************************************************************************* * * devent.a -- device startup code. * * Based on ramdev.device.asm * 12/16/94 Svend Daugaard Pedersen * * Bugs: If RTF_AUTOINIT fails, library base still left in memory. * ************************************************************************* SECTION firstsection include "exec/types.i" include "exec/memory.i" include "exec/devices.i" include "exec/initializers.i" include "exec/resident.i" include "exec/io.i" include "exec/errors.i" include "exec/tasks.i" include "exec/execbase.i" include "libraries/dosextens.i" ; include "asmsupp.i" ;standard asmsupp.i, same as used for library CALLSYS MACRO ; call a library via A6 without using _LVO JSR _LVO\1(A6) ENDM XLIB MACRO ; define a library reference without the _LVO XREF _LVO\1 ENDM STRUCTURE DEVBASE,LIB_SIZE UBYTE db_Flags UBYTE db_Pad1 ;now longword aligned ULONG db_SegList LABEL DEVBASE_Sizeof MEMFLAGS EQU MEMF_CLEAR+MEMF_PUBLIC ABSEXECBASE equ 4 ;Absolute location of the pointer to exec.library base XDEF _TaskStartup ; small code to startup a new task XDEF __XCEXIT ; exit(code) is standard way to leave C. ;------ debuggers to have them globally visible XREF _DevInit XREF _DevOpen XREF _DevClose XREF _DevExpunge XREF _DevBeginIO XREF _DevAbortIO XREF _NewTask XREF _DevIdString XREF _DevName XREF _LinkerDB XREF _RESLEN XREF _RESBASE XREF _NEWDATAL XREF ___fpinit ; initialize floating point XREF ___fpterm ; terminate floating point ;Pull these _LVOs in from amiga.lib XLIB OpenLibrary XLIB CloseLibrary XLIB AllocMem XLIB FreeMem XLIB Remove XLIB AddPort XLIB PutMsg XLIB ReplyMsg XLIB GetMsg XLIB Wait XLIB WaitPort XLIB SetTaskPri XLIB Forbid XLIB SetSignal ;----------------------------------------------------------------------- ; 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). section text,code 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 _DevName ; APTR RT_NAME (exec name) DC.L _DevIdString ; APTR RT_IDSTRING (text string) DC.L Init ; APTR RT_INIT ; LABEL RT_SIZE ; a major version number. VERSION: EQU 37 ;DevName: DC.B "fysik.device",0 ;DevIdString: DC.B "fysikdevice",0 ; 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 ; 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 DEVBASE_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 ;------ 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,_DevName INITBYTE LIB_FLAGS,LIBF_SUMUSED!LIBF_CHANGED INITWORD LIB_VERSION,VERSION INITWORD LIB_REVISION,REVISION INITLONG LIB_IDSTRING,_DevIdString 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. ; ; Routine calls C-routine ; ; struct Library *DevInit(struct Library *libbase) ; ; This call is single-threaded by exec; please read the description for ; "Open" below. ; ; Register Usage ; ============== ; a5 -- device pointer ; a6 -- Exec base ;---------------------------------------------------------------------- initRoutine: ;------ get the device pointer into a convenient A register MOVEM.L D1/A0-A1/A4-A5,-(A7) ; Preserve ALL modified registers MOVE.L D0,A5 ;------ save pointer to our loaded code (the SegList) MOVE.L A0,db_SegList(A5) BSR SetUp ; Set up new data area etc. TST.L D0 BEQ.S InitRet MOVE.L A4,dbase ; Save data base for future use ;--------------------------------------------- ; Call device init routine MOVE.L A5,-(A7) BSR _DevInit ADDQ.L #4,A7 InitRet: MOVEM.L (A7)+,D1/A0-A1/A4-A5 RTS dbase: dc.l 0 ;---------------------------------------------------------------------- ; ; 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 will set up A4 and call C-Open routine: ; ; int DevOpen(struct Library *libbase,long unit,struct IORequest *ior,long flags) ; ; and then set the IO_ERROR field to the return value 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. ; ; Called with ; A6 = device base (struct Library) ; A1 = IORequest ; D1 = flags ; D0 = unit number ; Open: ADDQ.W #1,LIB_OPENCNT(A6) ;Fake an opener for duration of call <|> MOVEM.L A2/A4,-(A7) MOVE.L A1,A2 ; save the IORequest MOVE.L dbase(PC),A4 ; Get C-code data base MOVE.L D1,-(A7) MOVE.L A1,-(A7) MOVE.L D0,-(A7) MOVE.L A6,-(A7) BSR _DevOpen LEA 16(A7),A7 TST.L D0 BEQ.S OpenOk MOVEQ.L #-1,D1 MOVE.L D1,IO_DEVICE(A2) ; IMPORTANT: trash IO_DEVICE on open failure SUBQ.W #1,LIB_OPENCNT(A6) ; End of expunge protection <|> BRA.S OpenEnd OpenOk: ;------ prevent delayed expunges BCLR #LIBB_DELEXP,db_Flags(A6) MOVE.B #NT_REPLYMSG,LN_TYPE(A2) ;IMPORTANT: Mark IORequest as "complete" OpenEnd: MOVE.B D0,IO_ERROR(A2) MOVEM.L (A7)+,A2/A4 RTS ;---------------------------------------------------------------------------- ; 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. ; ; Open will set up A4 and call C-Open routine: ; ; void DevClose(struct Library *libbase,struct IORequest *ior) ; ; Called with ; A6 = device base (struct Library) ; A1 = IORequest ; Close: MOVEM.L D1/A2-A4,-(A7) MOVE.L A1,A2 ; save the IORequest MOVE.L dbase(PC),A4 ; Get C-code data base MOVE.L A1,-(A7) MOVE.L A6,-(A7) BSR _DevClose LEA 8(A7),A7 ;------ 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!! MOVEQ.L #0,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,db_Flags(A6) BEQ.S Close_End ;------ do the expunge BSR Expunge Close_End: MOVEM.L (A7)+,D1/A2-A4 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. ; ; If ready to be expunged calls C-routine: ; ; BOOL DevExpunge(struct MyLibrary *libbase) ; ; Registers at call ; A6 - library base (scratch) ; D0-D1/A0-A1 - scratch ; Expunge: MOVEM.L D1/D2/A4-A6,-(A7) ; Save ALL modified registers MOVE.L A6,A5 MOVE.L ABSEXECBASE.W,A6 ;------ see if anyone has us open TST.W LIB_OPENCNT(A5) BEQ.S CleanUp ;------ it is still open. set the delayed expunge flag BSET #LIBB_DELEXP,db_Flags(A5) MOVEQ.L #0,D0 BRA.S Expunge_End CleanUp: MOVE.L dbase(PC),A4 ; Get C-code data base MOVE.L A5,-(A7) BSR _DevExpunge ADDQ.L #4,A7 EXT.L D0 BEQ.S Expunge_End ; Don't expunge ! ;------ go ahead and get rid of us. BSR FreeData ; Free data area, close DOS, ; clean up any floating point etc. MOVE.L db_SegList(A5),D2 ; Store our seglist in D2 ;------ unlink from device list MOVE.L A5,A1 CALLSYS Remove ; Remove first (before FreeMem) ;------ free our memory (must calculate from LIB_POSSIZE & LIB_NEGSIZE) MOVE.L A5,A1 ; Devicebase MOVEQ.L #0,D0 MOVE.W LIB_NEGSIZE(A5),d0 SUB.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 (A7)+,D1/D2/A4-A6 RTS ;------- Null --------------------------------------------------------------- ; Null: MOVEQ.L #0,D0 ;The "Null" function MUST return NULL. RTS ;-------------------------------- ; 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. ; ; Routine calls C-coded function: ; ; void DevBeginIO(struct MyLibrary *libbase,struct IORequest *ior) ; ; Registers at entrance ; A1 = IORequest ; A6 = Device ; BeginIO: MOVE.L A4,-(A7) MOVE.L dbase(PC),A4 ; Get C-code data base MOVE.L A1,-(A7) MOVE.L A6,-(A7) BSR _DevBeginIO LEA 8(A7),A7 MOVE.L (A7)+,A4 RTS ; 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. ; ; Routine calls C-coded function: ; ; void DevAbortIO(struct MyLibrary *libbase,struct IORequest *ior) ; ; Registers at entrance ; A1 = IORequest ; A6 = Device ; AbortIO: MOVE.L A4,-(A7) MOVE.L dbase(PC),A4 ; Get C-code data base MOVE.L A1,-(A7) MOVE.L A6,-(A7) BSR _DevAbortIO LEA 8(A7),A7 MOVE.L (A7)+,A4 RTS ; some dos magic, useful for Processes. 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) proc_seglist: DC.L 0 ; pointer to next segment _TaskStartup: MOVEM.L D1-D6/A0-A6,-(A7) ; First save all registers ;-------------------------------------------------------------- ; Then get startup message ; MOVE.L ABSEXECBASE.W,A6 MOVE.L ThisTask(A6),A3 LEA pr_MsgPort(A3),A0 ; Point to message port CALLSYS WaitPort LEA pr_MsgPort(A3),A0 CALLSYS GetMsg MOVE.L D0,A2 ; Startup message to A2 BSR.S SetUp ; Set up new data area etc. TST.L D0 BEQ.S StartupFailed MOVE.L A7,StackSave(A4) ; Save stack pointer MOVE.L A2,A1 ; Startup message to A1 CALLSYS ReplyMsg ; Reply startup message: Ok until now ;-------------------------------------------------------------- ; Parameters on stack and call start of new task ; MOVE.L MN_SIZE+8(A2),-(A7) ; device unit number MOVE.L MN_SIZE+4(A2),-(A7) ; device name MOVE.L MN_SIZE(A2),-(A7) ; pointer to structure Unit BSR _NewTask ; Execute main program __XCEXIT: MOVE.L StackSave(A4),A7 ; Set up old stack BSR FreeData BRA.S exit ;-------------------------------------------------------------- ; Process startup failed - not enough memory ; StartupFailed: MOVE.L A2,A1 ; Startup message to A1 MOVE.L D0,MN_SIZE(A1) ; Signal error CALLSYS ReplyMsg ;----------------------------------------------------------------- ; Get terminating message ; exit: MOVE.L ABSEXECBASE.W,A6 MOVE.L ThisTask(A6),A3 LEA pr_MsgPort(A3),A0 ; Point to message port MOVE.L A0,-(A7) CALLSYS WaitPort MOVE.L (A7)+,A0 CALLSYS GetMsg MOVE.L D0,A2 ; Message to A2 CALLSYS Forbid ; Make a safe exit MOVE.L A2,A1 CALLSYS ReplyMsg MOVEM.L (A7)+,D1-D6/A0-A6 ; Get back saved registers MOVEQ.L #0,D0 RTS ; ..and return ;------------------------------------------------------------------------ ;------------------------------------------------------------------------ ; ; Set up new data area, open DOS and initialize fp ; ; At call: - ; At return: D0 <>0, if ok and D0=0, if fail ; A4 = data base for new initialized data area (or zero) ; ; Regs used: D0-D1/A0-A1/A4 ; SetUp: LEA _LinkerDB,A4 ; Load base register MOVEM.L D2/A2/A6,-(A7) MOVE.L #_RESLEN+4,D0 ; Get length of data area MOVE.L #MEMFLAGS,D1 MOVE.L ABSEXECBASE.W,A6 CALLSYS AllocMem ; Allocate memory TST.L D0 BEQ.S SetUpRet MOVE.L D0,A0 MOVE.L #_RESLEN+4,D0 ; Get length of data area MOVE.L D0,(A0)+ MOVE.L A0,A1 MOVE.L A0,A2 MOVE.L #_NEWDATAL,D0 ; Length of initialized data SUB.L #_RESBASE,A4 ; Point to real start ; Copy initialized data over 1$: MOVE.L (A4)+,(A0)+ SUBQ.L #1,D0 BNE 1$ ; A4 now points at number of relocs MOVE.L (A4)+,D0 ; Get the number BEQ.S NoReloc ; Branch if no relocs 2$: MOVE.L A1,A0 ; A0 = new data start ADD.L (A4)+,A0 ; A0 has add of reloc ADD.L (A0),A2 MOVE.L A2,(A0) MOVE.L A1,A2 ; Restore offset SUBQ.L #1,d0 BNE 2$ ; Continue until all done NoReloc: MOVE.L A1,A4 ; Set up new base register ADD.L #_RESBASE,A4 ADD.L #_RESLEN,D2 ; Number of bytes allocated MOVE.L A6,_SysBase(A4) ; Set ExecBase *------ Set __base for stack checking MOVE.L A7,D0 SUB.L D1,D0 ADD.L #256,D0 ; Safe low bound of stack MOVE.L D0,__base(A4) ; Save for stack checking *----- clear any pending signals MOVEQ #0,d0 MOVE.L #$00003000,d1 CALLSYS SetSignal *------ Open DOS library: LEA DOSName(PC),A1 MOVEQ #0,D0 CALLSYS OpenLibrary MOVE.L D0,_DOSBase(A4) BNE.S SetUpOk BSR.S FreeData1 MOVEQ #0,D0 BRA.S SetUpRet ;--------------------------------------------- ; Initialize floating point and constructors ; SetUpOk: MOVE.L D0,-(A7) JSR ___fpinit(PC) MOVE.L (A7)+,D0 SetUpRet: MOVEM.L (A7)+,D2/A2/A6 RTS ; Free data area ; ; At call: A4 = pointer to data base ; At return: - ; Regs used: D0-D1,A0-A1/A6 ; FreeData: JSR ___fpterm(PC) ; clean up any floating point etc. MOVE.L ABSEXECBASE.W,A6 MOVE.L _DOSBase(A4),A1 CALLSYS CloseLibrary ; Close Dos library FreeData1: MOVE.L A4,A1 SUB.L #_RESBASE,A1 MOVE.L -(A1),D0 MOVE.L ABSEXECBASE.W,A6 CALLSYS FreeMem RTS DOSName dc.b 'dos.library',0 ;---------------------------------------------------------------------- ; 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: equ * csect __MERGED,1,0,0,4 XREF _DOSBase xdef _NULL,_SysBase _SysBase: DC.L 0 __base: DC.L 0 _NULL DC.L 0 StackSave: DC.L 0 END