
    <<FloppyImplInterface.mesa>>
        <<Copyright Ó 1983, 1985, 1987  by Xerox Corporation. All rights reserved. >>
        <<Tim Diebert: May 7, 1987 12:53:04 pm PDT>>

    DIRECTORY
        Floppy USING [BootFilePointer, Density, FileID, nullFileID, PageCount, PageNumber, Sides, VolumeHandle],
        FloppyChannel USING [Context, DiskAddress, Handle, SectorCount],
        FloppyFormat USING [BadSpotSectors, FileList, ImplementedFileSize, Sector, SectorNine],
        PrincOps USING [bitsPerWord, PageCount, wordsPerPage],
        VM USING [Interval];

    FloppyImplInterface: DEFINITIONS = BEGIN

        <<Private TYPE's, constants and variables>>

        Bug: ERROR [type: BugType];
        BugType: TYPE = {
            trackBufferLengthTooSmall, wrappedAroundFileIDs, invalidAddress, invalidBufferSize,
            floppyVolumeTooLarge};

        IOError: ERROR[countDone: CARDINAL];
        DiskChanged: ERROR;

        volumeTable: LONG POINTER TO ARRAY [0..0) OF VolumeDesc; -- indexed by device indexes.
        VolumeDesc: TYPE = LONG POINTER TO VolumeDescObject;
        VolumeDescObject: TYPE = MONITORED RECORD [
            open: BOOLEAN,
            changeCount: CARDINAL, -- change count at last open
            writeProtected: BOOLEAN, -- either physically or logically write protected
            density: Floppy.Density[single..double],
            sides: Floppy.Sides[one..two], 
            handle: FloppyChannel.Handle, -- handle on this particular instance of the floppy
            numPages: Floppy.PageCount, -- count of the total number of pages on the volume
            fileList: LONG POINTER TO FloppyFormat.FileList,
            fileListSpace: VM.Interval, -- only allocated when the volume is open
            sectorNine: LONG POINTER TO FloppyFormat.SectorNine,
            badPageMap: LONG POINTER TO FloppyFormat.BadSpotSectors,
            trackZeroSpace: VM.Interval,
            allocationMap: LONG POINTER TO PACKED ARRAY [0..0) OF Allocation,
            allocationMapSpace: VM.Interval -- only allocated when the volume is open
            ];

        Allocation: TYPE =  MACHINE DEPENDENT {allocated (0), free (1), markerPage (2), badPage (3)};
            <<If add more, change the next line!>>
        allocationsPerPage: CARDINAL = (PrincOps.wordsPerPage*PrincOps.bitsPerWord)/2;

        FileListType: -- File.Type -- CARDINAL = 0 -- CommonSoftwareFileTypes.tFileList -- ;


        AccessFloppy: PROCEDURE [volumeDesc: VolumeDesc, buffer: LONG POINTER,
        address: FloppyChannel.DiskAddress, count: CARDINAL, access: AccessMode];

        AccessMode: TYPE = {read, write};

        AddFile: PROCEDURE [volumeDesc: VolumeDesc, file: Floppy.FileID,
        size: FloppyFormat.ImplementedFileSize, type: -- File.Type -- CARDINAL,
        location: FloppyFormat.Sector];

        AllocateFile: PROCEDURE [volumeDesc: VolumeDesc, bigSize: Floppy.PageCount,
        type: -- File.Type -- CARDINAL, startPage: FloppyFormat.Sector,
        id: Floppy.FileID _ Floppy.nullFileID]
        RETURNS [startingSector: FloppyFormat.Sector, file: Floppy.FileID];

        CloseVolume: PROCEDURE [volumeDesc: VolumeDesc];

        CreateBuffer: PROCEDURE [size: PrincOps.PageCount] RETURNS [buffer: VM.Interval];

        CreateFileInternal: PROCEDURE [volumeDesc: VolumeDesc, size: Floppy.PageCount,
            type: -- File.Type -- CARDINAL, startSector: FloppyFormat.Sector,
            id: Floppy.FileID _ Floppy.nullFileID]
            RETURNS[fileID: Floppy.FileID, startPage: FloppyFormat.Sector];

        CreateInitialMicrocodeInternal: PROCEDURE [
            volumeDesc: VolumeDesc, size: Floppy.PageCount, type: -- File.Type -- CARDINAL,
            startingPageNumber: Floppy.PageNumber, id: Floppy.FileID _ Floppy.nullFileID]
            RETURNS[file: Floppy.FileID];

        FindFile: PROCEDURE [volumeDesc: VolumeDesc, file: Floppy.FileID]
        RETURNS [address: FloppyFormat.Sector, type: -- File.Type -- CARDINAL,
        size: FloppyFormat.ImplementedFileSize];

        FirstDataSector: PROCEDURE [volumeDesc: VolumeDesc] RETURNS [FloppyFormat.Sector];

        GetBootFileAddress: PROCEDURE [volumeDesc: VolumeDesc, bootFile: Floppy.BootFilePointer]
        RETURNS [address: FloppyFormat.Sector];

        GetFileID: PROCEDURE [volumeDesc: VolumeDesc] RETURNS [fileID: Floppy.FileID];

        InitializeAllocationMap: PROCEDURE [volumeDesc: VolumeDesc];

        IsDriveWriteProtected: PROCEDURE [volumeDesc: VolumeDesc]
        RETURNS [writeProtected: BOOLEAN];

        ReadFloppy: PROCEDURE [volumeDesc: VolumeDesc, buffer: LONG POINTER,
        address: FloppyFormat.Sector, count: FloppyFormat.ImplementedFileSize];

        RemoveFile: PROCEDURE [volumeDesc: VolumeDesc, file: Floppy.FileID];

        SectorsPerTrack: PROCEDURE [handle: FloppyChannel.Handle,
        context: FloppyChannel.Context] RETURNS [sectorsPerTrack: FloppyChannel.SectorCount];

        SetBlock: PROCEDURE [p: LONG POINTER, length: CARDINAL, value: CARDINAL];

        ValidateHandle: PROCEDURE[volume: Floppy.VolumeHandle]
        RETURNS[volumeDesc: VolumeDesc];

        ValidDrive: PROCEDURE [drive: CARDINAL] RETURNS [exists: BOOLEAN];

        VolumeChanging: PROCEDURE [volumeDesc: VolumeDesc];

        VolumeStable: PROCEDURE [volumeDesc: VolumeDesc];

        WordsToPages: PROCEDURE [count: LONG CARDINAL] RETURNS [CARDINAL] = INLINE
            {RETURN [CARDINAL[(count+PrincOps.wordsPerPage-1)/PrincOps.wordsPerPage]]};

        WriteFileList: PROCEDURE [volumeDesc: VolumeDesc];

        WriteFloppy: PROCEDURE [volumeDesc: VolumeDesc, buffer: LONG POINTER,
        address: FloppyFormat.Sector, count: FloppyFormat.ImplementedFileSize];

        WriteSectorNine: PROCEDURE [volumeDesc: VolumeDesc]; 

        END.