941 lines
23 KiB
NASM
941 lines
23 KiB
NASM
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DOSSEG
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.MODEL LARGE
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include disk.inc
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;
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; Disk record structure specific to int13-visible disks.
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;
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INT13_DISK_INFO STRUC
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;
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; First part is a DiskInfo structure
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;
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DiskInfo db SIZE DISK_INFO DUP (?)
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;
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; Int13 unit number and drive geometry for drive.
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;
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Int13DiskUnit db ?
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Int13SectorsPerTrack db ?
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Int13Heads dw ?
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Int13Cylinders dw ?
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Int13xSectorCountl dw ?
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Int13xSectorCounth dw ?
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INT13_DISK_INFO ENDS
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.DATA?
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extrn DiskList:dword
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;
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; Table of drives for which xint13 is disabled
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; 128 units at 1 bit each = 128 bits = 16 bytes = 8 words
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;
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; We support this solely by returning a zero
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; extended sector count from pGetExtendedInt13SectorCount;
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; this forces everyone else into regular int13 mode.
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;
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xInt13DisableTable db 16 dup (?)
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.CODE
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ASSUME ds:NOTHING
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extrn _malloc: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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; InitializeInt13DiskList(
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; IN UINT FirstDiskId
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; );
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;
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; Routine Description:
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;
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; This routine determines the number of int13 disk units and
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; gathers information about each, which is saved in a structure.
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; The structures are stored in a linked list whose head is
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; the DiskList global variable.
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;
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; Arguments:
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;
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; FirstDiskId - supplies the id to be used for the first disk.
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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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FirstDiskId equ word ptr [bp+6]
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public InitializeInt13DiskList
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InitializeInt13DiskList 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 es
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push bx
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push si
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push di
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mov ah,8
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mov dl,80h
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int 13h
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jnc @f
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xor dl,dl
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@@: or dl,80h
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xor dh,dh
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mov di,dx ; di = int13 disk limit
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mov si,80h ; si = current int13 disk
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nextdisk:
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cmp si,di
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je ildoneok ; no more disks
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push ds
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push DGROUP
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pop ds ; crt needs ds to address _DATA
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push SIZE INT13_DISK_INFO
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call _malloc
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add sp,2
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pop ds
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mov cx,ax
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or cx,dx
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jz ildone ; ax already 0 for error return
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push ax
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push dx ; save disk record pointer
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push si ; save current int13 unit #
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push di ; save int13 unit # limit
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mov dx,si ; dl = int13 unit #
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mov ah,8
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int 13h
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pop di ; di = int13 disk limit
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pop bx ; bl = int13 unit #, bh = 0
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pop ds
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pop si ; ds:si -> new disk record
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jnc @f
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mov ax,0
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jmp short ildone
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;
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; Store int13 unit number in disk record.
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; Also generate a disk id.
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;
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@@: mov ax,bx
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sub ax,80h
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add ax,FirstDiskId
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mov [si].DiskInfo.DiskInfoDiskId,ax
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mov [si].DiskInfo.DiskInfoDiskOpen,bh ; bh=0, set disk not open
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mov [si].Int13DiskUnit,bl
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;
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; Max head is in in dh, convert to count in dx
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;
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shr dx,8
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inc dx
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mov [si].Int13Heads,dx
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;
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; Deal with sectors per track in cl
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;
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mov al,cl
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and al,3fh
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mov [si].Int13SectorsPerTrack,al
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;
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; Deal with cylinder count wierdness
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;
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xchg ch,cl
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shr ch,6
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inc cx
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mov [si].Int13Cylinders,cx
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;
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; Fetch extended int13 count. Comes back as 0 if xint13
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; not supported for the drive.
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;
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push bx
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call far ptr pGetExtendedInt13SectorCount
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pop cx ; cl = int13 unit#, ch = 0
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mov [si].Int13xSectorCountl,ax
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mov [si].Int13xSectorCounth,dx
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;
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; Now link the disk record into the linked list.
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;
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mov dx,di ; dx = int13 unit # limit
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mov ax,DGROUP
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mov es,ax
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mov di,OFFSET DGROUP:DiskList ; es:di = &DiskList
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mov ax,es:[di]
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mov [si].DiskInfo.DiskInfoNextl,ax
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mov ax,es:[di+2]
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mov [si].DiskInfo.DiskInfoNexth,ax
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mov es:[di],si
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mov ax,ds
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mov es:[di+2],ax
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mov di,dx ; di = int13 unit # limit
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mov si,cx ; si = int13 unit #
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inc si
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jmp nextdisk
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ildoneok:
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mov ax,si
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sub ax,80h ; ax = int13 disk count
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ildone:
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pop di
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pop si
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pop bx
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pop es
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pop ds
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leave
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retf
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InitializeInt13DiskList endp
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;++
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;
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; BOOL
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; _far
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; OpenInt13Disk(
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; IN FPINT13_DISK_INFO DiskRecord
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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" an int13 disk.
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; Housekeeping such as locking, etc, is performed.
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;
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; It is assumed that a disk can be opened only once at a time,
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; but the caller is responsible for enforcing this.
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;
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; Arguments:
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;
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; DiskRecord - supplies a far pointer to the disk record struct
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; for the disk to be opened.
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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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DiskRecord equ dword ptr [bp+6]
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public OpenInt13Disk
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OpenInt13Disk proc far
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;
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; BUGBUG perform locking for OSR2
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;
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mov ax,1
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retf
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OpenInt13Disk endp
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;++
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;
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; VOID
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; _far
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; CloseInt13Disk(
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; IN FPINT13_DISK_INFO DiskRecord
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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" an int13 disk previously opened with
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; OpenInt13Disk. Housekeeping such as locking, etc, is performed.
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;
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; Arguments:
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;
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; DiskRecord - supplies a far pointer to the disk record struct
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; for the disk to be closed.
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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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DiskRecord equ dword ptr [bp+6]
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public CloseInt13Disk
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CloseInt13Disk proc far
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;
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; BUGBUG perform unlocking for OSR2
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;
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retf
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CloseInt13Disk endp
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;
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; BOOL
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; _far
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; pInt13Read(
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; IN FPINT13_DISK_INFO DiskRecord,
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; IN ULONG StartSector,
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; IN BYTE SectorCount,
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; OUT FPVOID Buffer
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; );
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;
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; BOOL
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; _far
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; pInt13Read(
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; IN FPINT13_DISK_INFO DiskRecord,
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; IN ULONG StartSector,
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; IN BYTE SectorCount,
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; IN FPVOID Buffer
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; );
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;
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DiskRecord equ dword ptr [bp+6]
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StartSectorl equ word ptr [bp+10]
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StartSectorh equ word ptr [bp+12]
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SectorCount equ byte ptr [bp+14]
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Buffer equ dword ptr [bp+16]
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public pInt13Read
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pInt13Read label far
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mov ah,2
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jmp short pInt13IO
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public pInt13Write
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pInt13Write label far
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mov ah,3
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pInt13IO 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 es
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push bx
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push si
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push di
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push ax
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lds si,DiskRecord
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;
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; Calculate sectors per cylinder, which is a max of 63*256 = 16128,
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; which fits in a word register. But we do a full 32-bit multiply,
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; because the heads count could be 256 (which doesn't fit in al).
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;
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mov al,[si].Int13SectorsPerTrack
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cbw ; ax = sectors per track
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mul [si].Int13Heads ; ax = sectors per cylinder
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mov bx,ax ; bx = sectors per cylinder
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mov dx,StartSectorh
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mov ax,StartSectorl ; dx:ax = start sector
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||
|
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div bx ; ax = cyl, dx = sector in cyl
|
||
|
|
|
||
|
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;
|
||
|
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; Set up the cylinder in cx in int13 format:
|
||
|
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;
|
||
|
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; ch = bits 0-7 of the cylinder
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||
|
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; bits 6,7 of cl = bits 8,9 of the cylinder
|
||
|
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;
|
||
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mov cx,ax
|
||
|
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xchg cl,ch
|
||
|
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shl cl,6
|
||
|
|
|
||
|
|
;
|
||
|
|
; Now calculate the head and sector. The head is max 255
|
||
|
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; and the sector is max 62, meaning we can do a 16-bit divide.
|
||
|
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;
|
||
|
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mov ax,dx ; ax = sector within cylinder
|
||
|
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div [si].Int13SectorsPerTrack ; al = head, ah = sector
|
||
|
|
|
||
|
|
;
|
||
|
|
; Pack everything into int13 format.
|
||
|
|
;
|
||
|
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inc ah ; sector is 1-based (1-63)
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||
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or cl,ah
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mov dh,al ; dh = head
|
||
|
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|
||
|
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mov dl,[si].Int13DiskUnit
|
||
|
|
|
||
|
|
les bx,Buffer
|
||
|
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pop ax ; ah = operation (2 or 3)
|
||
|
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mov al,SectorCount
|
||
|
|
|
||
|
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int 13h
|
||
|
|
|
||
|
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setnc al
|
||
|
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cbw
|
||
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|
||
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pop di
|
||
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pop si
|
||
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pop bx
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||
|
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pop es
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||
|
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pop ds
|
||
|
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|
||
|
|
leave
|
||
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|
retf
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||
|
|
|
||
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pInt13IO endp
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||
|
|
|
||
|
|
|
||
|
|
;
|
||
|
|
; BOOL
|
||
|
|
; _far
|
||
|
|
; pXInt13Read(
|
||
|
|
; IN FPINT13_DISK_INFO DiskRecord,
|
||
|
|
; IN ULONG StartSector,
|
||
|
|
; IN BYTE SectorCount,
|
||
|
|
; OUT FPVOID Buffer
|
||
|
|
; );
|
||
|
|
;
|
||
|
|
; BOOL
|
||
|
|
; _far
|
||
|
|
; pXInt13Read(
|
||
|
|
; IN FPINT13_DISK_INFO DiskRecord,
|
||
|
|
; IN ULONG StartSector,
|
||
|
|
; IN BYTE SectorCount,
|
||
|
|
; IN FPVOID Buffer
|
||
|
|
; );
|
||
|
|
;
|
||
|
|
|
||
|
|
DiskRecord equ dword ptr [bp+6]
|
||
|
|
StartSector equ dword ptr [bp+10]
|
||
|
|
SectorCount equ byte ptr [bp+14]
|
||
|
|
Buffer equ dword ptr [bp+16]
|
||
|
|
|
||
|
|
public pXInt13Read
|
||
|
|
pXInt13Read label far
|
||
|
|
|
||
|
|
mov ah,42h
|
||
|
|
jmp short pXInt13IO
|
||
|
|
|
||
|
|
public pXInt13Write
|
||
|
|
pXInt13Write label far
|
||
|
|
|
||
|
|
mov ax,4300h ; need to clear bit 0 (verify flag)
|
||
|
|
|
||
|
|
pXInt13IO proc far
|
||
|
|
|
||
|
|
push bp
|
||
|
|
mov bp,sp
|
||
|
|
|
||
|
|
push ds
|
||
|
|
push es
|
||
|
|
push bx
|
||
|
|
push si
|
||
|
|
push di
|
||
|
|
|
||
|
|
lds si,DiskRecord ; ds:si -> disk record
|
||
|
|
mov dl,[si].Int13DiskUnit
|
||
|
|
|
||
|
|
push 0 ; high dword of sector # is 0
|
||
|
|
push 0
|
||
|
|
push StartSector
|
||
|
|
push Buffer
|
||
|
|
mov bl,SectorCount ; sector count
|
||
|
|
xor bh,bh ; make sure high byte is 0
|
||
|
|
push bx
|
||
|
|
push 16 ; packet size
|
||
|
|
|
||
|
|
push ss
|
||
|
|
pop ds
|
||
|
|
mov si,sp ; ds:si -> param packet on stack
|
||
|
|
|
||
|
|
int 13h ; ax already set up from above
|
||
|
|
|
||
|
|
setnc al
|
||
|
|
cbw ; ax: 0=failure, 1=success
|
||
|
|
add sp,16 ; get rid of param packet on stack
|
||
|
|
|
||
|
|
pop di
|
||
|
|
pop si
|
||
|
|
pop bx
|
||
|
|
pop es
|
||
|
|
pop ds
|
||
|
|
|
||
|
|
leave
|
||
|
|
retf
|
||
|
|
|
||
|
|
pXInt13IO endp
|
||
|
|
|
||
|
|
|
||
|
|
;++
|
||
|
|
;
|
||
|
|
; BOOL
|
||
|
|
; _far
|
||
|
|
; Int13DiskIo(
|
||
|
|
; IN FPINT13_DISK_INFO DiskRecord
|
||
|
|
; IN ULONG StartSector,
|
||
|
|
; IN BYTE SectorCount,
|
||
|
|
; IN OUT FPVOID Buffer,
|
||
|
|
; IN BOOL Write
|
||
|
|
; );
|
||
|
|
;
|
||
|
|
; Routine Description:
|
||
|
|
;
|
||
|
|
; This routine performs disk i/o using int13 services, automatically
|
||
|
|
; using extended int13 services if available for the drive.
|
||
|
|
;
|
||
|
|
; This routine DOES ensure that i/o will not cross a track boundary
|
||
|
|
; to ensure maximum compatibility with various BIOSes out there.
|
||
|
|
;
|
||
|
|
; Arguments:
|
||
|
|
;
|
||
|
|
; DiskRecord - supplies pointer to the disk record structure for the
|
||
|
|
; disk to be read from or written to.
|
||
|
|
;
|
||
|
|
; StartSector - supplies the physical start sector where the transfer
|
||
|
|
; is to start.
|
||
|
|
;
|
||
|
|
; SectorCount - supplies the number of sectors to be transfered.
|
||
|
|
;
|
||
|
|
; Buffer - supplies the target buffer for reads or the data for write.
|
||
|
|
;
|
||
|
|
; Write - non-0 means write operation, 0 means read operation.
|
||
|
|
;
|
||
|
|
; Return Value:
|
||
|
|
;
|
||
|
|
; non-0 - success
|
||
|
|
; 0 - failure
|
||
|
|
;
|
||
|
|
;--
|
||
|
|
|
||
|
|
DiskRecord equ dword ptr [bp+6]
|
||
|
|
StartSector equ dword ptr [bp+10]
|
||
|
|
StartSectorl equ word ptr [bp+10]
|
||
|
|
StartSectorh equ word ptr [bp+12]
|
||
|
|
SectorCount equ byte ptr [bp+14]
|
||
|
|
Buffer equ dword ptr [bp+16]
|
||
|
|
Bufferl equ word ptr [bp+18]
|
||
|
|
Bufferh equ word ptr [bp+18]
|
||
|
|
Write equ word ptr [bp+20]
|
||
|
|
|
||
|
|
IoRoutine equ dword ptr [bp-4]
|
||
|
|
IoRoutinel equ word ptr [bp-4]
|
||
|
|
IoRoutineh equ word ptr [bp-2]
|
||
|
|
|
||
|
|
public Int13DiskIo
|
||
|
|
Int13DiskIo proc far
|
||
|
|
|
||
|
|
push bp
|
||
|
|
mov bp,sp
|
||
|
|
sub sp,4
|
||
|
|
|
||
|
|
push ds
|
||
|
|
push es
|
||
|
|
push bx
|
||
|
|
push si
|
||
|
|
push di
|
||
|
|
|
||
|
|
;
|
||
|
|
; Address the disk record structure to determine
|
||
|
|
; which set of int13 services to use (standard or extended).
|
||
|
|
; We'll use extended if they are supported for the drive.
|
||
|
|
; Even in that case, however, we'll do i/o a track at a time
|
||
|
|
; to ensure maximum compatibility.
|
||
|
|
;
|
||
|
|
lds si,DiskRecord
|
||
|
|
mov ax,Write
|
||
|
|
cmp [si].Int13xSectorCountl,0
|
||
|
|
jnz io_xint13
|
||
|
|
cmp [si].Int13xSectorCounth,0
|
||
|
|
jnz io_xint13
|
||
|
|
|
||
|
|
cmp ax,1
|
||
|
|
je @f
|
||
|
|
mov dx,SEG pInt13Read
|
||
|
|
mov ax,OFFSET pInt13Read
|
||
|
|
jmp short store_io
|
||
|
|
@@: mov dx,SEG pInt13Write
|
||
|
|
mov ax,OFFSET pInt13Write
|
||
|
|
jmp short store_io
|
||
|
|
io_xint13:
|
||
|
|
cmp ax,1
|
||
|
|
je @f
|
||
|
|
mov dx,SEG pXInt13Read
|
||
|
|
mov ax,OFFSET pXInt13Read
|
||
|
|
jmp short store_io
|
||
|
|
@@: mov dx,SEG pXInt13Write
|
||
|
|
mov ax,OFFSET pXInt13Write
|
||
|
|
store_io:
|
||
|
|
mov IoRoutinel,ax
|
||
|
|
mov IoRoutineh,dx
|
||
|
|
|
||
|
|
;
|
||
|
|
; Figure out how many sectors are left in the first track.
|
||
|
|
; Note that this calculation can overflow, since the sector
|
||
|
|
; can be very large (like in the xint13 case) and thus the
|
||
|
|
; absolute track number can easily be > 64k. To get around this
|
||
|
|
; we calculate the cylinder and remainder first, and then
|
||
|
|
; degenerate the remainder into track and sector.
|
||
|
|
;
|
||
|
|
; Max sectors per cylinder = 63*256, which fits in a word register.
|
||
|
|
;
|
||
|
|
mov al,[si].Int13SectorsPerTrack
|
||
|
|
cbw
|
||
|
|
mul [si].Int13Heads ; ax = sectors per cylinder
|
||
|
|
mov cx,ax ; cx = sectors per cylinder
|
||
|
|
mov dx,StartSectorh
|
||
|
|
mov ax,StartSectorl ; dx:ax = lba start sector
|
||
|
|
div cx ; dx = sector within cylinder
|
||
|
|
mov ax,dx ; ax = sector within cylinder
|
||
|
|
div [si].Int13SectorsPerTrack ; ah = sector in track
|
||
|
|
mov al,[si].Int13SectorsPerTrack
|
||
|
|
sub al,ah ; al = sectors left in track
|
||
|
|
cbw ; ah = 0
|
||
|
|
|
||
|
|
nexttrack:
|
||
|
|
cmp al,SectorCount ; see if we need that many
|
||
|
|
jbe @f
|
||
|
|
mov al,SectorCount
|
||
|
|
|
||
|
|
@@: push Buffer
|
||
|
|
push ax ; al = count, ah = 0
|
||
|
|
mov di,ax ; save sector count
|
||
|
|
push StartSector
|
||
|
|
push ds
|
||
|
|
push si
|
||
|
|
call IoRoutine
|
||
|
|
add sp,14
|
||
|
|
cmp ax,0
|
||
|
|
jz iodone ; ax already 0 for error exit
|
||
|
|
|
||
|
|
mov ax,di ; al = #sectors we just read, ah = 0
|
||
|
|
add StartSectorl,ax ; adjust start sector
|
||
|
|
adc StartSectorh,0
|
||
|
|
sub SectorCount,al ; adjust sector count
|
||
|
|
jz iodone ; ax already non-0 for success return
|
||
|
|
|
||
|
|
;
|
||
|
|
; To avoid segment wraps, we'll do arithmetic on the segment
|
||
|
|
; instead of the offset. The maximum number of sectors per track
|
||
|
|
; is 3fh. Each sector is 200h bytes, which expressed as the offset
|
||
|
|
; to the next segment is 20h = 2^5. Thus shifting the sector count
|
||
|
|
; left by 5 yields a result between 20h and 7e0h, which we add
|
||
|
|
; to the segment of the transfer address.
|
||
|
|
;
|
||
|
|
; Note that at this point ah = 0.
|
||
|
|
;
|
||
|
|
shl ax,5
|
||
|
|
add Bufferh,ax
|
||
|
|
|
||
|
|
mov al,[si].Int13SectorsPerTrack
|
||
|
|
cbw ; ax = whole track for next read
|
||
|
|
jmp short nexttrack
|
||
|
|
|
||
|
|
iodone:
|
||
|
|
pop di
|
||
|
|
pop si
|
||
|
|
pop bx
|
||
|
|
pop es
|
||
|
|
pop ds
|
||
|
|
|
||
|
|
leave
|
||
|
|
retf
|
||
|
|
|
||
|
|
Int13DiskIo endp
|
||
|
|
|
||
|
|
|
||
|
|
;++
|
||
|
|
;
|
||
|
|
; ULONG
|
||
|
|
; _far
|
||
|
|
; pGetExtendedInt13SectorCount(
|
||
|
|
; IN BYTE Int13Unit
|
||
|
|
; );
|
||
|
|
;
|
||
|
|
; Routine Description:
|
||
|
|
;
|
||
|
|
; This routine determines the number of sectors available on an int13
|
||
|
|
; disk via extended int13 services.
|
||
|
|
;
|
||
|
|
; Arguments:
|
||
|
|
;
|
||
|
|
; Int13Unit - supplies the int13 unit # for the disk.
|
||
|
|
;
|
||
|
|
; Return Value:
|
||
|
|
;
|
||
|
|
; 0 - extended int13 services not available for drive.
|
||
|
|
; non-0 - number of sectors available for i/o via xint13 on the drive.
|
||
|
|
;
|
||
|
|
;--
|
||
|
|
|
||
|
|
Int13Unit equ byte ptr [bp+6]
|
||
|
|
|
||
|
|
pGetExtendedInt13SectorCount proc far
|
||
|
|
|
||
|
|
push bp
|
||
|
|
mov bp,sp
|
||
|
|
sub sp,26
|
||
|
|
|
||
|
|
push ds
|
||
|
|
push es
|
||
|
|
push bx
|
||
|
|
push si
|
||
|
|
push di
|
||
|
|
|
||
|
|
;
|
||
|
|
; See if xint13 is disabled for this unit.
|
||
|
|
;
|
||
|
|
push DGROUP
|
||
|
|
pop ds
|
||
|
|
mov si,OFFSET DGROUP:xInt13DisableTable
|
||
|
|
mov al,Int13Unit
|
||
|
|
and al,7fh
|
||
|
|
cbw ; ah = 0
|
||
|
|
mov bx,ax ; bh = 0
|
||
|
|
and al,7 ; al = bit offset within byte
|
||
|
|
shr bl,3 ; bx = offset to byte
|
||
|
|
bt [si+bx],al ; see if disabled bit set
|
||
|
|
jc notpresent ; bit set, don't use xint13
|
||
|
|
|
||
|
|
;
|
||
|
|
; check extensions present
|
||
|
|
;
|
||
|
|
mov ah,41h
|
||
|
|
mov bx,55aah
|
||
|
|
mov dl,Int13Unit
|
||
|
|
int 13h
|
||
|
|
jc notpresent
|
||
|
|
cmp bx,0aa55h
|
||
|
|
jne notpresent
|
||
|
|
test cx,1
|
||
|
|
jz notpresent
|
||
|
|
|
||
|
|
;
|
||
|
|
; now we think the extensions are present, go get
|
||
|
|
; extended geometry. Note that there are plenty of
|
||
|
|
; broken BIOSes out there that will return success to this
|
||
|
|
; call even though they don't really support extended int13.
|
||
|
|
; So we zero out the buffer ourselves first. If the BIOS
|
||
|
|
; doesn't fill the buffer the extended sector count will
|
||
|
|
; be returned as zero, which is what we want.
|
||
|
|
;
|
||
|
|
mov ax,ss
|
||
|
|
mov ds,ax
|
||
|
|
mov es,ax
|
||
|
|
lea di,[bp-24] ; don't bother with first word (size)
|
||
|
|
xor ax,ax
|
||
|
|
mov cx,12 ; 24 bytes
|
||
|
|
cld
|
||
|
|
rep stosw
|
||
|
|
lea si,[bp-26]
|
||
|
|
mov word ptr [si],26 ; set up size of info buffer
|
||
|
|
|
||
|
|
mov ah,48h
|
||
|
|
mov dl,Int13Unit
|
||
|
|
int 13h
|
||
|
|
jc notpresent
|
||
|
|
|
||
|
|
;
|
||
|
|
; OK, everything worked, return sector count.
|
||
|
|
;
|
||
|
|
mov ax,[bp-10]
|
||
|
|
mov dx,[bp-8]
|
||
|
|
jmp short xdone
|
||
|
|
|
||
|
|
notpresent:
|
||
|
|
xor ax,ax
|
||
|
|
mov dx,ax
|
||
|
|
|
||
|
|
xdone:
|
||
|
|
pop di
|
||
|
|
pop si
|
||
|
|
pop bx
|
||
|
|
pop es
|
||
|
|
pop ds
|
||
|
|
leave
|
||
|
|
ret
|
||
|
|
|
||
|
|
pGetExtendedInt13SectorCount endp
|
||
|
|
|
||
|
|
|
||
|
|
;++
|
||
|
|
;
|
||
|
|
; VOID
|
||
|
|
; _far
|
||
|
|
; DisableExtendedInt13(
|
||
|
|
; IN BYTE Int13Unit OPTIONAL
|
||
|
|
; );
|
||
|
|
;
|
||
|
|
; Routine Description:
|
||
|
|
;
|
||
|
|
; This routine disables use of extended int13 services on a particular
|
||
|
|
; int13 disk unit, or for all int13 disk units. This works by forcing
|
||
|
|
; the extended sector count to 0, which in a chain reaction ensures
|
||
|
|
; that no one will ever invoke an xint13 service for that unit.
|
||
|
|
;
|
||
|
|
; This routine MUST be called before InitializeDiskList or it will
|
||
|
|
; have no effect!
|
||
|
|
;
|
||
|
|
; Arguments:
|
||
|
|
;
|
||
|
|
; Int13Unit - supplies the int13 unit # on which to disable xint13.
|
||
|
|
; (The high bit is assumed set and ignored.) If this value
|
||
|
|
; is 0, xint13 is disabled for all drives.
|
||
|
|
;
|
||
|
|
; Return Value:
|
||
|
|
;
|
||
|
|
; None.
|
||
|
|
;
|
||
|
|
;--
|
||
|
|
|
||
|
|
Int13Unit equ byte ptr [bp+6]
|
||
|
|
|
||
|
|
public _DisableExtendedInt13
|
||
|
|
_DisableExtendedInt13 proc far
|
||
|
|
|
||
|
|
push bp
|
||
|
|
mov bp,sp
|
||
|
|
|
||
|
|
push es
|
||
|
|
push bx
|
||
|
|
push di
|
||
|
|
|
||
|
|
;
|
||
|
|
; Address the xint13 disabled list table.
|
||
|
|
;
|
||
|
|
push DGROUP
|
||
|
|
pop es
|
||
|
|
mov di,OFFSET DGROUP:xInt13DisableTable
|
||
|
|
|
||
|
|
;
|
||
|
|
; See if we're supposed to disable for all disks.
|
||
|
|
;
|
||
|
|
mov al,Int13Unit
|
||
|
|
cmp al,0
|
||
|
|
jz allunits
|
||
|
|
|
||
|
|
;
|
||
|
|
; One unit only, take care of it here.
|
||
|
|
;
|
||
|
|
and al,7fh
|
||
|
|
cbw ; ah = 0
|
||
|
|
mov bx,ax ; bh = 0
|
||
|
|
and al,7 ; al = bit offset within byte
|
||
|
|
shr bl,3 ; bx = offset to byte
|
||
|
|
bts es:[di+bx],al
|
||
|
|
jmp dxidone
|
||
|
|
|
||
|
|
allunits:
|
||
|
|
;
|
||
|
|
; Set all bits in the table to 1
|
||
|
|
;
|
||
|
|
cbw ; ax = 0
|
||
|
|
dec ax ; ax = ff
|
||
|
|
mov cx,8 ; 8 words = 16 bytes = 128 bits
|
||
|
|
cld
|
||
|
|
rep stosw
|
||
|
|
|
||
|
|
dxidone:
|
||
|
|
pop di
|
||
|
|
pop bx
|
||
|
|
pop es
|
||
|
|
leave
|
||
|
|
ret
|
||
|
|
|
||
|
|
_DisableExtendedInt13 endp
|
||
|
|
|
||
|
|
|
||
|
|
;++
|
||
|
|
;
|
||
|
|
; VOID
|
||
|
|
; _far
|
||
|
|
; GetInt13DiskInfo(
|
||
|
|
; IN FPINT13_DISK_INFO DiskRecord,
|
||
|
|
; OUT FPBYTE Int13UnitNumber,
|
||
|
|
; OUT FPBYTE SectorsPerTrack,
|
||
|
|
; OUT FPUSHORT Heads,
|
||
|
|
; OUT FPUSHORT Cylinders,
|
||
|
|
; OUT FPULONG ExtendedSectorCount
|
||
|
|
; );
|
||
|
|
;
|
||
|
|
; Routine Description:
|
||
|
|
;
|
||
|
|
; These routines fetches information about a disk.
|
||
|
|
;
|
||
|
|
; Arguments:
|
||
|
|
;
|
||
|
|
; Return Value:
|
||
|
|
;
|
||
|
|
; None.
|
||
|
|
;
|
||
|
|
;--
|
||
|
|
|
||
|
|
DiskRecord equ dword ptr [bp+6]
|
||
|
|
Int13UnitNumber equ dword ptr [bp+10]
|
||
|
|
SectorsPerTrack equ dword ptr [bp+14]
|
||
|
|
Heads equ dword ptr [bp+18]
|
||
|
|
Cylinders equ dword ptr [bp+22]
|
||
|
|
ExtendedSecCnt equ dword ptr [bp+26]
|
||
|
|
|
||
|
|
public GetInt13DiskInfo
|
||
|
|
GetInt13DiskInfo proc far
|
||
|
|
|
||
|
|
push bp
|
||
|
|
mov bp,sp
|
||
|
|
|
||
|
|
push ds
|
||
|
|
push es
|
||
|
|
push si
|
||
|
|
push di
|
||
|
|
|
||
|
|
lds si,DiskRecord
|
||
|
|
add si,Int13DiskUnit
|
||
|
|
cld
|
||
|
|
|
||
|
|
les di,Int13UnitNumber
|
||
|
|
movsb
|
||
|
|
|
||
|
|
.errnz (Int13SectorsPerTrack - Int13DiskUnit) - 1
|
||
|
|
les di,SectorsPerTrack
|
||
|
|
movsb
|
||
|
|
|
||
|
|
.errnz (Int13Heads - Int13SectorsPerTrack) - 1
|
||
|
|
les di,Heads
|
||
|
|
movsw
|
||
|
|
|
||
|
|
.errnz (Int13Cylinders - Int13Heads) - 2
|
||
|
|
les di,Cylinders
|
||
|
|
movsw
|
||
|
|
|
||
|
|
.errnz (Int13xSectorCountl - Int13Cylinders) - 2
|
||
|
|
les di,ExtendedSecCnt
|
||
|
|
movsw
|
||
|
|
movsw
|
||
|
|
|
||
|
|
pop di
|
||
|
|
pop si
|
||
|
|
pop es
|
||
|
|
pop ds
|
||
|
|
|
||
|
|
leave
|
||
|
|
retf
|
||
|
|
|
||
|
|
GetInt13DiskInfo endp
|
||
|
|
|
||
|
|
end
|