518 lines
10 KiB
NASM
518 lines
10 KiB
NASM
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DOSSEG
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.MODEL LARGE
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include disk.inc
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.DATA?
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public DiskList
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DiskList dd ?
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.CODE
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ASSUME ds:NOTHING
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extrn InitializeInt13DiskList:far
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extrn OpenInt13Disk:far
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extrn CloseInt13Disk:far
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extrn Int13DiskIo:far
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extrn GetInt13DiskInfo:far
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.386
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;++
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;
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; UINT
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; _far
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; InitializeDiskList(
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; VOID
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; );
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;
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; Routine Description:
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;
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; This routine initializes internal data structures necessary so that
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; other disk-related routines in this module can be called.
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;
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; A data structure for each disk (currently int13 units only) is built
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; and saved away. The structure contains various info such as
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; drive geometry.
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;
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; This routine may be called multiple times. Subsequent calls after
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; the first simply return the disk count.
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;
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; Arguments:
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;
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; None.
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;
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; Return Value:
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;
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; Total count of all hard drives that we can deal with.
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; 0 if an error occurs.
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;
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;--
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public _InitializeDiskList
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_InitializeDiskList proc far
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push ds
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push si
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;
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; See if we're initialized yet by counting items in the DiskList
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; linked list. If 0, then assume not initialized yet.
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;
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mov ax,DGROUP
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mov ds,ax
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mov si,OFFSET DGROUP:DiskList
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mov ax,0
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idl1:
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.errnz DiskInfoNextl
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mov cx,[si].DiskInfoNextl
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or cx,[si].DiskInfoNexth
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jz idl2
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inc ax
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lds si,[si].DiskInfoNext
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jmp short idl1
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idl2:
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cmp ax,0
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jne idl3
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;
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; Currently we deal with int13 disks only.
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;
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push ax ; disk ids start at 0
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call InitializeInt13DiskList
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add sp,2
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idl3:
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pop si
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pop ds
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retf
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_InitializeDiskList endp
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;++
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;
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; HDISK
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; _far
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; OpenDisk(
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; IN UINT DiskId
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; );
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;
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; Routine Description:
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;
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; This routine "opens" a disk so that i/o can be performed to it.
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; Housekeeping such as locking, etc, is performed.
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; A disk can be opened only once at a time.
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;
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; Arguments:
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;
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; DiskId - supplies an ordinal value for the disk to be opened.
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; Range is 0 - n-1, where n is the value returned by
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; InitializeDiskList().
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;
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; Return Value:
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;
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; Handle, or 0 if an error occurs.
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;
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;--
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DiskId equ word ptr [bp+6]
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public _OpenDisk
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_OpenDisk proc far
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push bp
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mov bp,sp
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push ds
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push si
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;
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; Locate the disk record corresponding to this disk id.
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;
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mov ax,DiskId
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call far ptr pLocateDiskRecord
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mov cx,si
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or cx,dx
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mov ax,0
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jz od_done ; dx:ax already 0 for error return
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od_gotrec:
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;
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; Make sure disk is not already open
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;
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cmp [si].DiskInfoDiskOpen,al
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jz @f
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mov dx,ax ; dx:ax = 0
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jnz od_done ; disk already open, error.
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@@:
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;
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; Int13 disks only for now.
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;
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push ds
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push si
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call OpenInt13Disk
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pop si
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pop ds
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cmp ax,0
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jnz @f
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mov dx,ax
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jz od_done ; error, dx:ax set for return
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@@: inc [si].DiskInfoDiskOpen
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mov dx,ds
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mov ax,si ; dx:ax = handle for return
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od_done:
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pop si
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pop ds
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leave
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retf
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_OpenDisk endp
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;++
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;
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; VOID
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; _far
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; CloseDisk(
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; IN HDISK DiskHandle
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; );
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;
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; Routine Description:
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;
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; This routine "closes" a disk previously opened by OpenDisk().
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; Housekeeping such as unlocking, etc, is performed.
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;
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; Arguments:
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;
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; DiskHandle - supplies the handle of the disk to be closed,
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; as previously opened by OpenDisk().
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;
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; Return Value:
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;
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; None.
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;
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;--
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DiskHandle equ dword ptr [bp+6]
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public _CloseDisk
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_CloseDisk proc far
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push bp
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mov bp,sp
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push ds
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push si
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lds si,DiskHandle
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cmp [si].DiskInfoDiskOpen,0
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jz cd_done ; not open, nothing to do
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;
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; Int13 disks only for now
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;
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push ds
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push si
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call CloseInt13Disk
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pop si
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pop ds ; ds:si -> disk record
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dec [si].DiskInfoDiskOpen
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cd_done:
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pop si
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pop ds
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leave
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retf
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_CloseDisk endp
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;++
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;
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; BOOL
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; _far
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; GetDiskInfoByHandle(
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; IN HDISK DiskHandle,
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; OUT FPBYTE Int13UnitNumber,
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; OUT FPBYTE SectorsPerTrack,
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; OUT FPUSHORT Heads,
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; OUT FPUSHORT Cylinders,
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; OUT FPULONG ExtendedSectorCount,
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; OUT FPUINT DiskId
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; );
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;
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; BOOL
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; _far
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; GetDiskInfoById(
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; IN UINT DiskId,
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; IN UINT Reserved,
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; OUT FPBYTE Int13UnitNumber,
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; OUT FPBYTE SectorsPerTrack,
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; OUT FPUSHORT Heads,
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; OUT FPUSHORT Cylinders,
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; OUT FPULONG ExtendedSectorCount
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; );
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;
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; Routine Description:
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;
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; These routines fetch information about a disk.
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;
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; Arguments:
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;
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; Return Value:
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;
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; non-0 - success
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; 0 - failure
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;
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;--
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DiskHandle equ dword ptr [bp+6]
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DiskId equ word ptr [bp+6]
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Int13UnitNumber equ dword ptr [bp+10]
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SectorsPerTrack equ dword ptr [bp+14]
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Heads equ dword ptr [bp+18]
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Cylinders equ dword ptr [bp+22]
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ExtendedSecCnt equ dword ptr [bp+26]
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pDiskId equ dword ptr [bp+30]
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public _GetDiskInfoById
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_GetDiskInfoById proc far
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push bp
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mov bp,sp
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push ds
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push si
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;
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; Locate the disk record.
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;
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mov ax,DiskId
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call far ptr pLocateDiskRecord
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cmp dx,0
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jnz gdi_do_it
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cmp si,0
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jnz gdi_do_it
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mov ax,dx
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jz gdi_done
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gdi_do_it:
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;
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; Int13 disks are the only ones supported now so we can
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; just call the int13-specific disk info routine.
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;
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push ExtendedSecCnt
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push Cylinders
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push Heads
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push SectorsPerTrack
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push Int13UnitNumber
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push ds
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push si
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call GetInt13DiskInfo
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add sp,24
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mov ax,1
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gdi_done:
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pop si
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pop ds
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leave
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retf
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_GetDiskInfoById endp
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public _GetDiskInfoByHandle
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_GetDiskInfoByHandle proc far
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push bp
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mov bp,sp
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push ds
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push si
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;
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; Make sure the disk is open.
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;
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lds si,DiskHandle
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cmp [si].DiskInfoDiskOpen,0
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jz @f
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;
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; Set disk id in caller's variable
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;
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mov ax,[si].DiskInfoDiskId
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lds si,pDiskId
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mov [si],ax
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lds si,DiskHandle
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jmp short gdi_do_it
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@@: mov ax,0
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jz gdi_done
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_GetDiskInfoByHandle endp
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;++
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;
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; BOOL
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; _far
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; ReadDisk(
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; IN HDISK DiskHandle,
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; IN ULONG StartSector,
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; IN BYTE SectorCount,
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; OUT PVOID Buffer
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; );
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;
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; BOOL
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; _far
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; WriteDisk(
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; IN HDISK DiskHandle,
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; IN ULONG StartSector,
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; IN BYTE SectorCount,
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; IN PVOID Buffer
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; );
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;
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; Routine Description:
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;
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; These routines perform i/o to a disk previously opened with
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; OpenDisk().
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;
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; Arguments:
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;
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; DiskHandle - supplies the handle of the disk to be read/written,
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; as previously opened by OpenDisk().
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;
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; StartSector - supplies the physical start sector where the read/write
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; is to begin.
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;
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; SectorCount - supplies the number of sectors to be read/written.
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;
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; Buffer - supplies a buffer for the transfer.
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;
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; Return Value:
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;
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; non-0 - success
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; 0 - failure
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;
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;--
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DiskHandle equ dword ptr [bp+6]
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StartSector equ dword ptr [bp+10]
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SectorCount equ word ptr [bp+14]
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Buffer equ dword ptr [bp+16]
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public _WriteDisk
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_WriteDisk label far
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mov ax,1
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jmp short DiskIo
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public _ReadDisk
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_ReadDisk label far
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mov ax,0
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DiskIo proc far
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push bp
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mov bp,sp
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push ds
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push si
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lds si,DiskHandle
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cmp [si].DiskInfoDiskOpen,0
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jnz @f
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mov ax,0 ; not open, error out
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jz rd_done
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;
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; Int13 disks only for now
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;
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@@: push ax
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push Buffer
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push SectorCount
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push StartSector ; only care about low byte
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push ds
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push si
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call Int13DiskIo
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add sp,16
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rd_done:
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pop si
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pop ds
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leave
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retf
|
||
|
|
|
||
|
|
DiskIo endp
|
||
|
|
|
||
|
|
|
||
|
|
;++
|
||
|
|
;
|
||
|
|
; PVOID
|
||
|
|
; _far
|
||
|
|
; pLocateDiskRecord(
|
||
|
|
; IN UINT DiskId
|
||
|
|
; );
|
||
|
|
;
|
||
|
|
; Routine Description:
|
||
|
|
;
|
||
|
|
; Internal routine.
|
||
|
|
;
|
||
|
|
; This routine locates a disk record in the linked list
|
||
|
|
; of all disk records as prepared by InitializeDiskList().
|
||
|
|
;
|
||
|
|
; Arguments:
|
||
|
|
;
|
||
|
|
; DiskId - supplies an ordinal value identifying the disk.
|
||
|
|
; Valid range is 0 - n-1, where n is the number returned
|
||
|
|
; from InitializeDiskList().
|
||
|
|
;
|
||
|
|
; This parameter is passed in ax, not on the stack.
|
||
|
|
;
|
||
|
|
; Return Value:
|
||
|
|
;
|
||
|
|
; NULL if record not located.
|
||
|
|
; Otherwise fills ds:si and dx:si with a far pointer to the
|
||
|
|
; disk record.
|
||
|
|
;
|
||
|
|
;--
|
||
|
|
pLocateDiskRecord proc far
|
||
|
|
|
||
|
|
mov dx,DGROUP
|
||
|
|
mov ds,dx
|
||
|
|
mov si,offset DGROUP:[DiskList] ; ds:si = &DiskList
|
||
|
|
|
||
|
|
;
|
||
|
|
; Note that this code depends on the link field in the
|
||
|
|
; disk record structure being first!
|
||
|
|
;
|
||
|
|
.errnz DiskInfoNext
|
||
|
|
ldr_loop:
|
||
|
|
lds si,[si].DiskInfoNext
|
||
|
|
mov dx,ds
|
||
|
|
cmp dx,0
|
||
|
|
jz ldr_done ; end of list, we're done
|
||
|
|
cmp [si].DiskInfoDiskId,ax
|
||
|
|
jz ldr_done
|
||
|
|
jmp short ldr_loop
|
||
|
|
|
||
|
|
ldr_done:
|
||
|
|
retf
|
||
|
|
|
||
|
|
pLocateDiskRecord endp
|
||
|
|
|
||
|
|
end
|