Copyright (c) Hyperion Entertainment and contributors.
Example Device
Revision as of 15:26, 12 April 2012 by Alexandre Balaban (talk | contribs) (Added to need code review category)
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Code samples on this page are not yet updated to AmigaOS 4.x some of them may be obsolete or incompatible with AmigaOS 4.x. |
Example Device
This appendix contains source code for a sample device. The example code is an excellent starting point for those who want to create a custom device and add it to the Amiga’s system software.
The example is a complete four-unit, static-sized RAM disk that works under the old (standard) filing system, the new Fast Filing System (FFS), and has optional code to bind it to an AUTOCONFIG device.
The examples have been assembled under the Metacomco assembler V11.0 and under the CAPE assembler V2.0.
ramdev-mountlist
/*
* Mountlist for manually mounting the sample ramdisk driver.
*
* F0: and F1: are set up for the V1.3 fast file system (FFS).
* S2: and S3: are setup for the old file system (OFS).
*
* After mounting, the drives must be formatted. Be sure to
* use the FFS flag when formatting the Fast File System
* ramdrives:
*
* ;make sure "ramdev.device" is in DEVS:
*
* mount f0: from mydev-mountlist
* format drive f0: name "Zippy" FFS
*/
F0: Device = ramdev.device
Unit = 0
LowCyl = 0 ; HighCyl = 14
Surfaces = 1
Buffers = 1
BlocksPerTrack = 10
Flags = 0
Reserved = 2
GlobVec = -1
BufMemType = 0
DosType = 0x444F5301
StackSize = 4000
FileSystem = l:fastfilesystem
#
F1: Device = ramdev.device
Unit = 1
LowCyl = 0 ; HighCyl = 14
Surfaces = 1
Buffers = 1
BlocksPerTrack = 10
Flags = 0
Reserved = 2
GlobVec = -1
BufMemType = 0
DosType = 0x444F5301
StackSize = 4000
FileSystem = l:fastfilesystem
#
S2: Device = ramdev.device
Unit = 2
Flags = 0
Surfaces = 1
BlocksPerTrack = 10
Reserved = 1
Interleave = 0
LowCyl = 0 ; HighCyl = 14
Buffers = 1
BufMemType = 0
#
S3: Device = ramdev.device
Unit = 3
Flags = 0
Surfaces = 1
BlocksPerTrack = 10
Reserved = 1
Interleave = 0
LowCyl = 0 ; HighCyl = 14
Buffers = 1
BufMemType = 0
#
ramdev.i
******************************************************************
*
*
* Copyright (C) 1986, Commodore Amiga Inc. All rights reserved.
* Permission granted for non-commercial use
*
*****************************************************************
*
* ramdev.i -- external declarations for skeleton ramdisk device
*
*****************************************************************
;--- Assemble-time options
INFO_LEVEL EQU 0 ; Specify amount of debugging info desired
; If > 0 you must link with debug.lib!
; You will need to run a terminal program to
; set the baud rate.
*INTRRUPT SET 1 ; Remove "*" to enable fake interrupt code
AUTOMOUNT EQU 0 ; Work with the "mount" command if 0
; Do it automatically if 1
;--- stack size and priority for the process we will create
MYPROCSTACKSIZE EQU $900
MYPROCPRI EQU 0 ;Devices are often 5, NOT higher
;--- Base constants
NUMBEROFTRACKS EQU 40 ;<<<< Change THIS to change size of ramdisk <<<<
SECTOR EQU 512 ;# bytes per sector
SECSHIFT EQU 9 ;Shift count to convert byte # to sector #
SECTORSPER EQU 10 ;# Sectors per "track"
RAMSIZE EQU SECTOR*NUMBEROFTRACKS*SECTORSPER
; Use this much RAM per unit
BYTESPERTRACK EQU SECTORSPER*SECTOR
IAMPULLING EQU 7 ; "I am pulling the interrupt" bit of INTCRL1
INTENABLE EQU 4 ; "Interrupt Enable" bit of INTCRL2
INTCTRL1 EQU $40 ; Interrupt control register offset on board
INTCTRL2 EQU $42 ; Interrupt control register offset on board
INTACK EQU $50 ; My board's interrupt reset address
;-----------------------------------------------------------------------
;
; device command definitions (copied from devices/trackdisk.i)
;
;-----------------------------------------------------------------------
BITDEF TD,EXTCOM,15 ; for "extended" commands !!!
DEVINIT
DEVCMD CMD_MOTOR ; control the disk's motor (NO-OP)
DEVCMD CMD_SEEK ; explicit seek (NO-OP)
DEVCMD CMD_FORMAT ; format disk - equated to WRITE for RAMDISK
DEVCMD CMD_REMOVE ; notify when disk changes (NO-OP)
DEVCMD CMD_CHANGENUM ; number of disk changes (always 0)
DEVCMD CMD_CHANGESTATE ; is there a disk in the drive? (always TRUE)
DEVCMD CMD_PROTSTATUS ; is the disk write protected? (always FALSE)
DEVCMD CMD_RAWREAD ; Not supported
DEVCMD CMD_RAWWRITE ; Not supported
DEVCMD CMD_GETDRIVETYPE ; Get drive type
DEVCMD CMD_GETNUMTRACKS ; Get number of tracks
DEVCMD CMD_ADDCHANGEINT ; Add disk change interrupt (NO-OP)
DEVCMD CMD_REMCHANGEINT ; Remove disk change interrupt ( NO-OP)
DEVCMD MYDEV_END ; place marker -- first illegal command #
DRIVE3_5 EQU 1
DRIVE5_25 EQU 2
;-----------------------------------------------------------------------
;
; Layout of parameter packet for MakeDosNode
;
;-----------------------------------------------------------------------
STRUCTURE MkDosNodePkt,0
APTR mdn_dosName ; Pointer to DOS file handler name
APTR mdn_execName ; Pointer to device driver name
ULONG mdn_unit ; Unit number
ULONG mdn_flags ; OpenDevice flags
ULONG mdn_tableSize ; Environment size
ULONG mdn_sizeBlock ; # longwords in a block
ULONG mdn_secOrg ; sector origin -- unused
ULONG mdn_numHeads ; number of surfaces
ULONG mdn_secsPerBlk ; secs per logical block -- unused
ULONG mdn_blkTrack ; secs per track
ULONG mdn_resBlks ; reserved blocks -- MUST be at least 1!
ULONG mdn_prefac ; unused
ULONG mdn_interleave ; interleave
ULONG mdn_lowCyl ; lower cylinder
ULONG mdn_upperCyl ; upper cylinder
ULONG mdn_numBuffers ; number of buffers
ULONG mdn_memBufType ; Type of memory for AmigaDOS buffers
STRUCT mdn_dName,5 ; DOS file handler name "RAM0"
LABEL mdn_Sizeof ; Size of this structure
;-----------------------------------------------------------------------
;
; device data structures
;
;-----------------------------------------------------------------------
; maximum number of units in this device
MD_NUMUNITS EQU 4
STRUCTURE MyDev,LIB_SIZE
UBYTE md_Flags
UBYTE md_Pad1
;now longword aligned
ULONG md_SysLib
ULONG md_SegList
ULONG md_Base ; Base address of this device's expansion board
STRUCT md_Units,MD_NUMUNITS*4
LABEL MyDev_Sizeof
STRUCTURE MyDevUnit,UNIT_SIZE ;Odd # longwords
UBYTE mdu_UnitNum
UBYTE mdu_SigBit ; Signal bit allocated for interrupts
;Now longword aligned!
APTR mdu_Device
STRUCT mdu_stack,MYPROCSTACKSIZE
STRUCT mdu_tcb,TC_SIZE ; Task Control Block (TCB) for disk task
ULONG mdu_SigMask ; Signal these bits on interrupt
IFD INTRRUPT
STRUCT mdu_is,IS_SIZE ; Interrupt structure
UWORD mdu_pad1 ;Longword align
ENDC
STRUCT mdu_RAM,RAMSIZE ; RAM used to simulate disk
LABEL MyDevUnit_Sizeof
;------ state bit for unit stopped
BITDEF MDU,STOPPED,2
MYDEVNAME MACRO
DC.B 'ramdev.device',0
ENDM
asmsupp.i
*************************************************************************
*
* Copyright (C) 1985, Commodore Amiga Inc. All rights reserved.
* Permission granted for non-commercial use
*
* asmsupp.i -- random low level assembly support routines
* used by the Commodore sample Library & Device
*
*************************************************************************
CLEAR MACRO ;quick way to clear a D register on 68000
MOVEQ #0,\1
ENDM
;BHS MACRO
; BCC.\0 \1 ;\0 is the extension used on the macro (such as ".s")
; ENDM
;BLO MACRO
; BCS.\0 \1
; ENDM
;EVEN MACRO ; word align code stream
; DS.W 0
; ENDM
LINKSYS MACRO ; link to a library without having to see a _LVO
MOVE.L A6,-(SP)
MOVE.L \2,A6
JSR _LVO\1(A6)
MOVE.L (SP)+,A6
ENDM
CALLSYS MACRO ; call a library via A6 without having to see _LVO
JSR _LVO\1(A6)
ENDM
XLIB MACRO ; define a library reference without the _LVO
XREF _LVO\1
ENDM
;
; Put a message to the serial port at 9600 baud. Used as so:
;
; PUTMSG 30,<'%s/Init: called'>
;
; Parameters can be printed out by pushing them on the stack and
; adding the appropriate C printf-style % formatting commands.
;
XREF KPutFmt
PUTMSG: MACRO * level,msg
IFGE INFO_LEVEL-\1
PEA subSysName(PC)
MOVEM.L A0/A1/D0/D1,-(SP)
LEA msg\@(pc),A0 ;Point to static format string
LEA 4*4(SP),A1 ;Point to args
JSR KPutFmt
MOVEM.L (SP)+,D0/D1/A0/A1
ADDQ.L #4,SP
BRA.S end\@
msg\@ DC.B \2
DC.B 10
DC.B 0
DS.W 0
end\@
ENDC
ENDM
ramdev.device.asm
*************************************************************************
*
* Copyright (C) 1986,1988,1989 Commodore Amiga Inc. All rights reserved.
* Permission granted for non-commercial use.
*
*************************************************************************
*
* ramdev.asm -- Skeleton device code.
*
* A sample 4 unit ramdisk that can be bound to an expansion slot device,
* or used without. Works with the Fast File System.
* This code is required reading for device driver writers. It contains
* information not found elsewhere. This code is somewhat old; you probably
* don't want to copy it directly.
*
* This example includes a task, though a task is not actually needed for
* a simple ram disk. Unlike a single set of hardware registers that
* may need to be shared by multiple tasks, ram can be freely shared.
* This example does not show arbitration of hardware resources.
*
* Tested with CAPE and Metacomco
*
* Based on mydev.asm
* 10/07/86 Modified by Lee Erickson to be a simple disk device
* using RAM to simulate a disk.
* 02/02/88 Modified by C. Scheppner, renamed ramdev
* 09/28/88 Repaired by Bryce Nesbitt for new release
* 11/02/88 More clarifications
* 02/01/89 Even more clarifications & warnings
* 02/22/89 START/STOP fix from Marco Papa
*
* Bugs: If RTF_AUTOINIT fails, library base still left in memory.
*
*************************************************************************
SECTION firstsection
NOLIST
include "exec/types.i"
include "exec/devices.i"
include "exec/initializers.i"
include "exec/memory.i"
include "exec/resident.i"
include "exec/io.i"
include "exec/ables.i"
include "exec/errors.i"
include "exec/tasks.i"
include "hardware/intbits.i"
include "asmsupp.i" ;standard asmsupp.i, same as used for library
include "ramdev.i"
IFNE AUTOMOUNT
include "libraries/expansion.i"
include "libraries/configvars.i"
include "libraries/configregs.i"
ENDC
LIST
ABSEXECBASE equ 4 ;Absolute location of the pointer to exec.library base
;------ These don't have to be external, but it helps some
;------ debuggers to have them globally visible
XDEF Init
XDEF Open
XDEF Close
XDEF Expunge
XDEF Null
XDEF myName
XDEF BeginIO
XDEF AbortIO
;Pull these _LVOs in from amiga.lib
XLIB AddIntServer
XLIB RemIntServer
XLIB Debug
XLIB InitStruct
XLIB OpenLibrary
XLIB CloseLibrary
XLIB Alert
XLIB FreeMem
XLIB Remove
XLIB AddPort
XLIB AllocMem
XLIB AddTask
XLIB PutMsg
XLIB RemTask
XLIB ReplyMsg
XLIB Signal
XLIB GetMsg
XLIB Wait
XLIB WaitPort
XLIB AllocSignal
XLIB SetTaskPri
XLIB GetCurrentBinding ;Use to get list of boards for this driver
XLIB MakeDosNode
XLIB AddDosNode
XLIB CopyMemQuick ;Highly optimized copy function from exec.library
INT_ABLES ;Macro from exec/ables.i
;-----------------------------------------------------------------------
; The first executable location. This should return an error
; in case someone tried to run you as a program (instead of
; loading you as a device).
FirstAddress:
moveq #-1,d0
rts
;-----------------------------------------------------------------------
; A romtag structure. After your driver is brought in from disk, the
; disk image will be scanned for this structure to discover magic constants
; about you (such as where to start running you from...).
;-----------------------------------------------------------------------
; Most people will not need a priority and should leave it at zero.
; the RT_PRI field is used for configuring the roms. Use "mods" from
; wack to look at the other romtags in the system
MYPRI EQU 0
initDDescrip:
;STRUCTURE RT,0
DC.W RTC_MATCHWORD ; UWORD RT_MATCHWORD (Magic cookie)
DC.L initDDescrip ; APTR RT_MATCHTAG (Back pointer)
DC.L EndCode ; APTR RT_ENDSKIP (To end of this hunk)
DC.B RTF_AUTOINIT ; UBYTE RT_FLAGS (magic-see "Init:")
DC.B VERSION ; UBYTE RT_VERSION
DC.B NT_DEVICE ; UBYTE RT_TYPE (must be correct)
DC.B MYPRI ; BYTE RT_PRI
DC.L myName ; APTR RT_NAME (exec name)
DC.L idString ; APTR RT_IDSTRING (text string)
DC.L Init ; APTR RT_INIT
; LABEL RT_SIZE
;This name for debugging use
IFNE INFO_LEVEL ;If any debugging enabled at all
subSysName:
dc.b "ramdev",0
ENDC
; this is the name that the device will have
myName: MYDEVNAME
IFNE AUTOMOUNT
ExLibName dc.b 'expansion.library',0 ; Expansion Library Name
ENDC
; a major version number.
VERSION: EQU 37
; A particular revision. This should uniquely identify the bits in the
; device. I use a script that advances the revision number each time
; I recompile. That way there is never a question of which device
; that really is.
REVISION: EQU 1
; this is an identifier tag to help in supporting the device
; format is 'name version.revision (d.m.yy)',<cr>,<lf>,<null>
idString: dc.b 'ramdev 37.1 (28.8.91)',13,10,0
; force word alignment
ds.w 0
; The romtag specified that we were "RTF_AUTOINIT". This means
; that the RT_INIT structure member points to one of these
; tables below. If the AUTOINIT bit was not set then RT_INIT
; would point to a routine to run.
Init:
DC.L MyDev_Sizeof ; data space size
DC.L funcTable ; pointer to function initializers
DC.L dataTable ; pointer to data initializers
DC.L initRoutine ; routine to run
funcTable:
;------ standard system routines
dc.l Open
dc.l Close
dc.l Expunge
dc.l Null ;Reserved for future use!
;------ my device definitions
dc.l BeginIO
dc.l AbortIO
;------ custom extended functions
dc.l FunctionA
dc.l FunctionB
;------ function table end marker
dc.l -1
;The data table initializes static data structures. The format is
;specified in exec/InitStruct routine's manual pages. The
;INITBYTE/INITWORD/INITLONG macros are in the file "exec/initializers.i".
;The first argument is the offset from the device base for this
;byte/word/long. The second argument is the value to put in that cell.
;The table is null terminated
;
dataTable:
INITBYTE LN_TYPE,NT_DEVICE ;Must be LN_TYPE!
INITLONG LN_NAME,myName
INITBYTE LIB_FLAGS,LIBF_SUMUSED!LIBF_CHANGED
INITWORD LIB_VERSION,VERSION
INITWORD LIB_REVISION,REVISION
INITLONG LIB_IDSTRING,idString
DC.W 0 ;terminate list
;-------- initRoutine -------------------------------------------------------
;
; FOR RTF_AUTOINIT:
; This routine gets called after the device has been allocated.
; The device pointer is in D0. The AmigaDOS segment list is in a0.
; If it returns the device pointer, then the device will be linked
; into the device list. If it returns NULL, then the device
; will be unloaded.
;
; IMPORTANT:
; If you don't use the "RTF_AUTOINIT" feature, there is an additional
; caveat. If you allocate memory in your Open function, remember that
; allocating memory can cause an Expunge... including an expunge of your
; device. This must not be fatal. The easy solution is don't add your
; device to the list until after it is ready for action.
;
; This call is single-threaded by exec; please read the description for
; "Open" below.
;
; Register Usage
; ==============
; a3 -- Points to temporary RAM
; a4 -- Expansion library base
; a5 -- device pointer
; a6 -- Exec base
;----------------------------------------------------------------------
initRoutine:
;------ get the device pointer into a convenient A register
PUTMSG 5,<'%s/Init: called'>
movem.l d1-d7/a0-a5,-(sp) ; Preserve ALL modified registers
move.l d0,a5
;------ save a pointer to exec
move.l a6,md_SysLib(a5) ;faster access than move.l 4,a6
;------ save pointer to our loaded code (the SegList)
move.l a0,md_SegList(a5)
IFNE AUTOMOUNT
**************************************************************************
*
* Here starts the AutoConfig stuff. If this driver was to be tied to
* an expansion board, you would put this driver in the expansion drawer,
* and be called when BindDrivers finds a board that matches this driver.
* The Commodore-Amiga assigned product number of your board must be
* specified in the "PRODUCT=" field in the TOOLTYPES of this driver's icon.
* GetCurrentBinding() returns your (first) board.
*
lea.l ExLibName,A1 ; Get expansion lib. name
moveq.l #0,D0
CALLSYS OpenLibrary ; Open the expansion library
tst.l D0
beq Init_Error
;------ init_OpSuccess:
move.l D0,A4 ;[expansionbase to A4]
moveq #0,D3
lea md_Base(A5),A0 ; Get the Current Bindings
moveq #4,D0 ; Just get address (length = 4 bytes)
LINKLIB _LVOGetCurrentBinding,A4
move.l md_Base(A5),D0 ; Get start of list
tst.l D0 ; If controller not found
beq Init_End ; Exit and unload driver
PUTMSG 10,<'%s/Init: GetCurrentBinding returned non-zero'>
move.l D0,A0 ; Get config structure address
move.l cd_BoardAddr(A0),md_Base(A5); Save board base address
bclr.b #CDB_CONFIGME,cd_Flags(A0); Mark board as configured
;----------------------------------------------------------------------
;
; Here we build a packet describing the characteristics of our disk to
; pass to AmigaDOS. This serves the same purpose as a "mount" command
; of this device would. For disks, it might be useful to actually
; get this information right from the disk itself. Just as mount,
; it could be for multiple partitions on the single physical device.
; For this example, we will simply hard code the appropriate parameters.
;
; The AddDosNode call adds things to dos's list without needing to
; use mount. We'll mount all 4 of our units whenever we are
; started.
;
;-----------------------------------------------------------------------
;!!! If your card was successfully configured, you can mount the
;!!! units as DOS nodes
;------ Allocate temporary RAM to build MakeDosNode parameter packet
move.l #MEMF_CLEAR!MEMF_PUBLIC,d1
move.l #mdn_Sizeof,d0 ; Enough room for our parameter packet
CALLSYS AllocMem
move.l d0,a3 ;:BUG: AllocMem error not checked here.
;----- Use InitStruct to initialize the constant portion of packet
move.l d0,a2 ; Point to memory to initialize
moveq.l #0,d0 ; Don't need to re-zero it
lea.l mdn_Init(pc),A1
CALLSYS InitStruct
lea mdn_dName(a3),a0 ; Get addr of Device name
move.l a0,mdn_dosName(a3) ; and save in environment
moveq #0,d6 ; Now tell AmigaDOS about all units UNITNUM
Uloop:
move.b d6,d0 ; Get unit number
add.b #$30,d0 ; Make ASCII, minus 1
move.b d0,mdn_dName+2(a3) ; and store in name
move.l d6,mdn_unit(a3) ; Store unit # in environment
;
;! Before adding to the dos list, you should really check if you
;! are about to cause a name collision. This example does not.
;
move.l a3,a0
LINKLIB _LVOMakeDosNode,a4 ; Build AmigaDOS structures
;This can fail, but so what?
move.l d0,a0 ; Get deviceNode address
moveq.l #0,d0 ; Set device priority to 0
moveq.l #0,d1
* moveq.l #ADNF_STARTPROC,d1 ; See note below
;It's ok to pass a zero in here
LINKLIB _LVOAddDosNode,a4
; ADNF_STARTPROC will work, but only if dn_SegList is filled in
; in the SegPtr of the handler task.
addq #1,d6 ; Bump unit number
cmp.b #MD_NUMUNITS,d6
bls.s Uloop ; Loop until all units installed
move.l a3,a1 ; Return RAM to system
move.l #mdn_Sizeof,d0
CALLSYS FreeMem
Init_End:
move.l a4,a1 ; Now close expansion library
CALLSYS CloseLibrary
*
* You would normally set d0 to a NULL if your initialization failed,
* but I'm not doing that for this demo, since it is unlikely
* you actually have a board with any particular manufacturer ID
* installed when running this demo.
*************************************************************************
ENDC
move.l a5,d0
Init_Error:
movem.l (sp)+,d1-d7/a0-a5
rts
;----------------------------------------------------------------------
;
; Here begins the system interface commands. When the user calls
; OpenDevice/CloseDevice/RemDevice, this eventually gets translated
; into a call to the following routines (Open/Close/Expunge).
; Exec has already put our device pointer in a6 for us.
;
; IMPORTANT:
; These calls are guaranteed to be single-threaded; only one task
; will execute your Open/Close/Expunge at a time.
;
; For Kickstart V33/34, the single-threading method involves "Forbid".
; There is a good chance this will change. Anything inside your
; Open/Close/Expunge that causes a direct or indirect Wait() will break
; the Forbid(). If the Forbid() is broken, some other task might
; manage to enter your Open/Close/Expunge code at the same time.
; Take care!
;
; Since exec has turned off task switching while in these routines
; (via Forbid/Permit), we should not take too long in them.
;
;----------------------------------------------------------------------
; Open sets the IO_ERROR field on an error. If it was successfull,
; we should also set up the IO_UNIT and LN_TYPE fields.
; exec takes care of setting up IO_DEVICE.
Open: ; ( device:a6, iob:a1, unitnum:d0, flags:d1 )
;** Subtle point: any AllocMem() call can cause a call to this device's
;** expunge vector. If LIB_OPENCNT is zero, the device might get expunged.
addq.w #1,LIB_OPENCNT(a6) ;Fake an opener for duration of call <|>
PUTMSG 20,<'%s/Open: called'>
movem.l d2/a2/a3/a4,-(sp)
move.l a1,a2 ; save the iob
;------ see if the unit number is in range *!* UNIT 0 to 3 *!*
cmp.l #MD_NUMUNITS,d0
bcc.s Open_Range_Error ; unit number out of range (BHS)
;------ see if the unit is already initialized
move.l d0,d2 ; save unit number
lsl.l #2,d0
lea.l md_Units(a6,d0.l),a4
move.l (a4),d0
bne.s Open_UnitOK
;------ try and conjure up a unit
bsr InitUnit ;scratch:a3 unitnum:d2 devpoint:a6
;------ see if it initialized OK
move.l (a4),d0
beq.s Open_Error
Open_UnitOK:
move.l d0,a3 ; unit pointer in a3
move.l d0,IO_UNIT(a2)
;------ mark us as having another opener
addq.w #1,LIB_OPENCNT(a6)
addq.w #1,UNIT_OPENCNT(a3) ;Internal bookkeeping
;------ prevent delayed expunges
bclr #LIBB_DELEXP,md_Flags(a6)
CLEAR d0
move.b d0,IO_ERROR(a2)
move.b #NT_REPLYMSG,LN_TYPE(a2) ;IMPORTANT: Mark IORequest as "complete"
Open_End:
subq.w #1,LIB_OPENCNT(a6) ;** End of expunge protection <|>
movem.l (sp)+,d2/a2/a3/a4
rts
Open_Range_Error:
Open_Error:
moveq #IOERR_OPENFAIL,d0
move.b d0,IO_ERROR(a2)
move.l d0,IO_DEVICE(a2) ;IMPORTANT: trash IO_DEVICE on open failure
PUTMSG 2,<'%s/Open: failed'>
bra.s Open_End
;----------------------------------------------------------------------------
; There are two different things that might be returned from the Close
; routine. If the device wishes to be unloaded, then Close must return
; the segment list (as given to Init). Otherwise close MUST return NULL.
Close: ; ( device:a6, iob:a1 )
movem.l d1/a2-a3,-(sp)
PUTMSG 20,<'%s/Close: called'>
move.l a1,a2
move.l IO_UNIT(a2),a3
;------ IMPORTANT: make sure the IORequest is not used again
;------ with a -1 in IO_DEVICE, any BeginIO() attempt will
;------ immediatly halt (which is better than a subtle corruption
;------ that will lead to hard-to-trace crashes!!!!!!!!!!!!!!!!!!
moveq.l #-1,d0
move.l d0,IO_UNIT(a2) ;We're closed...
move.l d0,IO_DEVICE(a2) ;customers not welcome at this IORequest!!
;------ see if the unit is still in use
subq.w #1,UNIT_OPENCNT(a3)
;!!!!!! Since this example is a RAM disk (and we don't want the contents to
;!!!!!! disappear between opens, ExpungeUnit will be skipped here. It would
;!!!!!! be used for drivers of "real" devices
;!!!!!! bne.s Close_Device
;!!!!!! bsr ExpungeUnit
Close_Device:
CLEAR d0
;------ mark us as having one fewer openers
subq.w #1,LIB_OPENCNT(a6)
;------ see if there is anyone left with us open
bne.s Close_End
;------ see if we have a delayed expunge pending
btst #LIBB_DELEXP,md_Flags(a6)
beq.s Close_End
;------ do the expunge
bsr Expunge
Close_End:
movem.l (sp)+,d1/a2-a3
rts ;MUST return either zero or the SegList!!!
;------- Expunge -----------------------------------------------------------
;
; Expunge is called by the memory allocator when the system is low on
; memory.
;
; There are two different things that might be returned from the Expunge
; routine. If the device is no longer open then Expunge may return the
; segment list (as given to Init). Otherwise Expunge may set the
; delayed expunge flag and return NULL.
;
; One other important note: because Expunge is called from the memory
; allocator, it may NEVER Wait() or otherwise take long time to complete.
;
; A6 - library base (scratch)
; D0-D1/A0-A1 - scratch
;
Expunge: ; ( device: a6 )
PUTMSG 10,<'%s/Expunge: called'>
movem.l d1/d2/a5/a6,-(sp) ; Save ALL modified registers
move.l a6,a5
move.l md_SysLib(a5),a6
;------ see if anyone has us open
tst.w LIB_OPENCNT(a5)
;!!!!! The following line is commented out for this RAM disk demo, since
;!!!!! we don't want the RAM to be freed after FORMAT, for example.
; beq 1$
;------ it is still open. set the delayed expunge flag
bset #LIBB_DELEXP,md_Flags(a5)
CLEAR d0
bra.s Expunge_End
1$:
;------ go ahead and get rid of us. Store our seglist in d2
move.l md_SegList(a5),d2
;------ unlink from device list
move.l a5,a1
CALLSYS Remove ;Remove first (before FreeMem)
;
; device specific closings here...
;
;------ free our memory (must calculate from LIB_POSSIZE & LIB_NEGSIZE)
move.l a5,a1 ;Devicebase
CLEAR d0
move.w LIB_NEGSIZE(a5),d0
suba.l d0,a1 ;Calculate base of functions
add.w LIB_POSSIZE(a5),d0 ;Calculate size of functions + data area
CALLSYS FreeMem
;------ set up our return value
move.l d2,d0
Expunge_End:
movem.l (sp)+,d1/d2/a5/a6
rts
;------- Null ---------------------------------------------------------------
Null:
PUTMSG 1,<'%s/Null: called'>
CLEAR d0
rts ;The "Null" function MUST return NULL.
;------- Custom ------------------------------------------------------------
;
;Two "do nothing" device-specific functions
;
FunctionA:
add.l d1,d0 ;Add
rts
FunctionB:
add.l d0,d0 ;Double
rts
****************************************************************************
InitUnit: ; ( d2:unit number, a3:scratch, a6:devptr )
PUTMSG 30,<'%s/InitUnit: called'>
movem.l d2-d4/a2,-(sp)
;------ allocate unit memory
move.l #MyDevUnit_Sizeof,d0
move.l #MEMF_PUBLIC!MEMF_CLEAR,d1
LINKSYS AllocMem,md_SysLib(a6)
tst.l d0
beq InitUnit_End
move.l d0,a3
moveq.l #0,d0 ; Don't need to re-zero it
move.l a3,a2 ; InitStruct is initializing the UNIT
lea.l mdu_Init(pc),A1
LINKSYS InitStruct,md_SysLib(a6)
;!! IMPORTANT !!
move.l #42414400,mdu_RAM(a3) ;Mark offset zero as ASCII "BAD "
;!! IMPORTANT !!
move.b d2,mdu_UnitNum(a3) ;initialize unit number
move.l a6,mdu_Device(a3) ;initialize device pointer
;------ start up the unit task. We do a trick here --
;------ we set his message port to PA_IGNORE until the
;------ new task has a change to set it up.
;------ We cannot go to sleep here: it would be very nasty
;------ if someone else tried to open the unit
;------ (exec's OpenDevice has done a Forbid() for us --
;------ we depend on this to become single threaded).
;------ Initialize the stack information
lea mdu_stack(a3),a0 ; Low end of stack
move.l a0,mdu_tcb+TC_SPLOWER(a3)
lea MYPROCSTACKSIZE(a0),a0 ; High end of stack
move.l a0,mdu_tcb+TC_SPUPPER(a3)
move.l a3,-(A0) ; argument -- unit ptr (send on stack)
move.l a0,mdu_tcb+TC_SPREG(a3)
lea mdu_tcb(a3),a0
move.l a0,MP_SIGTASK(a3)
IFGE INFO_LEVEL-30
move.l a0,-(SP)
move.l a3,-(SP)
PUTMSG 30,<'%s/InitUnit, unit= %lx, task=%lx'>
addq.l #8,sp
ENDC
;------ initialize the unit's message port's list
lea MP_MSGLIST(a3),a0
NEWLIST a0 ;<- IMPORTANT! Lists MUST! have NEWLIST
;work magic on them before use. (AddPort()
;can do this for you)
IFD INTRRUPT
move.l a3,mdu_is+IS_DATA(a3) ; Pass unit addr to interrupt server
ENDC
; Startup the task
lea mdu_tcb(a3),a1
lea Task_Begin(PC),a2
move.l a3,-(sp) ; Preserve UNIT pointer
lea -1,a3 ; generate address error
; if task ever "returns" (we RemTask() it
; to get rid of it...)
CLEAR d0
PUTMSG 30,<'%s/About to add task'>
LINKSYS AddTask,md_SysLib(a6)
move.l (sp)+,a3 ; restore UNIT pointer
;------ mark us as ready to go
move.l d2,d0 ; unit number
lsl.l #2,d0
move.l a3,md_Units(a6,d0.l) ; set unit table
PUTMSG 30,<'%s/InitUnit: ok'>
InitUnit_End:
movem.l (sp)+,d2-d4/a2
rts
;---------------------------------------------------------------------------
FreeUnit: ; ( a3:unitptr, a6:deviceptr )
move.l a3,a1
move.l #MyDevUnit_Sizeof,d0
LINKSYS FreeMem,md_SysLib(a6)
rts
;---------------------------------------------------------------------------
ExpungeUnit: ; ( a3:unitptr, a6:deviceptr )
PUTMSG 10,<'%s/ExpungeUnit: called'>
move.l d2,-(sp)
;
; If you can expunge you unit, and each unit has it's own interrupts,
; you must remember to remove its interrupt server
;
IFD INTRRUPT
lea.l mdu_is(a3),a1 ; Point to interrupt structure
moveq #INTB_PORTS,d0 ; Portia interrupt bit 3
LINKSYS RemIntServer,md_SysLib(a6) ;Now remove the interrupt server
ENDC
;------ get rid of the unit's task. We know this is safe
;------ because the unit has an open count of zero, so it
;------ is 'guaranteed' not in use.
lea mdu_tcb(a3),a1
LINKSYS RemTask,md_SysLib(a6)
;------ save the unit number
CLEAR d2
move.b mdu_UnitNum(a3),d2
;------ free the unit structure.
bsr FreeUnit
;------ clear out the unit vector in the device
lsl.l #2,d2
clr.l md_Units(a6,d2.l)
move.l (sp)+,d2
rts
*****************************************************************************
;
; here begins the device functions
;
;----------------------------------------------------------------------------
; cmdtable is used to look up the address of a routine that will
; implement the device command.
;
; NOTE: the "extended" commands (ETD_READ/ETD_WRITE) have bit 15 set!
; We deliberately refuse to operate on such commands. However a driver
; that supports removable media may want to implement this. One
; open issue is the handling of the "seclabel" area. It is probably
; best to reject any command with a non-null "seclabel" pointer.
;
cmdtable:
DC.L Invalid ;$00000001 ;0 CMD_INVALID
DC.L MyReset ;$00000002 ;1 CMD_RESET
DC.L RdWrt ;$00000004 ;2 CMD_READ (\/common)
DC.L RdWrt ;$00000008 ;3 CMD_WRITE (/\common) ETD_
DC.L Update ;$00000010 ;4 CMD_UPDATE (NO-OP) ETD_
DC.L Clear ;$00000020 ;5 CMD_CLEAR (NO-OP) ETD_
DC.L MyStop ;$00000040 ;6 CMD_STOP ETD_
DC.L Start ;$00000080 ;7 CMD_START
DC.L Flush ;$00000100 ;8 CMD_FLUSH
DC.L Motor ;$00000200 ;9 TD_MOTOR (NO-OP) ETD_
DC.L Seek ;$00000400 ;A TD_SEEK (NO-OP) ETD_
DC.L RdWrt ;$00000800 ;B TD_FORMAT (Same as write)
DC.L MyRemove ;$00001000 ;C TD_REMOVE (NO-OP)
DC.L ChangeNum ;$00002000 ;D TD_CHANGENUM (returns 0)
DC.L ChangeState ;$00004000 ;E TD_CHANGESTATE (returns 0)
DC.L ProtStatus ;$00008000 ;F TD_PROTSTATUS (returns 0)
DC.L RawRead ;$00010000 ;10 TD_RAWREAD (INVALID)
DC.L RawWrite ;$00020000 ;11 TD_RAWWRITE (INVALID)
DC.L GetDriveType ;$00040000 ;12 TD_GETDRIVETYPE (Returns 1)
DC.L GetNumTracks ;$00080000 ;13 TD_GETNUMTRACKS (Returns NUMTRKS)
DC.L AddChangeInt ;$00100000 ;14 TD_ADDCHANGEINT (NO-OP)
DC.L RemChangeInt ;$00200000 ;15 TD_REMCHANGEINT (NO-OP)
cmdtable_end:
; this define is used to tell which commands should be handled
; immediately (on the caller's schedule).
;
; The immediate commands are Invalid, Reset, Stop, Start, Flush
;
; Note that this method limits you to just 32 device specific commands,
; which may not be enough.
;IMMEDIATES EQU %00000000000000000000000111000011
;; --------========--------========
;; FEDCBA9876543210FEDCBA9876543210
;;An alternate version. All commands that are trivially short
;;and %100 reentrant are included. This way you won't get the
;;task switch overhead for these commands.
;;
IMMEDIATES EQU %11111111111111111111011111110011
; --------========--------========
; FEDCBA9876543210FEDCBA9876543210
IFD INTRRUPT ; if using interrupts,
; These commands can NEVER be done "immediately" if using interrupts,
; since they would "wait" for the interrupt forever!
; Read, Write, Format
NEVERIMMED EQU $0000080C
ENDC
;--------------------------------
; BeginIO starts all incoming io. The IO is either queued up for the
; unit task or processed immediately.
;
;
; BeginIO often is given the responsibility of making devices single
; threaded... so two tasks sending commands at the same time don't cause
; a problem. Once this has been done, the command is dispatched via
; PerformIO.
;
; There are many ways to do the threading. This example uses the
; UNITB_ACTIVE bit. Be sure this is good enough for your device before
; using! Any method is ok. If immediate access can not be obtained, the
; request is queued for later processing.
;
; Some IO requests do not need single threading, these can be performed
; immediatley.
;
; IMPORTANT:
; The exec WaitIO() function uses the IORequest node type (LN_TYPE)
; as a flag. If set to NT_MESSAGE, it assumes the request is
; still pending and will wait. If set to NT_REPLYMSG, it assumes the
; request is finished. It's the responsibility of the device driver
; to set the node type to NT_MESSAGE before returning to the user.
;
BeginIO: ; ( iob: a1, device:a6 )
IFGE INFO_LEVEL-1
bchg.b #1,$bfe001 ;Blink the power LED
ENDC
IFGE INFO_LEVEL-3
clr.l -(sp)
move.w IO_COMMAND(a1),2(sp) ;Get entire word
PUTMSG 3,<'%s/BeginIO -- $%lx'>
addq.l #4,sp
ENDC
movem.l d1/a0/a3,-(sp)
move.b #NT_MESSAGE,LN_TYPE(a1) ;So WaitIO() is guaranteed to work
move.l IO_UNIT(a1),a3 ;bookkeeping -> what unit to play with
move.w IO_COMMAND(a1),d0
;Do a range check & make sure ETD_XXX type requests are rejected
cmp.w #MYDEV_END,d0 ;Compare all 16 bits
bcc BeginIO_NoCmd ;no, reject it. (bcc=bhs - unsigned)
;------ process all immediate commands no matter what
move.l #IMMEDIATES,d1
DISABLE a0 ;<-- Ick, nasty stuff, but needed here.
btst.l d0,d1
bne BeginIO_Immediate
IFD INTRRUPT ; if using interrupts,
;------ queue all NEVERIMMED commands no matter what
move.w #NEVERIMMED,d1
btst d0,d1
bne.s BeginIO_QueueMsg
ENDC
;------ see if the unit is STOPPED. If so, queue the msg.
btst #MDUB_STOPPED,UNIT_FLAGS(a3)
bne BeginIO_QueueMsg
;------ This is not an immediate command. See if the device is
;------ busy. If the device is not, do the command on the
;------ user schedule. Else fire up the task.
;------ This type of arbitration is not really needed for a ram
;------ disk, but is essential for a device to reliably work
;------ with shared hardware
;------
;------ When the lines below are ";" commented out, the task gets
;------ a better workout. When the lines are active, the calling
;------ process is usually used for the operation.
;------
;------ REMEMBER:::: Never Wait() on the user's schedule in BeginIO()!
;------ The only exception is when the user has indicated it is ok
;------ by setting the "quick" bit. Since this device copies from
;------ ram that never needs to be waited for, this subtlely may not
;------ be clear.
;------
bset #UNITB_ACTIVE,UNIT_FLAGS(a3) ;<---- comment out these
beq.s BeginIO_Immediate ;<---- lines to test task.
;------ we need to queue the device. mark us as needing
;------ task attention. Clear the quick flag
BeginIO_QueueMsg:
bset #UNITB_INTASK,UNIT_FLAGS(a3)
bclr #IOB_QUICK,IO_FLAGS(a1) ;We did NOT complete this quickly
ENABLE a0
IFGE INFO_LEVEL-250
move.l a1,-(sp)
move.l a3,-(sp)
PUTMSG 250,<'%s/PutMsg: Port=%lx Message=%lx'>
addq.l #8,sp
ENDC
move.l a3,a0
LINKSYS PutMsg,md_SysLib(a6) ;Port=a0, Message=a1
bra.s BeginIO_End
;----- return to caller before completing
;------ Do it on the schedule of the calling process
;------
BeginIO_Immediate:
ENABLE a0
bsr.s PerformIO
BeginIO_End:
PUTMSG 200,<'%s/BeginIO_End'>
movem.l (sp)+,d1/a0/a3
rts
BeginIO_NoCmd:
move.b #IOERR_NOCMD,IO_ERROR(a1)
bra.s BeginIO_End
;
; PerformIO actually dispatches an io request. It might be called from
; the task, or directly from BeginIO (thus on the callers's schedule)
;
; It expects a3 to already
; have the unit pointer in it. a6 has the device pointer (as always).
; a1 has the io request. Bounds checking has already been done on
; the I/O Request.
;
PerformIO: ; ( iob:a1, unitptr:a3, devptr:a6 )
IFGE INFO_LEVEL-150
clr.l -(sp)
move.w IO_COMMAND(a1),2(sp) ;Get entire word
PUTMSG 150,<'%s/PerformIO -- $%lx'>
addq.l #4,sp
ENDC
moveq #0,d0
move.b d0,IO_ERROR(A1) ; No error so far
move.b IO_COMMAND+1(a1),d0 ;Look only at low byte
lsl.w #2,d0 ; Multiply by 4 to get table offset
lea.l cmdtable(pc),a0
move.l 0(a0,d0.w),a0
jmp (a0) ;iob:a1 unit:a3 devprt:a6
;
; TermIO sends the IO request back to the user. It knows not to mark
; the device as inactive if this was an immediate request or if the
; request was started from the server task.
;
TermIO: ; ( iob:a1, unitptr:a3, devptr:a6 )
PUTMSG 160,<'%s/TermIO'>
move.w IO_COMMAND(a1),d0
move.w #IMMEDIATES,d1
btst d0,d1
bne.s TermIO_Immediate ;IO was immediate, don't do task stuff...
;------ we may need to turn the active bit off.
btst #UNITB_INTASK,UNIT_FLAGS(a3)
bne.s TermIO_Immediate ;IO was came from task, don't clear ACTIVE...
;------ the task does not have more work to do
bclr #UNITB_ACTIVE,UNIT_FLAGS(a3)
TermIO_Immediate:
;------ if the quick bit is still set then we don't need to reply
;------ msg -- just return to the user.
btst #IOB_QUICK,IO_FLAGS(a1)
bne.s TermIO_End
LINKSYS ReplyMsg,md_SysLib(a6) ;a1-message
;(ReplyMsg sets the LN_TYPE to NT_REPLYMSG)
TermIO_End:
rts
*****************************************************************************
;
; Here begins the functions that implement the device commands
; all functions are called with:
; a1 -- a pointer to the io request block
; a3 -- a pointer to the unit
; a6 -- a pointer to the device
;
; Commands that conflict with 68000 instructions have a "My" prepended
; to them.
;----------------------------------------------------------------------
;We can't AbortIO anything, so don't touch the IORequest!
;
;AbortIO() is a REQUEST to "hurry up" processing of an IORequest.
;If the IORequest was already complete, nothing happens (if an IORequest
;is quick or LN_TYPE=NT_REPLYMSG, the IORequest is complete).
;The message must be replied with ReplyMsg(), as normal.
;
AbortIO: ; ( iob: a1, device:a6 )
moveq #IOERR_NOCMD,d0 ;return "AbortIO() request failed"
rts
RawRead: ; 10 Not supported (INVALID)
RawWrite: ; 11 Not supported (INVALID)
Invalid:
move.b #IOERR_NOCMD,IO_ERROR(a1)
bra.s TermIO
;
; Update and Clear are internal buffering commands. Update forces all
; io out to its final resting spot, and does not return until this is
; totally done. Since this is automatic in a ramdisk, we simply return "Ok".
;
; Clear invalidates all internal buffers. Since this device
; has no internal buffers, these commands do not apply.
;
Update:
Clear:
MyReset: ;Do nothing (nothing reasonable to do)
AddChangeInt: ;Do nothing
RemChangeInt: ;Do nothing
MyRemove: ;Do nothing
Seek: ;Do nothing
Motor: ;Do nothing
ChangeNum: ;Return zero (changecount =0)
ChangeState: ;Zero indicates disk inserted
ProtStatus: ;Zero indicates unprotected
clr.l IO_ACTUAL(a1)
bra.s TermIO
GetDriveType: ;make it look like 3.5" (90mm) drive
moveq #DRIVE3_5,d0
move.l d0,IO_ACTUAL(a1)
bra.s TermIO
GetNumTracks:
move.l #RAMSIZE/BYTESPERTRACK,IO_ACTUAL(a1) ;Number of tracks
bra.s TermIO
;
; Foo and Bar are two device specific commands that are provided just
; to show you how commands are added. They currently return that
; no work was done.
;
Foo:
Bar:
clr.l IO_ACTUAL(a1)
bra TermIO
;---------------------------------------------------------------------------
; This device is designed so that no combination of bad
; inputs can ever cause the device driver to crash.
;---------------------------------------------------------------------------
RdWrt:
IFGE INFO_LEVEL-200
move.l IO_DATA(a1),-(sp)
move.l IO_OFFSET(a1),-(sp)
move.l IO_LENGTH(a1),-(sp)
PUTMSG 200,<'%s/RdWrt len %ld offset %ld data $%lx'>
addq.l #8,sp
addq.l #4,sp
ENDC
movem.l a2/a3,-(sp)
move.l a1,a2 ;Copy iob
move.l IO_UNIT(a2),a3 ;Get unit pointer
* check operation for legality
btst.b #0,IO_DATA+3(a2) ;check if user's pointer is ODD
bne.s IO_LenErr ;bad...
;[D0=offset]
move.l IO_OFFSET(a2),d0
move.l d0,d1
and.l #SECTOR-1,d1 ;Bad sector boundary or alignment?
bne.s IO_LenErr ;bad...
;[D0=offset]
* check for IO within disc range
;[D0=offset]
add.l IO_LENGTH(a2),d0 ;Add length to offset
bcs.s IO_LenErr ;overflow... (important test)
cmp.l #RAMSIZE,d0 ;Last byte is highest acceptable total
bhi.s IO_LenErr ;bad... (unsigned compare)
and.l #SECTOR-1,d0 ;Even sector boundary?
bne.s IO_LenErr ;bad...
* We've gotten this far, it must be a valid request.
IFD INTRRUPT
move.l mdu_SigMask(a3),d0 ; Get signals to wait for
LINKSYS Wait,md_SysLib(a6) ; Wait for interrupt before proceeding
ENDC
lea.l mdu_RAM(a3),a0 ; Point to RAMDISK "sector" for I/O
add.l IO_OFFSET(a2),a0 ; Add offset to ram base
move.l IO_LENGTH(a2),d0
move.l d0,IO_ACTUAL(a2) ; Indicate we've moved all bytes
beq.s RdWrt_end ;---deal with zero length I/O
move.l IO_DATA(a2),a1 ; Point to data buffer
;
;A0=ramdisk index
;A1=user buffer
;D0=length
;
cmp.b #CMD_READ,IO_COMMAND+1(a2) ; Decide on direction
BEQ.S CopyTheBlock
EXG A0,A1 ; For Write and Format, swap source & dest
CopyTheBlock:
LINKSYS CopyMemQuick,md_SysLib(a6) ;A0=source A1=dest D0=size
;CopyMemQuick is very fast
RdWrt_end:
move.l a2,a1
movem.l (sp)+,a2/a3
bra TermIO ;END
IO_LenErr:
PUTMSG 10,<'bad length'>
move.b #IOERR_BADLENGTH,IO_ERROR(a2)
IO_End:
clr.l IO_ACTUAL(a2) ;Initially, no data moved
bra.s RdWrt_end
;
; the Stop command stop all future io requests from being
; processed until a Start command is received. The Stop
; command is NOT stackable: e.g. no matter how many stops
; have been issued, it only takes one Start to restart
; processing.
;
;Stop is rather silly for a ramdisk
MyStop:
PUTMSG 30,<'%s/MyStop: called'>
bset #MDUB_STOPPED,UNIT_FLAGS(a3)
bra TermIO
Start:
PUTMSG 30,<'%s/Start: called'>
bsr.s InternalStart
bra TermIO
;[A3=unit A6=device]
InternalStart:
move.l a1,-(sp)
;------ turn processing back on
bclr #MDUB_STOPPED,UNIT_FLAGS(a3)
;------ kick the task to start it moving
move.b MP_SIGBIT(a3),d1
CLEAR d0
bset d1,d0 ;prepared signal mask
move.l MP_SIGTASK(a3),a1 ;:FIXED:marco-task to signal
LINKSYS Signal,md_SysLib(a6) ;:FIXED:marco-a6 not a3
move.l (sp)+,a1
rts
;
; Flush pulls all I/O requests off the queue and sends them back.
; We must be careful not to destroy work in progress, and also
; that we do not let some io requests slip by.
;
; Some funny magic goes on with the STOPPED bit in here. Stop is
; defined as not being reentrant. We therefore save the old state
; of the bit and then restore it later. This keeps us from
; needing to DISABLE in flush. It also fails miserably if someone
; does a start in the middle of a flush. (A semaphore might help...)
;
Flush:
PUTMSG 30,<'%s/Flush: called'>
movem.l d2/a1/a6,-(sp)
move.l md_SysLib(a6),a6
bset #MDUB_STOPPED,UNIT_FLAGS(a3)
sne d2
Flush_Loop:
move.l a3,a0
CALLSYS GetMsg ;Steal messages from task's port
tst.l d0
beq.s Flush_End
move.l d0,a1
move.b #IOERR_ABORTED,IO_ERROR(a1)
CALLSYS ReplyMsg
bra.s Flush_Loop
Flush_End:
move.l d2,d0
movem.l (sp)+,d2/a1/a6
tst.b d0
beq.s 1$
bsr InternalStart
1$:
bra TermIO
*****************************************************************************
;
; Here begins the task related routines
;
; A Task is provided so that queued requests may be processed at
; a later time. This is not very justifiable for a ram disk, but
; is very useful for "real" hardware devices. Take care with
; your arbitration of shared hardware with all the multitasking
; programs that might call you at once.
;
; Register Usage
; ==============
; a3 -- unit pointer
; a6 -- syslib pointer
; a5 -- device pointer
; a4 -- task (NOT process) pointer
; d7 -- wait mask
;----------------------------------------------------------------------
; some dos magic, useful for Processes (not us). A process is started at
; the first executable address after a segment list. We hand craft a
; segment list here. See the the DOS technical reference if you really
; need to know more about this.
; The next instruction after the segment list is the first executable address
cnop 0,4 ; long word align
DC.L 16 ; segment length -- any number will do (this is 4
; bytes back from the segment pointer)
myproc_seglist:
DC.L 0 ; pointer to next segment
Task_Begin:
PUTMSG 35,<'%s/Task_Begin'>
move.l ABSEXECBASE,a6
;------ Grab the argument passed down from our parent
move.l 4(sp),a3 ; Unit pointer
move.l mdu_Device(a3),a5 ; Point to device structure
IFD INTRRUPT
;------ Allocate a signal for "I/O Complete" interrupts
moveq #-1,d0 ; -1 is any signal at all
CALLSYS AllocSignal
move.b d0,mdu_SigBit(A3) ; Save in unit structure
moveq #0,d7 ; Convert bit number signal mask
bset d0,d7
move.l d7,mdu_SigMask(A3) ; Save in unit structure
lea.l mdu_is(a3),a1 ; Point to interrupt structure
moveq #INTB_PORTS,d0 ; Portia interrupt bit 3
CALLSYS AddIntServer ; Now install the server
move.l md_Base(a5),a0 ; Get board base address
* bset.b #INTENABLE,INTCTRL2(a0) ; Enable interrupts
ENDC
;------ Allocate a signal
moveq #-1,d0 ; -1 is any signal at all
CALLSYS AllocSignal
move.b d0,MP_SIGBIT(a3)
move.b #PA_SIGNAL,MP_FLAGS(a3) ;Make message port "live"
;------ change the bit number into a mask, and save in d7
moveq #0,d7 ;Clear D7
bset d0,d7
IFGE INFO_LEVEL-40
move.l $114(a6),-(sp)
move.l a5,-(sp)
move.l a3,-(sp)
move.l d0,-(sp)
PUTMSG 40,<'%s/Signal=%ld, Unit=%lx Device=%lx Task=%lx'>
add.l #4*4,sp
ENDC
bra.s Task_StartHere
; OK, kids, we are done with initialization. We now can start the main loop
; of the driver. It goes like this. Because we had the port marked
; PA_IGNORE for a while (in InitUnit) we jump to the getmsg code on entry.
; (The first message will probably be posted BEFORE our task gets a chance
; to run)
;------ wait for a message
;------ lock the device
;------ get a message. If no message, unlock device and loop
;------ dispatch the message
;------ loop back to get a message
;------ no more messages. back ourselves out.
Task_Unlock:
and.b #$ff&(~(UNITF_ACTIVE!UNITF_INTASK)),UNIT_FLAGS(a3)
;------ main loop: wait for a new message
Task_MainLoop:
PUTMSG 75,<'%s/++Sleep'>
move.l d7,d0
CALLSYS Wait
IFGE INFO_LEVEL-5
bchg.b #1,$bfe001 ;Blink the power LED
ENDC
Task_StartHere:
PUTMSG 75,<'%s/++Wakeup'>
;------ see if we are stopped
btst #MDUB_STOPPED,UNIT_FLAGS(a3)
bne.s Task_MainLoop ; device is stopped, ignore messages
;------ lock the device
bset #UNITB_ACTIVE,UNIT_FLAGS(a3)
bne Task_MainLoop ; device in use (immediate command?)
;------ get the next request
Task_NextMessage:
move.l a3,a0
CALLSYS GetMsg
PUTMSG 1,<'%s/GotMsg'>
tst.l d0
beq Task_Unlock ; no message?
;------ do this request
move.l d0,a1
exg a5,a6 ; put device ptr in right place
bsr PerformIO
exg a5,a6 ; get syslib back in a6
bra.s Task_NextMessage
*****************************************************************************
;
; Here is a dummy interrupt handler, with some crucial components commented
; out. If the IFD INTRRUPT is enabled, this code will cause the device to
; wait for a level two interrupt before it will process each request
; (pressing RETURN on the keyboard will do it). This code is normally
; disabled, and must fake or omit certain operations since there isn't
; really any hardware for this driver. Similar code has been used
; successfully in other, "REAL" device drivers.
;
IFD INTRRUPT
; A1 should be pointing to the unit structure upon entry! (IS_DATA)
myintr:
* move.l md_Base(a0),a0 ; point to board base address
* btst.b #IAMPULLING,INTCTRL1(a0);See if I'm interrupting
* beq.s myexnm ; if not set, exit, not mine
* move.b #0,INTACK(a0) ; toggle controller's int2 bit
; ------ signal the task that an interrupt has occurred
move.l mdu_Device(a1),a0 ; Get device pointer
move.l mdu_SigMask(a1),d0
lea.l mdu_tcb(a1),a1
move.l md_SysLib(a0),a6 ; Get pointer to system
CALLSYS Signal
; now clear the zero condition code so that
; the interrupt handler doesn't call the next
; interrupt server.
;
* moveq #1,d0 clear zero flag
* bra.s myexit now exit
;
; this exit point sets the zero condition code
; so the interrupt handler will try the next server
; in the interrupt chain
;
myexnm moveq #0,d0 set zero condition code
;
myexit rts
ENDC
*****************************************************************************
mdu_Init:
; ------ Initialize the device
INITBYTE MP_FLAGS,PA_IGNORE ;Unit starts with a message port
INITBYTE LN_TYPE,NT_MSGPORT ;
INITLONG LN_NAME,myName ;
INITLONG mdu_tcb+LN_NAME,myName
INITBYTE mdu_tcb+LN_TYPE,NT_TASK
INITBYTE mdu_tcb+LN_PRI,5
IFD INTRRUPT
INITBYTE mdu_is+LN_PRI,4 ; Int priority 4
INITLONG mdu_is+IS_CODE,myintr ; Interrupt routine addr
INITLONG mdu_is+LN_NAME,myName
ENDC
DC.W 0
IFNE AUTOMOUNT
mdn_Init:
* ;------ Initialize packet for MakeDosNode
INITLONG mdn_execName,myName ; Address of driver name
INITLONG mdn_tableSize,12 ; # long words in AmigaDOS env.
INITLONG mdn_dName,$524d0000 ; Store 'RM' in name
INITLONG mdn_sizeBlock,SECTOR/4 ; # longwords in a block
INITLONG mdn_numHeads,1 ; RAM disk has only one "head"
INITLONG mdn_secsPerBlk,1 ; secs/logical block, must = "1"
INITLONG mdn_blkTrack,SECTORSPER ; secs/track (must be reasonable)
INITLONG mdn_resBlks,1 ; reserved blocks, MUST > 0!
INITLONG mdn_upperCyl,(RAMSIZE/BYTESPERTRACK)-1 ; upper cylinder
INITLONG mdn_numBuffers,1 ; # AmigaDOS buffers to start
DC.W 0
ENDC
;----------------------------------------------------------------------
; EndCode is a marker that shows the end of your code. Make sure it does not
; span hunks, and is not before the rom tag! It is ok to put it right after
; the rom tag -- that way you are always safe. I put it here because it
; happens to be the "right" thing to do, and I know that it is safe in this
; case (this program has only a single code hunk).
;----------------------------------------------------------------------
EndCode: END
