DoWrite_7: Mov Word Ptr Ctrl_FileLen, AX ; new "virtual" Mov Word Ptr Ctrl_FileLen+2, DX ; file length Mov CtrlDirty, 1 DoWrite_8: Pop R_CX Ret Put_CX_Bytes_From_DSDX EndP ;-----------------------------------------------------------------; ; See if FCB name is in FCBTable ; ;-----------------------------------------------------------------; SearchFCBTable Proc Near LES DI, FCBPtr Cmp Byte Ptr ES:[DI], 0FFh JNE SearchFCB_1 Add DI, 7 SearchFCB_1: Mov SI, Offset FCBTable Mov AX, 0 FCBNextNmEntry: Push SI Push DI Mov CX, 6 RepE CmpSW Pop DI Pop SI JNE BumpToNextFCBName Push DS Pop ES Mov FCBTablePtr, SI Shl AX, 1 Mov TablePtr, AX CLC Ret BumpToNextFCBName: Add SI, 12 Inc AX Cmp AX, MaxHandles JB FCBNextNmEntry Push DS Pop ES STC Ret SearchFCBTable EndP ;-----------------------------------------------------------------; ; Put message pointed to by ES:DI out to the screen ; ; on line 25. Use an attribute of black-on-white. ; ; Length of message is in CX. Row/Col in DX. ; ;-----------------------------------------------------------------; AttrCharOut Proc Near ACO_Next: JCXZ ACO_Exit Mov AH, 2 Mov BH, 0 Int 10h Mov AL, Byte Ptr ES:[DI] Push CX Mov AH, 9 Mov BX, 0070h Mov CX, 1 Int 10h Pop CX Dec CX Inc DI Inc DL Jmp ACO_Next ACO_Exit: Ret AttrCharOut EndP ;-----------------------------------------------------------------; ; Save any text on screen line 25. ; ;-----------------------------------------------------------------; SaveLine25 Proc Near Mov AH, 3 Mov BH, 0 Int 10h Mov CPosSave, DX Mov CTypSave, CX Mov SI, 0 Mov DX, 1800h GetFromScrn: Push SI Mov AH, 2 Mov BH, 0 Int 10h Mov AH, 8 Mov BH, 0 Int 10h Pop SI Mov Word Ptr ScreenSave [SI], AX Inc DX Inc SI Inc SI Cmp DX, 184Fh JNE GetFromScrn Ret SaveLine25 EndP ;-----------------------------------------------------------------; ; Restore text on screen line 25. ; ;-----------------------------------------------------------------; RestLine25 Proc Near Mov SI, 0 Mov DX, 1800h PutToScrn: Push SI Mov AH, 2 Mov BH, 0 Int 10h Pop SI Mov AX, Word Ptr ScreenSave [SI] Push SI Mov BL, AH Mov BH, 0 Mov CX, 1 Mov AH, 9 Int 10h Pop SI Inc DX Inc SI Inc SI Cmp DX, 184Fh JNE PutToScrn Mov AH, 1 Mov CX, CTypSave Int 10h Mov DX, CPosSave Mov BH, 0 Mov AH, 2 Int 10h Ret RestLine25 EndP ;-----------------------------------------------------------------; ; ; ; Get a block of skinny material & decompress it ; ; ; ;-----------------------------------------------------------------; GetBlock Proc Near Call PutBlock Mov AdvancePtr, 0 Mov AX, CurrBlock Mov DeCompBlock, AX Mov AX, OldPID Mov DeCompPID, AX Mov AX, CurrHandle Mov DeCompHandle, AX Mov AX, CurrHandle Mov GetCtrlHandle, AX Mov GetPtrsHandle, AX Mov AX, OldPID Mov GetCtrlPID, AX Mov GetPtrsPID, AX Call GetControlRec ; for filelength Mov AX, CurrBlock Mov PointerBlock, AX Call GetPointerRec ; based on CurrBlock GetBlock_1: Mov BX, Offset Loc_Len_Info ; get block position Mov AX, 6 Mov SI, CurrBlock Sub SI, PointersStart Mul SI Add BX, AX Mov DX, Word Ptr [BX] ; location low word Mov CX, Word Ptr [BX+2] ; location high word Mov SI, Word Ptr [BX+4] ; length Cmp SI, 0FFFFh ; valid entry? JNE GetBlock_2 ; yes BlockNotFound: STC Ret ; - - - - - - - - - - - - - - - - - - - - - - - - GetBlock_2: Mov AX, 0 Mov BX, CurrHandle CallDOS SeekOp ; seek to skinny block Mov CX, SI ; remember length Mov BX, CurrHandle ; read skinny block Mov DX, Offset DeCompBuffer CallDOS ReadOp Call CheckReadError Mov DI, Offset IOBuffer Add DI, AdvancePtr Mov SI, Offset DeCompBuffer+6 Sub CX, 6 Add AdvancePtr, CX Rep MovSB ; ; now get any "extents" that belong to this compressed material ; LookAtLink: Cmp ILinkLen, 0FFFFh ; last in chain? JE DeCompressThisBlock ; yes Mov CX, Word Ptr ILinkPtr+2 Mov DX, Word Ptr ILinkPtr Mov SI, ILinkLen Jmp GetBlock_2 DecompressThisBlock: Mov Prefix_Code, 0 Mov Free_Code, First_Free Mov Max_Code, K512 Mov NBits, K9 Mov K, 0 Mov Bit_Offset, 0 Mov Input_Offset, 0 Mov Input_Size, MaxBuf Mov Cur_Code, 0 Mov Old_Code, 0 Mov In_Code, 0 Mov Stack_Count, 0 Mov Fin_Char, 0 Mov Output_Offset, 0 Mov DI, Offset Hash Mov CX, (maxmax * 5) / 2 Xor AX, AX Rep StoSW Call DeCompress ; IOBuffer --> DeCompBuffer CLC Ret GetBlock EndP ;-----------------------------------------------------------------; ; Compress DeCompBuffer into IOBuffer and write ; ; IOBuffer out to disk. ; ;-----------------------------------------------------------------; PutBlock Proc Near Cmp DeCompDirty, 1 JE DoWriteTheBlock Ret DoWriteTheBlock: Mov Prefix_Code, 0 Mov Free_Code, 0 Mov Max_Code, K512 Mov NBits, K9 Mov K, 0 Mov Bit_Offset, 0 Mov Input_Offset, 0 Mov Input_Size, MaxBuf Mov Cur_Code, 0 Mov Old_Code, 0 Mov In_Code, 0 Mov Stack_Count, 0 Mov Fin_Char, 0 Mov Output_Offset, 0 Mov DI, Offset Hash Mov CX, (maxmax * 5) / 2 Xor AX, AX Rep StoSW Call Compress ; DeCompBuf --> IOBuf+6 Mov AX, DeCompHandle Mov GetCtrlHandle, AX Mov GetPtrsHandle, AX Mov AX, DeCompPID Mov GetCtrlPID, AX Mov GetPtrsPID, AX Call GetControlRec Mov AX, DeCompBlock Mov PointerBlock, AX Call GetPointerRec Mov BX, Offset Loc_Len_Info ; get block position Mov AX, 6 Mov SI, DeCompBlock Sub SI, PointersStart Mul SI Add BX, AX Mov PtrRecSegment, BX Mov DX, Word Ptr [BX] ; location low word Mov CX, Word Ptr [BX+2] ; location high word Mov SI, Word Ptr [BX+4] ; length Mov Word Ptr CurrPtr, DX Mov Word Ptr CurrPtr+2, CX Mov CurrLen, SI Mov AX, Offset IOBuffer+6 Mov AdvancePtr, AX Mov AX, CompressLength Mov LenToWrite, AX PutBlock_1: Cmp LenToWrite, 0 JNE PutBlock_2 PutBlockExit: Mov DeCompDirty, 0 Ret PutBlock_2: Cmp Word Ptr CurrPtr+2, 0FFFFh JE PutBlock_3 Sub CurrLen, 6 Mov DX, Word Ptr CurrPtr Mov CX, Word Ptr CurrPtr+2 Mov BX, DeCompHandle Mov AL, 0 CallDOS SeekOp Mov BX, DeCompHandle Mov CX, 6 Mov DX, Offset IOBuffer CallDOS ReadOp Call CheckReadError Mov AX, Word Ptr OLinkPtr Mov Word Ptr NextPtr, AX Mov AX, Word Ptr OLinkPtr+2 Mov Word Ptr NextPtr+2, AX Mov AX, OLinkLen Mov NextLen, AX Jmp PutBlock_4 PutBlock_3: Mov CX, 0 Mov DX, CX Mov AL, 2 Mov BX, DeCompHandle CallDOS SeekOp Mov CX, DX Mov DX, AX Mov Word Ptr CurrPtr, DX Mov Word Ptr CurrPtr+2, CX Mov AX, LenToWrite Mov CurrLen, AX Mov BX, PtrRecSegment Cmp Word Ptr [BX+2], 0FFFFh JNE PutBlock_3A Mov Word Ptr [BX], DX Mov Word Ptr [BX+2], CX Add AX, 6 Mov Word Ptr [BX+4], AX Mov PtrsDirty, 1 Jmp PutBlock_3B PutBlock_3A: Mov DX, Word Ptr PrevPtr Mov CX, Word Ptr PrevPtr+2 Mov BX, DeCompHandle Mov AL, 0 CallDOS SeekOp Mov AX, Word Ptr CurrPtr Mov Word Ptr OLinkPtr, AX Mov AX, Word Ptr CurrPtr+2 Mov Word Ptr OLinkPtr+2, AX Mov AX, CurrLen Add AX, 6 Mov OLinkLen, AX Mov BX, DeCompHandle Mov CX, 6 Mov DX, Offset IOBuffer CallDOS WriteOp Call CheckWriteError PutBlock_3B: Mov Word Ptr NextPtr, 0FFFFh Mov Word Ptr NextPtr+2, 0FFFFh Mov NextLen, 0FFFFh PutBlock_4: Mov DX, Word Ptr CurrPtr Mov Word Ptr PrevPtr, DX Mov CX, Word Ptr CurrPtr+2 Mov Word Ptr PrevPtr+2, CX Mov BX, DeCompHandle Mov AL, 0 CallDOS SeekOp Mov SI, AdvancePtr Mov AX, Word Ptr NextPtr Mov Word Ptr [SI-6], AX Mov AX, Word Ptr NextPtr+2 Mov Word Ptr [SI-4], AX Mov AX, NextLen Mov Word Ptr [SI-2], AX Mov AX, LenToWrite Cmp AX, CurrLen JAE PutBlock_5 Mov CurrLen, AX PutBlock_5: Mov DX, AdvancePtr Sub DX, 6 Mov CX, CurrLen Add CX, 6 Mov BX, DeCompHandle CallDOS WriteOp Call CheckWriteError Mov AX, CurrLen Sub LenToWrite, AX Add AdvancePtr, AX Mov DX, Word Ptr NextPtr Mov Word Ptr CurrPtr, DX Mov CX, Word Ptr NextPtr+2 Mov Word Ptr CurrPtr+2, CX Mov AX, NextLen Mov CurrLen, AX Jmp PutBlock_1 PutBlock EndP ;-----------------------------------------------------------------; ; Get the control record, if necessary ; ;-----------------------------------------------------------------; GetControlRec Proc Near Push AX Push BX Push CX Push DX Mov AX, GetCtrlPID Cmp AX, CtrlPID JNE ReadTheCtrlRec Mov AX, GetCtrlHandle Cmp AX, CtrlHandle JNE ReadTheCtrlRec Jmp AlreadyHaveCtrl ReadTheCtrlRec: Call WriteTheCtrlRec Mov AX, GetCtrlHandle Mov CtrlHandle, AX Mov AX, GetCtrlPID Mov CtrlPID, AX Mov CX, 0 ; get control record Mov DX, CX ; from beginning of file Mov AX, CX Mov BX, CtrlHandle CallDOS SeekOp Mov CX, CtrlSize Mov BX, CtrlHandle Mov DX, Offset CtrlBuffer CallDOS ReadOp Call CheckReadError AlreadyHaveCtrl: Pop DX Pop CX Pop BX Pop AX Ret GetControlRec EndP ;-----------------------------------------------------------------; ; Write the control record to the beginning of the file ; ;-----------------------------------------------------------------; WriteTheCtrlRec Proc Near Cmp CtrlDirty, 0 JE WriteCtrlExit Push AX Push BX Push CX Push DX Mov CX, 0 ; seek to beginning of file Mov DX, CX Mov AL, 0 Mov BX, CtrlHandle CallDOS SeekOp Mov BX, CtrlHandle ; re-write control record Mov DX, Offset CtrlBuffer Mov CX, CtrlSize CallDOS WriteOp Call CheckWriteError Mov CtrlDirty, 0 Pop DX Pop CX Pop BX Pop AX WriteCtrlExit: Ret WriteTheCtrlRec EndP ;-----------------------------------------------------------------; ; Get the pointer record that corresponds to the ; ; block # in PointerBlock. ; ;-----------------------------------------------------------------; GetPointerRec Proc Near Push AX Push BX Push CX Push DX Mov BX, GetPtrsPID Cmp BX, PtrsPID JNE Read1stPtrsRec Mov BX, GetPtrsHandle Cmp BX, PtrsHandle JNE Read1stPtrsRec Jmp GetRightPointers Read1stPtrsRec: Call WritePointerRec Mov AX, GetPtrsHandle Mov PtrsHandle, AX Mov AX, GetPtrsPID Mov PtrsPID, AX Mov CX, 0 ; get first pointers record Mov DX, 16 Mov AX, 0 Mov BX, PtrsHandle CallDOS SeekOp Mov Word Ptr PtrsFilePos, AX Mov Word Ptr PtrsFilePos+2, DX Mov CX, PtrsSize Mov BX, PtrsHandle Mov DX, Offset Ctrl_Pointers CallDOS ReadOp Call CheckReadError Mov PointersStart, 0 Mov PointersEnd, NumPtrs-1 GetRightPointers: Mov AX, PointerBlock Cmp AX, PointersStart JB ChainBack Jmp LastPtrTest ChainBack: Call WritePointerRec Mov CX, Word Ptr Ctrl_Prev+2 ; chain backwards Mov DX, Word Ptr Ctrl_Prev Mov BX, PtrsHandle Mov AL, 0 CallDOS SeekOp Mov DX, Offset Ctrl_Pointers Mov BX, PtrsHandle Mov CX, PtrsSize CallDOS ReadOp Call CheckReadError Sub PointersStart, NumPtrs Sub PointersEnd, NumPtrs Jmp GetRightPointers LastPtrTest: Mov AX, PointerBlock Cmp AX, PointersEnd JA ChainForwards Jmp GotRightPointers ChainForwards: Call WritePointerRec Mov CX, Word Ptr Ctrl_Next+2 ; chain forwards Mov DX, Word Ptr Ctrl_Next Cmp CX, 0 JNE ChainNext Cmp DX, 0 JNE ChainNext Jmp CreateNewPointers ChainNext: Mov BX, PtrsHandle Mov AL, 0 CallDOS SeekOp Mov Word Ptr PtrsFilePos, AX Mov Word Ptr PtrsFilePos+2, DX Mov DX, Offset Ctrl_Pointers Mov BX, PtrsHandle Mov CX, PtrsSize CallDOS ReadOp Call CheckReadError Add PointersStart, NumPtrs Add PointersEnd, NumPtrs Jmp GetRightPointers CreateNewPointers: Push Word Ptr PtrsFilePos Push Word Ptr PtrsFilePos+2 Mov CX, 0 ; seek to end of file Mov DX, CX Mov AL, 2 Mov BX, PtrsHandle CallDOS SeekOp Mov Word Ptr Ctrl_Next+2, DX Mov Word Ptr Ctrl_Next, AX Mov PtrsDirty, 1 Call WritePointerRec Mov DI, Offset Ctrl_Pointers Mov AX, 0 Mov CX, 8 Rep StoSW Mov AX, 0FFFFh Mov CX, (PtrsSize / 2) - 8 Rep StoSW Pop Word Ptr Ctrl_Prev+2 Pop Word Ptr Ctrl_Prev Mov AX, GetPtrsHandle Mov PtrsHandle, AX Mov AX, GetPtrsPID Mov PtrsPID, AX Mov CX, 0 ; seek to end of file Mov DX, CX Mov AL, 2 Mov BX, PtrsHandle CallDOS SeekOp Mov Word Ptr PtrsFilePos, AX Mov Word Ptr PtrsFilePos+2, DX Add PointersStart, NumPtrs Add PointersEnd, NumPtrs Mov PtrsDirty, 1 Call WritePointerRec GotRightPointers: Pop DX Pop CX Pop BX Pop AX Ret GetPointerRec EndP ;-----------------------------------------------------------------; ; Write the current pointer record. ; ;-----------------------------------------------------------------; WritePointerRec Proc Near Cmp PtrsDirty, 0 JE WritePtrsExit Push AX Push BX Push CX Push DX Mov CX, Word Ptr PtrsFilePos+2 Mov DX, Word Ptr PtrsFilePos Mov AX, 0 Mov BX, PtrsHandle CallDOS SeekOp Mov BX, PtrsHandle Mov DX, Offset Ctrl_Pointers Mov CX, PtrsSize CallDOS WriteOp Call CheckWriteError Mov PtrsDirty, 0 Pop DX Pop CX Pop BX Pop AX WritePtrsExit: Ret WritePointerRec EndP ;-----------------------------------------------------------------; ; if handled dup'd, make file pos the same for both. ; ;-----------------------------------------------------------------; AlignDupedFiles Proc Near Push AX Push BX Push SI Push DI Mov SI, TablePtr Mov DI, DupeTable [SI] Cmp DI, 0FFFFh JE AlignExit Shl DI, 1 Shl SI, 1 Mov AX, Word Ptr FilePosTbl [SI] Mov BX, Word Ptr FilePosTbl+2 [SI] Mov Word Ptr FilePosTbl [DI], AX Mov Word Ptr FilePosTbl+2 [DI], BX AlignExit: Pop DI Pop SI Pop BX Pop AX Ret AlignDupedFiles EndP ;-----------------------------------------------------------------; ; Get a buffer of Diet.Dir bytes into ; ; 'ScreenSave'. ; ;-----------------------------------------------------------------; FGetBuff Proc Near FGB1: Mov SI, fbufndx Cmp SI, fbufbytes JAE FGB2 Mov AL, ScreenSave[SI] Inc fbufndx Jmp Short FGB_Exit FGB2: Mov DX, Offset ScreenSave Mov BX, DietDirHandle Mov CX, 160 CallDOS ReadOp JC FGB_Eof Cmp AX, 0 JE FGB_Eof Mov fbufbytes, AX Mov fbufndx, 0 Jmp Short FGB1 FGB_Eof: Mov fbufndx, MaxTextBuf Mov AL, 0FFh FGB_Exit: Ret FGetBuff EndP ;-----------------------------------------------------------------; ; ; ; Switch DTAs before parsing Diet.Dir ; ; ; ;-----------------------------------------------------------------; UseOurDTA Proc Near CallDOS GetDTAOp Mov OldDTAOfs, BX Mov OldDTASeg, ES Push DS LDS DX, OurDTA CallDOS SetDTAOp Pop DS Push DS Pop ES Ret UseOurDTA EndP SetOldDTA Proc Near Push DS LDS DX, OldDTA CallDOS SetDTAOp Pop DS Ret SetOldDTA EndP ;-----------------------------------------------------------------; ; Search 'DIET.DIR' for this file name ; ; Return Carry-True if file not found ; ;-----------------------------------------------------------------; SearchDietDir Proc Near Call UseOurDTA Call SetOurPID Mov DietEOF, 0 Call Parse_DS_DX_Name Call TooManyCheck JNC Search_0 Jmp Short JustGoAway Search_0: Mov DX, Offset DietPath Mov AL, RD_ONLY CallDOS OpenOp JNC Search_1 JustGoAway: Call SetOldDTA Call SetOldPID STC Ret Search_1: Mov DietDirHandle, AX Mov fbufbytes, 0 Mov fbufndx, MaxTextBuf Search_2A: Mov AL, 0 Mov CX, MaxName Mov DI, Offset NameBuffer Rep StoSB Mov CharPos, 0 Search_2: Call FGetBuff ; get a byte of DietDir ; into AL Search_TestEOF: Cmp AL, 0FFh ; EOF? JNE Search_3 Mov DietEOF, 1 ; no more input Jmp Search_4 ; go look at last name Search_3: Cmp AL, 10 JE Search_2 Cmp AL, 26 JE Search_2 Mov SI, CharPos Cmp AL, 13 JE Search_3C Mov NameBuffer[SI], AL Cmp CharPos, MaxName-1 JE Search_4 Inc CharPos ; go get next char Jmp Search_2 Search_3C: Mov NameBuffer[SI], 0 Jmp Search_4 ;- - - - - - - - - - - - - - - - - - - - - - - GoBackToSearch_2A: Jmp Search_2A ; a local jumping place Search_4: Mov AX, CharPos XChg AH, AL Or AX, DietEOF Cmp AX, 0001h ; EOF and empty line? JE Search_9 Cmp AH, 0 ; empty line? JE GoBackToSearch_2A Cmp NameBuffer, ' ' ; if first char is blank, JE GoBackToSearch_2A ; ignore line Cmp NameBuffer, ';' ; do the same if it starts JE GoBackToSearch_2A ; with a semicolon Call IsThisIt ; is this line of Diet.Dir JNC Search_5 ; the filename being created? Cmp DietEOF, 1 ; are we all done looking? JE Search_9 Jmp Search_2A ; no, go read another line Search_5: Mov BX, DietDirHandle CallDOS CloseOp Call SetOldDTA Call SetOldPID CLC Ret Search_9: Mov BX, DietDirHandle CallDOS CloseOp Call SetOldDTA Call SetOldPID STC Ret SearchDietDir EndP ;-----------------------------------------------------------------; ; Turn DS:DX path/file name into something ; ; we can compare against. Put resulting filename ; ; in CreateName and put length in CreateLength. ; ;-----------------------------------------------------------------; Parse_DS_DX_Name Proc Near Push DS Pop ES Mov AL, 0 Mov CX, MaxName Mov DI, Offset CreateName Rep StoSB LES DI, CreatePtr ; calc length of DSDX name Mov BX, DI Mov CX, MaxName Mov AL, 0 RepNE ScaSB Sub DI, BX Mov CreateLength, DI Mov SI, Offset CreateName LES DI, CreatePtr ; old ds:dx pointer Cmp Byte Ptr ES:[DI+1], ':' JE ParseDSDX_Drive CallDOS CurrentDiskOp ; generate <d>: Add AL, "A" Mov AH, ":" Jmp ParseDSDX_GetName ParseDSDX_Drive: Mov AX, Word Ptr ES:[DI] ; pick up <d>: Inc DI Inc DI Dec CreateLength Dec CreateLength Cmp AL, '_' JBE ParseDSDX_GetName And AL, '_' ParseDSDX_GetName: Mov Word Ptr CreateName, AX Inc SI Inc SI Push ES ; save modified CreatePtr Push DI Cmp Byte Ptr ES:[DI], '\' ; do we need cwd? JE ParseDSDX_DoRemainder ; no Push DS Pop ES Mov Byte Ptr [SI], '\' Inc SI Mov DL, Byte Ptr CreateName Sub DL, '@' CallDOS GetCurrDir Mov DI, Offset CreateName Mov CX, MaxName Mov AL, 0 RepNE ScaSB Dec DI Mov SI, DI Cmp Byte Ptr [SI-1], '\' JE ParseDSDX_DoRemainder Mov Byte Ptr [SI], '\' Inc SI ParseDSDX_DoRemainder: Mov CX, CreateLength Mov AX, DS Mov BX, SI Pop SI ; recover modified CreatePtr Pop DS Mov ES, AX Mov DI, BX Rep MovSB Mov Byte Ptr ES:[DI], 0 Push CS ; restore addressability Pop DS Push DS Pop ES Mov DI, Offset CreateName Mov BX, DI Mov CX, MaxName Mov AL, 0 RepNE ScaSB Mov CX, DI Dec CX Sub CX, BX Mov CreateLength, CX STD Mov CX, MaxName Mov AL, '\' RepNE ScaSB CLD Inc DI Inc DI Sub DI, BX Mov DirLength, DI Ret Parse_DS_DX_Name EndP ;-----------------------------------------------------------------; ; See if NameBuffer (from DIET.DIR) is the same as ; ; the filename just created. Return Carry-Clear if equal. ; ;-----------------------------------------------------------------; IsThisIt Proc Near Mov DI, Offset NameBuffer Mov SI, Offset CreateName Mov CX, DirLength ; directory names must match exactly fmd1: mov al,byte ptr [si] cmp al,'_' jbe fmd2 and al,'_' fmd2: mov bl,byte ptr [di] cmp bl,'_' jbe fmd3 and bl,'_' fmd3: cmp al,bl je fmd4 cmp bl, '=' jne no_dir_match clc jmp fm1 no_dir_match: stc jmp fm1 fmd4: inc si inc di loop fmd1 ; do the filename portion separately from the extension fm2: mov al,byte ptr [si] cmp al,'\' je fm11 cmp al,'_' jbe fm3 and al,'_' fm3: mov bl,byte ptr [di] cmp bl,'\' je fm11 cmp bl,'_' jbe fm4 and bl,'_' fm4: cmp bl,'*' jne fm5 inc di fm6: cmp byte ptr [si],0 je fm8 cmp byte ptr [si],'.' je fm8 inc si jmp short fm6 fm5: cmp al,0 je fm8 cmp bl,0 je fm8 cmp al,'.' je fm8 cmp bl,'.' je fm8 fm9: cmp al,bl je fm12 cmp bl,'?' jne fm11 fm12: inc si inc di jmp fm2 fm11: stc jmp fm1 ; now do the extension fm8: mov al,byte ptr [si] cmp al,'_' jbe fm13 and al,'_' fm13: mov bl,byte ptr [di] cmp bl,'_' jbe fm14 and bl,'_' fm14: cmp al,'.' jne fm15 inc si jmp short fm8 fm15: cmp bl,'.' jne fm16 inc di jmp short fm8 fm16: cmp bl,'*' jne fm17 clc jmp short fm1 fm17: cmp al,0 jne fm18 cmp bl,0 jne fm19 clc jmp short fm1 jmp short fm18 fm19: stc jmp short fm1 fm18: cmp bl,0 jne fm21 stc jmp short fm1 fm21: cmp al,bl je fm23 cmp bl,'?' jne fm22 fm23: inc si inc di jmp fm8 fm22: stc fm1: ret IsThisIt Endp ;-----------------------------------------------------------------; ; Write initial Control Record ; ;-----------------------------------------------------------------; WriteInitControl Proc Near Call WriteTheCtrlRec Call WritePointerRec ; empty out previous rcds. Mov AX, CurrHandle Mov CtrlHandle, AX Mov AX, OldPID Mov CtrlPID, AX Mov SI, Offset Control_ZM ; footprint, filelength Mov DI, Offset CtrlBuffer Mov CX, Ctrl_ZM_Size / 2 Rep MovSW Mov CtrlDirty, 1 Call WriteTheCtrlRec Mov DI, Offset Ctrl_Pointers Mov AX, 0 Mov CX, 8 Rep StoSW Mov AX, 0FFFFh Mov CX, (PtrsSize / 2) - 8 Rep StoSW Mov AX, CurrHandle Mov PtrsHandle, AX Mov AX, OldPID Mov PtrsPID, AX Mov Word Ptr PtrsFilePos, 16 Mov Word Ptr PtrsFilePos+2, 0 Mov PointersStart, 0 Mov PointersEnd, NumPtrs-1 Mov PtrsDirty, 1 Call WritePointerRec Mov DX, Offset CtrlBuffer ; now truncate file length Mov BX, PtrsHandle Mov CX, 0 CallDOS WriteOp Call CheckWriteError Ret WriteInitControl EndP ;-----------------------------------------------------------------; ; Read ctrl rec, if present, to determine if file skinny. ; ; Return Carry-Clear if it's a skinny file. ; ;-----------------------------------------------------------------; ReadFootPrint Proc Near Mov CritFlag, 0 Mov AL, 24h CallDOS GetVectorOp Mov Int24Ofs, BX Mov Int24Seg, ES Push CS Pop ES Mov AL, 24h Mov DX, Offset ISR24 CallDOS SetVectorOp Call TooManyCheck JC ReadCtrlFailed Mov BX, CurrHandle Mov AX, 0 CallDOS IOCTL Test CritFlag, 1 JNZ ReadCtrlFailed Test DL, 80h JNZ ReadCtrlFailed Mov BX, CurrHandle ; file just opened...is Mov CX, 16 ; already at beginning Mov DX, Offset FootBuffer ; read just 16 bytes CallDOS ReadOp JC ReadCtrlFailed ; file I/O error. Test CritFlag, 1 JNZ ReadCtrlFailed Push CX Push AX Mov AX, 0 ; position file back at beginning Mov CX, 0 Mov DX, CX Mov BX, CurrHandle CallDOS SeekOp Test CritFlag, 1 JNZ ReadCtrlFailed Pop AX Pop CX Cmp AX, CX JNE ReadCtrlFailed ; file too short ; (no ctrl record) Mov SI, Offset Control_ZM Mov DI, Offset FootBuffer Mov CX, 3 RepE CmpSW JNE ReadCtrlFailed ; footprint not there. Jmp ReadCtrlOkay ; it's one of ours! ReadCtrlFailed: Mov AL, 24h Mov DX, Int24Ofs Mov DS, Int24Seg CallDOS SetVectorOp Push CS Pop DS Mov CritFlag, 0 STC Ret ReadCtrlOkay: Mov AL, 24h Mov DX, Int24Ofs Mov DS, Int24Seg CallDOS SetVectorOp Push CS Pop DS Mov CritFlag, 0 CLC Ret ReadFootPrint EndP ;-----------------------------------------------------------------; ; Store file handle, etc. for this skinny file ; ;-----------------------------------------------------------------; RememberThisFile Proc Near Call SearchTable Mov BX, TablePtr Mov AX, CurrHandle Mov FileHandleTbl [BX], AX Mov AX, OldPID Mov PIDTbl [BX], AX Shl BX, 1 Mov Word Ptr FilePosTbl [BX], 0 ; dbl-word-sized Mov Word Ptr FilePosTbl [BX+2], 0 Inc FileCount Ret RememberThisFile EndP ;-----------------------------------------------------------------; ; Un-Store file handle, etc....file is now closed ; ;-----------------------------------------------------------------; ForgetThisFile Proc Near Mov BX, TablePtr Mov AX, FileHandleTbl [BX] Mov FileHandleTbl [BX], 0FFFFh ; mark table Mov PIDTbl [BX], 0FFFFh ; entries as empty Mov SI, BX Mov DI, DupeTable [SI] Cmp DI, 0FFFFh JE Forget_1 Mov DupeTable [SI], 0FFFFh Mov DupeTable [DI], 0FFFFh Forget_1: Shl BX, 1 Mov Word Ptr FilePosTbl [BX], 0 Mov Word Ptr FilePosTbl [BX+2], 0 Forget_2: Cmp AX, CtrlHandle JNE Forget_3 Mov CtrlHandle, 0FFFFh Forget_3: Cmp AX, PtrsHandle JNE Forget_4 Mov PtrsHandle, 0FFFFh Forget_4: Cmp AX, DeCompHandle JNE Forget_9 Mov DeCompHandle, 0FFFFh Forget_9: Cmp FileCount, 0 JE ForgetExit Dec FileCount ForgetExit: Ret ForgetThisFile EndP ;-----------------------------------------------------------------; ; Find this handle/PID in table (or find 1st free element) ; ; ; ; If found, return TablePtr = that location and return ; ; Carry-Clear. ; ; ; ; If not found, return TablePtr = first free position ; ; and Carry-Set. ; ;-----------------------------------------------------------------; SearchTable Proc Near Mov AX, 0FFFFh Mov DI, Offset FileHandleTbl Mov BP, DI Mov CX, MaxHandles Push CX Push DI RepNE ScaSW Dec DI Dec DI Sub DI, BP Mov TablePtr, DI Pop DI Pop CX Mov AX, CurrHandle RepNE ScaSW JNE SearchTable_8 Dec DI Dec DI Sub DI, BP Mov AX, OldPID Cmp AX, PIDTbl [DI] JNE SearchTable_8 Mov TablePtr, DI CLC Ret SearchTable_8: STC Ret SearchTable EndP ;-----------------------------------------------------------------; ; Save the application PID ; ;-----------------------------------------------------------------; GetOldPID Proc Near Xor AX, AX ;to get PSP from DOS CallDOS 51h ;current PSP now in BX Mov OldPID, BX ;save it Ret GetOldPID EndP ;-----------------------------------------------------------------; ; Tell DOS to use our PID ; ;-----------------------------------------------------------------; SetOurPID Proc Near Mov BX, OurPID ;set our PSP instead Xor AX, AX CallDOS 50h Ret SetOurPID EndP ;-----------------------------------------------------------------; ; Tell DOS to resume using the application PID ; ;-----------------------------------------------------------------; SetOldPID Proc Near Mov BX, OldPID Xor AX, AX CallDOS 50h Ret SetOldPID EndP ;-----------------------------------------------------------------; ; ; ; The actual DECOMPRESS logic ; ; A simple implementation of Lempel-Ziv-Welch ; ; ; ;-----------------------------------------------------------------; DeCompress Proc Near d1: call read_code cmp ax,eof jne d2 d1a: ret d2: cmp ax,clear jne d7 mov nbits,K9 mov max_code,K512 mov free_code,first_free call read_code mov cur_code,ax mov old_code,ax mov k,al mov fin_char,al mov al,k call write_char jmp d1 d7: mov cur_code,ax mov in_code,ax cmp ax,free_code jl d11 mov ax,old_code mov cur_code,ax mov al,fin_char push ax inc stack_count d11: cmp cur_code,255 jle d15 mov bx,cur_code mov al, char [bx] push ax inc stack_count shl bx, 1 mov ax, next [bx] mov cur_code,ax jmp d11 d15: mov ax,cur_code mov fin_char,al mov k,al push ax inc stack_count mov cx,stack_count jcxz d18 d17: pop ax call write_char loop d17 d18: mov stack_count,cx call d_add_code mov ax,in_code mov old_code,ax mov bx,free_code cmp bx,max_code jl d23 cmp nbits,K10 je d23 inc nbits shl max_code,1 d23: jmp d1 DeCompress EndP read_code proc near mov ax,bit_offset add ax,nbits xchg bit_offset,ax mov cx,8 xor dx,dx div cx drd0: add ax,offset IOBuffer mov si,ax lodsw mov bx,ax lodsb mov cx,dx jcxz drd2 drd1: shr al,1 rcr bx,1 loop drd1 drd2: mov ax,bx mov bx,nbits sub bx,K9 shl bx,1 and ax,masks[bx] ret read_code endp write_char proc near mov di,output_offset lea di,DeCompBuffer[di] stosb inc output_offset ret write_char endp d_add_code proc near mov bx,free_code mov al,k mov char [bx],al mov ax,old_code shl bx,1 mov next [bx],ax inc free_code ret d_add_code endp ;-----------------------------------------------------------------; ; ; ; The actual COMPRESS logic ; ; A simple implementation of Lempel-Ziv-Welch ; ; ; ;-----------------------------------------------------------------; Compress Proc Near l1: call init_table mov ax,clear call write_code call read_char l4: xor ah,ah l4a: mov prefix_code,ax call read_char jc l17 mov k,al mov bx,prefix_code call lookup_code jnc l4a call add_code push bx mov ax,prefix_code call write_code pop bx mov al,k cmp bx,max_code jl l4 cmp nbits,K10 jl l14 mov ax,clear call write_code call init_table mov al,k jmp l4 l14: inc nbits shl max_code,1 jmp l4 l17: mov ax,prefix_code call write_code mov ax,eof call write_code mov ax,bit_offset cmp ax,0 je l17a mov cx,8 xor dx,dx div cx or dx,dx je l17a inc ax l17a: mov CompressLength, ax ret Compress EndP init_table proc near mov nbits,K9 mov max_code,K512 mov ax,-1 mov cx, K256 mov di,offset next rep stosw mov cx, K256 mov di,offset first rep stosw mov cx, K256 / 2 mov di,offset char rep stosw mov free_code,first_free ret init_table endp write_code proc near push ax mov ax,bit_offset mov cx,nbits add bit_offset,cx mov cx,8 xor dx,dx div cx add ax,offset IOBuffer+6 mov di,ax pop ax mov cx,dx xor dx,dx jcxz wc3 wc2: shl ax,1 rcl dx,1 loop wc2 or al,byte ptr [di] wc3: stosw mov al,dl stosb ret write_code endp read_char proc near mov di,input_offset cmp di,input_size jl rd1 stc ret rd1: lea si,DeCompBuffer[di] lodsb inc input_offset clc ret read_char endp lookup_code proc near mov si,bx shl si,1 mov di,0 cmp first [si],-1 je gc4 inc di mov bx,first [si] gc2: mov si,bx shl si,1 cmp char [bx],al jne gc3 clc mov ax,bx ret gc3: cmp next [si],-1 je gc4 mov bx,next [si] jmp gc2 gc4: stc ret lookup_code endp add_code proc near mov bx,free_code cmp di,0 je ac1 mov next [si],bx jmp short ac2 ac1: mov first [si],bx ac2: cmp bx,maxmax je ac3 mov si,bx shl si,1 mov first [si],-1 mov next [si],-1 mov char [bx],al inc free_code ac3: ret add_code endp ;-----------------------------------------------------------------; ; Subroutine for doing long division ; ; dividend in DX:AX ; ; divisor in BP:BX ; ; quotient placed in DX:AX ; ;-----------------------------------------------------------------; LongDiv Proc Near Mov CL, 1 LDiv1: Xor SI, SI Mov DI, BP Or DI, DI JNZ LDiv2 Div BX XChg SI, DX Jmp LDiv6 LDiv2: Push CX Mov CX, 20 Mov DI, SI LDiv3: SHL AX, 1 RCL DX, 1 RCL SI, 1 RCL DI, 1 Cmp DI, BP JB LDiv5 JA LDiv4 Cmp SI, BX JB LDiv5 LDiv4: Sub SI, BX SBB DI, BP Inc AX LDiv5: Loop LDiv3 LDiv6: Test CL, 2 JZ LDiv7 XChg AX, SI Mov DX, DI LDiv7: Test CL, 4 JZ LDiv8 Neg DX Neg AX SBB DX, 0 LDiv8: Ret LongDiv EndP ;-----------------------------------------------------------------; ; Handle Program Terminations (Int 20h) ; ;-----------------------------------------------------------------; CloseRemaining Proc Near ; flush buffers; close any open files Call GetOldPID Call PutBlock Call WritePointerRec Call WriteTheCtrlRec Mov BX, 0 DoISR_4: Cmp FileHandleTbl [BX], 0FFFFh JE DoISR_6 Mov AX, OldPID Cmp AX, PIDTbl [BX] JNE DoISR_6 Push BX Mov BX, FileHandleTbl [BX] CallDOS CloseOP Dec FileCount Pop BX Mov FileHandleTbl [BX], 0FFFFh DoISR_6: Inc BX Inc BX Cmp BX, MaxHandles * 2 JB DoISR_4 DoISR_9: Mov DeCompHandle, 0FFFFh Mov CtrlHandle, 0FFFFh Mov PtrsHandle, 0FFFFh Ret CloseRemaining EndP ;-----------------------------------------------------------------; ; Handle Int 24 Critical Errors here ; ;-----------------------------------------------------------------; ISR24 Proc Far Mov CS:CritFlag, 1 Mov AL, 0 Cmp CS:DOSVersion, 3 JB ISR24Exit Mov AL, 3 ISR24Exit: IRet ISR24 EndP ;-----------------------------------------------------------------; ; Intercept Int20 (Terminate) call ; ;-----------------------------------------------------------------; ISR_20: STI Push DS Push ES Push CS ; addressability to this segment Pop DS Push DS Pop ES CLD Call CloseRemaining Pop ES Pop DS Mov AX, 4C00h ISR20Exit: Jmp CS:OldInt21 ;-----------------------------------------------------------------; ; Our stack (we don't want to trample someone else's!) ; ;-----------------------------------------------------------------; OurStack DB 256 dup("STACK ") EndStack DW 0 ;-----------------------------------------------------------------; ; The following location is the last resident byte ; ;-----------------------------------------------------------------; EndOfResident Label Byte ;-----------------------------------------------------------------; ; ; ; The following is non-resident code/data. It checks ; ; whether Diet Disk is already in memory, and either ; ; says "Already loaded!" or it installs the resident ; ; portion. ; ; ; ;-----------------------------------------------------------------; Start: Push CS Pop DS Call Installed JNC AlreadyThere Jmp NotPresent ; nope, it's okay to install AlreadyThere: Mov AH, WriteOp Mov BX, StdOut Mov DX, Offset Msg2 Mov CX, Msg2Siz Int 21h ; "We're already loaded!" message Mov AX, 4C00h ; exit, we're already loaded. Int 21h ; ; change vectors, etc. as necessary to install ourselves ; NotPresent: Mov AX, 5100h ;to get current PSP from DOS Int 21h ;PSP now in BX Mov OurPID,bx ;save our PSP Mov AH, 30h ; remember DOS version Int 21h Mov DOSVersion, AL Mov DOSVersMin, AH Mov OurSS, DS ; remember our ss/sp Mov AX, Offset EndStack Dec AX Dec AX Shl AX, 1 Shr AX, 1 Mov OurSP, AX Mov AH, GetDTAOp ; get DTA address Int 21h Mov OurDTAOfs, BX Mov OurDTASeg, ES Mov AX, 3521h ; Get address of int 21 Int 21h Mov Word Ptr OldInt21Ofs, BX Mov Word Ptr OldInt21Seg, ES Mov AX, 3520h ; Get address of int 20 Int 21h Mov Word Ptr OldInt20Ofs, BX Mov Word Ptr OldInt20Seg, ES Push DS Pop ES Mov AH, CurrentDiskOp ; generate <d>: Int 21h Add AL, "A" Mov AH, ":" Mov Word Ptr DietPath, AX Mov DietPath+2, '\' Mov SI, Offset DietPath Inc SI Inc SI Inc SI Mov DL, 0 Mov AH, GetCurrDir Int 21h Mov DI, Offset DietPath Mov CX, MaxName Mov AL, 0 RepNE ScaSB Dec DI Cmp Byte Ptr [DI-1], '\' JE DoDietName Mov Byte Ptr [DI], '\' Inc DI DoDietName: Mov SI, Offset DietDir Mov CX, LDietDir Rep MovSB Cmp DOSVersion, 3 JB CantShare Cmp DOSVersMin, 1 JB CantShare Mov BL, 3 TestNextDrive: Mov AX, 4409h Int 21h Test DX, 1000h JNZ YesNetwork Inc BL Cmp BL, 21 JB TestNextDrive Jmp Short CantShare YesNetwork: Mov RD_ONLY, 40h Mov RD_WR, 42h Mov DX, offset DietPath Mov AL, RD_ONLY Mov AH, OpenOp Int 21h JNC SaveDietHandle CantShare: Mov RD_ONLY, 00 Mov RD_WR, 02 OpenDietControl: Mov DX, offset DietPath Mov AL, RD_ONLY Mov AH, OpenOp Int 21h JNC SaveDietHandle Xor AX,AX ; doesn't exist SaveDietHandle: Mov DietDirHandle, AX Cmp AX, 0 JE NoDirFileMode Mov BX, DietDirHandle Mov AH, 3Eh Int 21h Cmp RD_ONLY, 0 JE StandaloneMode Mov CX, Msg3Siz Mov DX, Offset Msg3 Jmp Short StateTheMode NoDirFileMode: Mov CX, Msg5Siz Mov DX, Offset Msg5 Jmp Short StateTheMode StandaloneMode: Mov CX, Msg4Siz Mov DX, Offset Msg4 StateTheMode: Mov AH, WriteOp Mov BX, StdOut Int 21h Mov AH, WriteOp Mov BX, StdOut Mov DX, Offset Msg1 Mov CX, Msg1Siz Int 21h ; "We're loaded" message ; ; now terminate, but stay resident ; Mov DX, offset ISR_21 ; make it point to our routine Mov AX, 2521h Int 21h Mov DX, offset ISR_20 Mov AX, 2520h Int 21h Mov DX, offset EndOfResident Mov CX, 4h Shr DX, CL ; Turn byte addr. into paragraphs Add DX, 1 ; round up by 1 paragraph Mov AH, 31h Mov AL, 0 Int 21h ; terminate/stay resident ; - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Installed Proc Near Mov AX, 3341h Int 21h Cmp DX, 1234h JNE NotInst InstAlready: CLC Ret NotInst: STC Ret Installed EndP ;-----------------------------------------------------------------; ; ; ; Non-resident data area ; ; ; ;-----------------------------------------------------------------; Msg1 DB 13,10 DB "Diet Disk is loaded. (V 1.0)." DB 13,10 DB "Distributed from BIX: the BYTE Information Exchange" DB 13,10 Msg1Siz = $-Msg1 Msg2 DB 13,10 DB "Diet Disk is already running." DB 13,10 Msg2Siz = $-Msg2 Msg3 DB 13,10 DB "Diet Disk is in file-sharing mode." DB 13,10 Msg3Siz = $-Msg3 Msg4 DB 13,10 DB "Diet Disk is in non-file-sharing mode." DB 13,10 Msg4Siz = $-Msg4 Msg5 DB 13,10 DB "No DIET.DIR file was found." DB 13,10 Msg5Siz = $-Msg5 EndOfProgram = $ PSP EndS End Program