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📄 rxdossft.asm

📁 dos source
💻 ASM
📖 第 1 页 / 共 5 页
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        ;''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''';
        ;  Verify SFT/ JHT Available                                    ;
        ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -;
        ;                                                               ;
        ;  Returns:                                                     ;
        ;  ax   handle id #                                             ;
        ;...............................................................;

VerifyAvailableHandle:

        cmp word ptr ss:[ _RxDOS_CurrentPSP ], 0000
        jz verifyAvailHandles_26                        ; if no app -->

        push es
        push si
        push cx

        mov es, word ptr ss:[ _RxDOS_CurrentPSP ]       ; get PSP
        mov cx, word ptr es:[ pspFileHandleCount ]
        les si, dword ptr es:[ pspFileHandlePtr  ]

verifyAvailHandles_04:
        cmp byte ptr es:[ si ], -1                      ; empty slot ?
        jz verifyAvailHandles_08                        ; yes, allocate -->

        inc si                                          ; next
        loop verifyAvailHandles_04                      ; continue looping

        stc
        mov ax, offset pexterrNoHandlesAvailable        ; problem, no app handles left
        jmp short verifyAvailHandles_22                 ; exit -->

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  allocate App Handle
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

verifyAvailHandles_08:
        call FindAvailableSFTHandle                     ; locate avail System Handle
        jc verifyAvailHandles_22                        ; if none left -->
        dec word ptr es:[ sftRefCount ][ bx ]           ; release reservation count

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  return
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

verifyAvailHandles_22:
        pop cx
        pop si
        pop es

verifyAvailHandles_26:
        ret

        ;''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''';
        ;  Build Directory /SFT Entries                                 ;
        ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -;
        ;                                                               ;
        ;  Input:                                                       ;
        ;   es:di  pointer to diraccess                                 ;
        ;   cx     attributes                                           ;
        ;                                                               ;
        ;  Output:                                                      ;
        ;   ax     handle to an SFT                                     ;
        ;...............................................................;

createSFTEntry:

        Entry
        def  _drive
        def  _handle, -1                                ; SFT handle
        def  _DirEntryAttributes, cx                    ; directory attributes
        ddef _dirAccess, ss, di
        ddef _dirAddress                                ; address of empty loc found
        ddef _sftPointer                                ; sft pointer

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  find an available SFT
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        call FindAvailableSFTHandle                     ; find an available file handle
        ifc _createSFTEntry_42                          ; if none available -->

        mov word ptr [ _handle ][ bp ], ax              ; handle
        stordarg _sftPointer, es, bx                    ; sft pointer
        call InitSFTEntry                               ; clear entry

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  if file exists, delete file by releasing its clusters
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        mov si, word ptr [ _dirAccess. _pointer ][ bp ]

        mov ax, word ptr ss:[ fileAcDrive ][ si ]
        storarg _drive, ax                              ; save drive
        test ax, 8000h                                  ; does not exist flag ?
        jnz _createSFTEntry_20                          ; if no file -->

        mov si, word ptr [ _dirAccess. _pointer ][ bp ]
        les di, dword ptr ss:[ fileAcBufferPtr ][ si ]
        add di, word ptr ss:[ fileAcDirOffset ][ si ]   ; offset to entry in dir
        stordarg _dirAddress, es, di                    ; address of empty loc found

        mov dx, word ptr ss:[ fileAcCluster ][ si ]
        mov word ptr ss:[ fileAcCluster ][ si ], 0000
        call ReleaseClusterChain
        jmp short _createSFTEntry_24

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  if no file, locate empty slot and populate
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

_createSFTEntry_20:
        and ax, 7FFFh
        mov word ptr ss:[ fileAcDrive   ][ si ], ax
        mov dx, word ptr ss:[ fileAcDirCluster ][ si ]
        call LocateFreeDirSlot                          ; can we find a valid empty entry ?
        jc _createSFTEntry_40                           ; no -->

        stordarg _dirAddress, es, si                    ; address of empty loc found
        mov di, si                                      ; convert name to dir style

        mov si, word ptr [ _dirAccess. _pointer ][ bp ]
        mov si, word ptr ss:[ fileAcNameOffset ][ si ]
        call convFilenametoFCBString                    ; dir style name [si]-->[di]

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  update latest entry
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

_createSFTEntry_24:
        xor ax, ax
        mov cx, sizeDIRENTRY - sizeFILENAME             ; remainder of dir entry
        getdarg es, di, _dirAddress                     ; restore di pointer
        lea di, deAttributes [ di ]                     ; starting at attribs
        rep stosb                                       ; clear rest of entry

        mov si, word ptr [ _dirAddress. _pointer ][ bp ]
        mov cx, word ptr [ _DirEntryAttributes ][ bp ]  ; get attributes
        mov byte ptr es:[ deAttributes ][ si ], cl      ; attribute byte

        call getSysDateinDirFormat
        mov word ptr es:[ deTime ][ si ], ax            ; time created
        mov word ptr es:[ deDate ][ si ], dx            ; date created

        mov word ptr es:[ deStartCluster    ][ si ], 0000
        mov word ptr es:[ deFileSize. _low  ][ si ], 0000
        mov word ptr es:[ deFileSize. _high ][ si ], 0000

        call locateCCBPHeader                           ; get ccb header into es:di
        call CCBChanged                                 ; mark changes made
        call updateChangedCCB                           ; updated buffer to disk

        mov ax, offset errAccessDenied                  ; problem, access denied
        jc _createSFTEntry_40                           ; if error, release SFT -->

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  fix-up SFT
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        push word ptr [ _dirAddress. _segment ][ bp ]
        push word ptr [ _dirAddress. _pointer ][ bp ]   ; dir entry
        push word ptr [ _sftPointer. _segment ][ bp ]
        push word ptr [ _sftPointer. _pointer ][ bp ]   ; sft pointer
        call initSFTfromDirEntry

        getarg ax, _handle
        cmp word ptr es:[ sftDevInfo ][ di ], sftIsDevice
        clc
        jnz _createSFTEntry_42

        or word ptr es:[ sftDevInfo ][ di ], sftWritten ; is written when created
        jmp short _createSFTEntry_42

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  if error, release locked sft
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

_createSFTEntry_40:
        getdarg es, bx, _sftPointer                     ; get sft pointer
        dec word ptr es:[ sftRefCount ][ bx ]           ; release completely
        stc

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  return 
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

_createSFTEntry_42:
        Return

        ;''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''';
        ;  Build Directory /SFT Entries                                 ;
        ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -;
        ;                                                               ;
        ;  Input:                                                       ;
        ;   stack  pointer to directory entry                           ;
        ;   stack  sft pointer                                          ;
        ;                                                               ;
        ;  Output:                                                      ;
        ;   es:di  sft pointer                                          ;
        ;...............................................................;

initSFTfromDirEntry:

        Entry 4
        darg _dirAddress           
        darg _sftPointer                                ; sft pointer

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  init SFT
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        push ds
        xor ax, ax
        getdarg es, di, _sftPointer                     ; sft pointer
        add di, 2                                       ; skip Count entry
        mov cx, (sizeSFT - sftRefCount - 2)/ 2          ; effective count
        rep stosw                                       ; must have pointer at es: di

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  copy filename
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        getdarg ds, si, _dirAddress                     ; directory
        getdarg es, di, _sftPointer                     ; sft pointer
        lea di, offset sftFileName [ di ]               ; offset to filename
        mov cx, sizeFILENAME                            ; length of name/ ext
        rep movsb                                       ; copy name

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  populate sft
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        getdarg ds, si, _dirAddress                     ; directory
        getdarg es, di, _sftPointer                     ; sft pointer

        push word ptr [ deAttributes ][ si ]            ; attribute byte
        push word ptr [ deTime ][ si ]                  ; time last updated
        push word ptr [ deDate ][ si ]                  ; date last updated
        push word ptr [ deStartCluster ][ si ]          ; beginning cluster
        push word ptr [ deFilesize. _low  ][ si ]       ; file size
        push word ptr [ deFilesize. _high ][ si ]       ; file size

        pop word ptr es:[ sftFileSize. _high ][ di ]
        pop word ptr es:[ sftFileSize. _low  ][ di ]
        pop word ptr es:[ sftBegCluster ][ di ]
        pop word ptr es:[ sftDate ][ di ]
        pop word ptr es:[ sftTime ][ di ]
        pop ax
        mov byte ptr es:[ sftFileAttrib ][ di ], al

    ; set owner PSP

        mov ax, word ptr ss:[ _RxDOS_CurrentPSP ]       ; get owner PSP
        mov word ptr es:[ sftOwnerPSP ][ di ], ax

    ; set where in directory

        push es
        push di                                         ; pointer to sft
        setES ds                                        ; point dir buffer as [es][si]
        call locateCCBPHeader                           ; get ccb header into es:di
        mov si, di                                      ; ccb Header at [ds:si]

        pop di
        pop es                                          ; pointer to sft
        mov ax, word ptr [ ccbLBN. _low       ][ si ]
        mov dx, word ptr [ ccbLBN. _high      ][ si ]
        mov word ptr es:[ sftDirSector. _low  ][ di ], ax
        mov word ptr es:[ sftDirSector. _high ][ di ], dx

        mov cl, byte ptr [ ccbDrive ][ si ]             ; get drive
        and cx, sftDrivemask
        or word ptr es:[ sftDevInfo ][ di ], cx         ; include drive 

        mov ax, word ptr [ _dirAddress ][ bp ]
        sub ax, si                                      ; distance from start of ccb header
        sub ax, ccbData                                 ; distance from start of dir sector
        mov cl, sizeDIRENTRY                            ; bytes per entry
        div cl                                          ; remainder should be zero

        mov byte ptr es:[ sftDirIndex ][ di ], al

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
;  record disk drive volume id
;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        mov ax, word ptr es:[ sftDevInfo ][ di ]        ; drive 

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