opt o+,ow- ;Devpac 2.0 options ; Before we go to the main subject, I'll give some special information about ; macros in Devpac 2.0. ; ; It is possible to pass a size (byte, word, long) to macros. This is done ; with \0 (the SIZE parameter). If ".b" or ".w" or ".l" is added just after ; the macro name in the macro call then \0 will result in "b" or "w" or "l". ; When no size is given \0 will default to "w". ; ; If you want to pass a parameter that contains spaces then enclose the ; parameter in the macro call between these brackets: <>. ; ; Now we go to the main event... ; ;--------------------------------------------------------------------------- ; ; Dr. Maybe presents... >>>> GETDRIVE routine <<<< ; ; I would like to talk about a common problem in programs that write to disk ; at low level (i.e. at bitmap level). For example a simple fast-format ; (initialize) function or installing an intro or picture in the first few ; tracks of a disk. ; ; What happens? Mostly the bitmap structure of the disk is changed. In case ; of initializing a new Root and Bitmap block are written, and in case of a ; bootintro the Bitmap block is changed in such a way that a few tracks are ; allocated for the intro. In both cases the information on the disk has ; changed. ; ; But AmigaDOS must be informed about this. Otherwise AmigaDOS will give ; wrong information about the disk. After initializing the disk will still ; be full or not validated. After a bootintro is installed too much free ; disk space will be showed. The only way to update the disk information is ; to eject and insert it. Another danger is when other tasks want to have ; access to the disk, while your program is writing to the tracks! ; ; I hope the problem is clear. The program must reserve the drive for own ; use, without permitting other tasks to have access to it, and afterwards ; the drive must be returned to system. Well, that's not so difficult, you ; might think, lets look it up in the books. I sought and sought, but didn't ; find. And I think most other Amiga programmers have the same problem. Take ; for example "Bootleg" or "Bootgirl" or "Bootem". Only the Workbench Format ; command does drive-handling nicely. You even get a "DF1:BUSY" icon. ; ; So, what's the only thing left to do for an Amiga freak? Right, you ; guessed it, I disassembled the Format command! Here comes the solution. ; ;--------------------------------------------------------------------------- ; ; First find the task that's responsible for giving other tasks access to ; the drive. This is done with the following function from dos.library: ; ; Process_MessagePort = DeviceProc( name ) ; d0 d1 ; ; Here d1 points to the name of the drive (e.g. 'DF1:',0), which is a ; NULL-terminated string. The returned value in d0 is the MessagePort of the ; DOS process that's controlling the drive. A DOS process is just an exec ; task added with a MessagePort (so we can talk with it) and some DOS ; information (like CLI, Filesystem, etc). All programs loaded from CLI or ; Workbench are DOS processes. Lets take a look at ; "include/libraries/dosextens.i": ; ; STRUCTURE Process,0 ; STRUCT pr_Task,TC_SIZE * APTR to exec task ; STRUCT pr_MsgPort,MP_SIZE * This is BPTR address from DOS functions ; WORD pr_Pad * Remaining variables on 4 byte boundaries ; BPTR pr_SegList * Array of seg lists used by this process ; (etc) ;--------------------------------------------------------------------------- ; ; Now we send a StandardPacket to the process. A standard packet is just an ; exec message added with some extras, called DOS packet. These extras ; consist of our ReplyPort (to get messages back) and information about the ; command we would like to give to the process. Lets take a look at ; "include/libraries/dosextens.i": ; ; STRUCTURE StandardPacket,0 ; STRUCT sp_Msg,MN_SIZE * message ; STRUCT sp_Pkt,dp_SIZEOF * DOS packet ; LABEL sp_SIZEOF ; ; STRUCTURE DosPacket,0 ; APTR dp_Link * pointer to EXEC message ; APTR dp_Port * pointer to Reply port for the packet ; * Must be filled in each send. ; LONG dp_Type * See ACTION_... below and ; * 'R' means Read, 'W' means Write to the file system ; LONG dp_Res1 * For file system calls this is the result ; * that would have been returned by the ; * function, e.g. Write ('W') returns actual ; * length written ; LONG dp_Res2 * For file system calls this is what would ; * have been returned by IoErr() ; LONG dp_Arg1 ; (etc) ; ; ACTION_INHIBIT EQU 31 ; (etc) ; ; The most important element here is dp_Type. This element is filled with ; the command we want to give: ACTION_INHIBIT. For drive reservation we make ; dp_Arg1 = 1 and to return the drive to system we make dp_Arg1 = 0. We can ; do many things with packets. Look at the complete include file yourself! ; After setting up the packet properly, we send it to the process port with ; the exec function PutMsg. Then we GetMsg from drive process back and ; Remove the packet and check error in dp_Res1. ; ;--------------------------------------------------------------------------- ; ; Of course you did't understand anything of this bulls..t mambo jambo (I ; kneuw that!), but it works perfectly. Even the "DF0:BUSY" icon appears in ; Workbench!! For full details look at the GetDrive routine below. ; ; GOOD LUCK! ; ; Dr. Maybe ; Postbus 121 ; 6850 AD Huissen ; Holland ; ;--------------------------------------------------------------------------- incdir "ram:include/" ;your include directory include "exec/exec_lib.i" include "exec/memory.i" include "exec/ports.i" include "libraries/dos_lib.i" include "libraries/dosextens.i" CALL MACRO ;library function call jsr _LVO\1(a6) ENDM SECTION main,CODE ;**** Open DOS **** lea _DOSName(pc),a1 moveq #0,d0 CALLEXEC OpenLibrary move.l d0,_DOSBase beq quit ;**** Open RAW Window, so I can talk to you. **** lea rawwindowname(pc),a0 move.l a0,d1 move.l #MODE_OLDFILE,d2 CALLDOS Open move.l d0,rawwindow beq quit ;**** Now get drive for own use. **** lea drivename(pc),a0 moveq #1,d0 bsr GetDrive beq.s ok ;**** check & display error, and quit **** lea not_mounted(pc),a0 cmp.b #218,d0 beq.s prt lea doserror(pc),a0 cmp.b #100,d0 beq.s prt lea drive_in_use(pc),a0 prt bsr print bsr wait_key bra.s quit ok ;**** drive disabled successfully **** lea drive_disabled(pc),a0 bsr print bsr wait_key ;**** return drive to system lea drivename(pc),a0 moveq #0,d0 bsr GetDrive quit ;**** cleanup & exit **** move.l rawwindow(pc),d1 ;close raw window beq.s .q1 CALLDOS Close .q1 move.l _DOSBase(pc),d0 ;close DOS beq.s .q2 move.l d0,a1 CALLEXEC CloseLibrary .q2 moveq #0,d0 rts print ;**** output text in a0 to rawwindow, and wait **** move.l rawwindow(pc),d1 move.l a0,d2 moveq #-1,d3 .loop addq.l #1,d3 tst.b (a0)+ bne.s .loop CALLDOS Write rts wait_key ;**** wait for key in raw window ***** move.l rawwindow(pc),d1 lea press_key(pc),a0 bsr print move.l rawwindow(pc),d1 lea buffer(pc),a0 move.l a0,d2 moveq #1,d3 CALLDOS Read rts GetDrive ;*************************************************************************** ; * ; Drive disable/enable, (C) Dr. Maybe, Huissen 1990 * ; This routine disables a drive from being used by AmigaDOS, for example * ; if you want to format a disk, or install a bootintro on it. * ; In WorkBench this will result in a "BUSY" icon. * ; Afterwards drive must be returned to system. * ; * ; usage: * ; error = GetDrive( drive_name, action ) * ; d0 a0 d0 * ; * ; drive_name = NULL-terminated string to drive name (e.g. 'DF1:',0) * ; action = 1 to get drive for own use * ; 0 to return drive to system * ; * ; error = 0 if OK * ; 103 if not enough memory * ; 218 if drive not mounted * ; 100 if dos error * ; 126 if disable failed * ; * ;*************************************************************************** move.l d0,d2 ;d2 = action move.l a0,a3 ;a3 = drive name ;=========================================================================== ; Allocate memory for StandardPacket structure # ;=========================================================================== moveq #sp_SIZEOF,d0 move.l #MEMF_CLEAR+MEMF_PUBLIC,d1 CALLEXEC AllocMem bne.s .cnt3 moveq #103,d0 rts .cnt3 move.l d0,a2 ;a2 = StandardPacket ;=========================================================================== ; Initialize a StandardPacket to send to process that controls the drive # ;=========================================================================== lea sp_Pkt(a2),a0 move.l a0,sp_Msg+MN+LN_NAME(a2);message node name = DOS packet move.l a2,sp_Pkt+dp_Link(a2) ;pointer to exec message sub.l a1,a1 ;own task (process) CALL FindTask move.l d0,a1 lea pr_MsgPort(a1),a0 ;own task message port is move.l a0,d4 move.l a0,sp_Pkt+dp_Port(a2) ;=> ReplyPort for packet moveq #ACTION_INHIBIT,d0 ;dospacket type/action (=INHIBIT) move.l d0,sp_Pkt+dp_Type(a2) ;========================= move.l d2,sp_Pkt+dp_Arg1(a2) ; dospacket Arg # ; 1 = disable drive task # ; 0 = enable drive task # ;========================= ;=========================================================================== ; Get MessagePort of process that controls the drive (trackdisk?) # ;=========================================================================== move.l a3,d1 ;DrivePort = DeviceProc(drivename) CALLDOS DeviceProc bne.s .cnt1 move.l #218,d2 bra.s .end .cnt1 ;=========================================================================== ; Now send the StandardPacket to the drive process # ;=========================================================================== move.l d0,a0 ;MessagePort of drive task move.l a2,a1 ;packet (message) CALLEXEC PutMsg ;=========================================================================== ; Check result & exit # ;=========================================================================== moveq #0,d2 ;error code ;WAIT UNTIL WE GET A MESSAGE BACK move.l d4,a0 ;our task's reply port CALL WaitPort cmp.l d0,a2 ;is it the right reply message? beq.s .cnt2 moveq #100,d2 ;dos failure/wrong reply message .cnt2 ;REMOVE PACKET FROM LIST move.l a2,a1 ;remove packet from list CALLEXEC Remove tst.l sp_Pkt+dp_Res1(a2) ;check result bne.s .end moveq #126,d0 .end ;EXIT WITH ERROR IN D0 move.l a2,a1 ;free memory for StandardPacket moveq #sp_SIZEOF,d0 CALLEXEC FreeMem move.l d2,d0 rts ;=========================================================================== _DOSBase dc.l 0 rawwindow dc.l 0 buffer dc.l 0 _DOSName dc.b "dos.library",0 rawwindowname dc.b "RAW:120/78/400/100/GetDrive",0 drivename dc.b "DF0:",0 not_mounted dc.b 10," Drive not mounted!",10,10,0 doserror dc.b 10," DOS Error. Packet reply failure!",10,10,0 drive_in_use dc.b 10," Can't get drive (in use?)",10,10,0 drive_disabled dc.b 10," Drive DF0: disabled.",10,10,0 press_key dc.b " Press any key to return...",10,10