******************************************************************** * * Bovs.asm * Bryan's Overlay Supervisor * Copyright (C) 1991 Bryan Ford * ******************************************************************** * $Id$ * Assemble with A68k version >2.71 * If OVERLAY is 0, the overlay system is disabled. (This is how Bst.o is assembled.) OVERLAY set 1 include "exec/types.i" include "exec/tasks.i" include "exec/libraries.i" include "exec/alerts.i" include "exec/memory.i" include "exec/funcdef.i" include "exec/exec_lib.i" include "dos/dos.i" include "dos/dosextens.i" include "dos/rdargs.i" include "dos/dos_lib.i" include "workbench/startup.i" include "bry/macros.i" include "bry/memman.i" * Main program must define these: xref _stack ; Stack size for subprocess when run from CLI xref _procname ; Pointer to process name string xref _priority ; Priority for process detached from CLI xref _argtemplate ; ReadArgs template for 2.0 startup xref _argarray ; ReadArgs array of longwords to fill IFNE OVERLAY xdef _ovlyMgr ENDC xdef LockOverlay,UnlockOverlay,ResCall xdef @LockOverlay,@UnlockOverlay,_ResCall xdef BExit,_BExit,@BExit * Structure used to keep track of loaded overlays IFNE OVERLAY STRUCTURE OvNode,mmn_SIZEOF ; First a MemMan node BPTR on_SegList ; SegList for node if currently loaded UWORD on_LockCount ; Number of times this node is locked LABEL on_SIZEOF * Offsets within the overlay table. STRUCTURE OvTabEntry,0 ULONG ot_SeekOfs ; Load file position APTR ot_OvNode ; Pointer to OvNode structure LONG ot_dummy2 ULONG ot_Level ; Overlay level - always 1 ULONG ot_Ordinate ; Ordiinate number of node ULONG ot_FirstHunk ; Position to load into in hunk table ULONG ot_SymbolHunk ; Where symbol is found ULONG ot_SymbolOfs ; Where in that hunk LABEL ot_SIZEOF ENDC code NTRYHUNK xref _LinkerDB,__BSSBAS,__BSSLEN xref MMInit xref @Main first: IFNE OVERLAY bra startup cnop 0,4 * This next word serves to identify the overlay * supervisor to 'unloader'. dc.l $ABCD ; Magic unloader cookie loaddat: loadstream ds.l 1 ; Overlay input stream loadovtab ds.l 1 ; Overlay table (Machine address) loadhtab ds.l 1 ; Hunk table (BCPL address) loadglobvec ds.l 1 ; Global vector (Machine address) ENDC *** Startup code to initialize the overlay system and detach CLI processes startup: lea _LinkerDB,a4 ; Find data segment move.l 4,a6 ; Find exec.library lea __BSSBAS,a2 ; Clear undefined data moveq #0,d1 move.l #__BSSLEN,d2 bra.s 12$ 11$ move.l d1,(a2)+ 12$ dbf d2,11$ move.l a6,_SysBase(a4) ; Store SysBase for everyone else movem.l d0/a0,cliargs(a4) ; Store CLI argument line lea dosname(pc),a1 ; Open dos.library moveq #34,d0 ; Requires at least Kickstart 1.2 jsr _LVOOpenLibrary(a6) move.l d0,_DOSBase(a4) bz \fatalerr IFNE OVERLAY lea loadstream(pc),a2 ; Steal the file handle move.l (a2),stream(a4) clr.l (a2)+ move.l (a2)+,a5 ; Overlay data table (a5) move.l (a2),a3 ; Hunk table (a3) add.l a3,a3 add.l a3,a3 move.l -(a3),d0 ; Allocate room for a copy of both tables add.l -(a5),d0 subq.l #4,d0 move.l d0,d2 moveq #0,d1 jsr _LVOAllocMem(a6) tst.l d0 bz \fatalerr move.l d0,a0 ; Copy hunk table move.l d2,(a0)+ move.l a0,htab(a4) move.l (a3)+,d0 lsr.l #2,d0 subq.l #1+1,d0 21$ move.l (a3)+,(a0)+ dbra d0,21$ move.l (a5)+,d0 move.l (a5),d1 ; Find first overlay data table node lsl.l #2,d1 add.l a0,d1 move.l d1,ovdtab(a4) lsr.l #2,d0 ; Copy overlay table subq.l #1+1,d0 22$ move.l (a5)+,(a0)+ dbra d0,22$ move.l a0,ovdtabend(a4) ENDC jsr MMInit ; Initialize the memory manager tst.l d0 bz \fatalerr sub.l a1,a1 ; Which way did we come? jsr _LVOFindTask(a6) move.l d0,a2 tst.l pr_CLI(a2) bnz.s \fromcli \fromwb: lea pr_MsgPort(a2),a0 ; Get the startup message move.l a0,d2 jsr _LVOWaitPort(a6) move.l d2,a0 jsr _LVOGetMsg(a6) move.l d0,a3 move.l a3,_WBenchMsg(a4) move.l sm_ArgList(a3),a1 ; Use program's directory move.l wa_Lock(a1),d1 move.l _DOSBase(a4),a6 jsr _LVOCurrentDir(a6) move.l sp,origsp(a4) ; Set things up for exit pea _BExit moveq #0,d0 ; Call the main program move.l a3,a0 jmp @Main \fromcli: move.l a2,parenttask(a4) ; Make sure child knows where to find us move.l #SIGBREAKF_CTRL_F,d7 ; Make sure CTRL-F flag is cleared move.l d7,d1 moveq #0,d0 jsr _LVOSetSignal(a6) move.l _DOSBase(a4),a6 cmp.w #36,LIB_VERSION(a6) ; Use 2.0's ReadArgs if possible blo.s 79$ move.l #_argtemplate,d1 move.l #_argarray,d2 moveq #0,d3 jsr _LVOReadArgs(a6) move.l d0,rdargs(a4) bz \doserr 79$ move.l pr_CurrentDir(a2),d1 ; Get an initial directory for the subprocess jsr _LVODupLock(a6) move.l d0,dupdir(a4) move.l _procname,d1 ; Start the child process move.l _priority,d2 move.l #cliseg,d3 lsr.l #2,d3 move.l _stack,d4 jsr _LVOCreateProc(a6) tst.l d0 bz \doserr move.l d0,a2 lea -pr_MsgPort(a2),a2 move.l d7,d0 ; Wait for the go-ahead from the child move.l _SysBase(a4),a6 jsr _LVOWait(a6) lea first-4(pc),a0 ; Detach the segment list move.l (a0),splitseg(a4) clr.l (a0) moveq #0,d0 ; Return success code immediately rts \doserr: cmp.w #36,LIB_VERSION(a6) ; Display an appropriate error message blo.b \fatalerr jsr _LVOIoErr(a6) move.l d0,d1 move.l _procname,d2 jsr _LVOPrintFault(a6) \fatalerr: jmp errexit dosname dc.b "dos.library",0 code text xref MMFinish,MMAddNode,MMRemNode IFNE OVERLAY *** Entrypoint called by the linker when overlaid functions are called * d0 = Entrypoint number * a0/a1 = Parameters from caller _ovlyMgr: movem.l d2-d3/a0-a3/a5-a6,-(sp) ; 8 longwords move.l ovdtab,a3 ; Find overlay data table node (a3) move.l a3,a2 lsl.w #2,d0 adda.w d0,a3 move.l ot_OvNode(a3),d0 ; See if we already know its OvNode bnz.s \alreadyfound move.l ot_SeekOfs(a3),d0 ; Find the first entry in this node (a2) moveq #ot_SIZEOF,d1 bra.s \findfirst_a \findfirst: add.l d1,a2 \findfirst_a: cmp.l ot_SeekOfs(a2),d0 bne.s \findfirst move.l ot_OvNode(a2),d0 ; See if the OvNode is already allocated bnz.s \alreadyallocated \retryalloc: moveq #on_SIZEOF,d0 ; Allocate the OvNode move.l #MEMF_PUBLIC!MEMF_CLEAR,d1 move.l 4,a6 jsr _LVOAllocMem(a6) move.l d0,ot_OvNode(a2) ; Store the OvNode in the first OvTabEntry bz.s \retryalloc ; FIXME: Shouldn't there be a better way? move.l d0,a0 ; Initialize the node lea getridfunc(pc),a1 move.l a1,mmn_GetRidFunc(a0) move.l a0,mmn_GetRidData(a0) \alreadyallocated: move.l d0,ot_OvNode(a3) ; Store OvNode into current OvTabEntry \alreadyfound: move.l d0,a5 ; OvNode into (a5) move.l a5,a1 ; Lock this node in memory during the call bsr lockoverlay move.l on_SegList(a5),d0 ; See if the code is loaded bnz \alreadyloaded lea rescallret(pc),a0 ; Don't load if the call is coming through ResCall cmp.l 8*4(sp),a0 beq \rescallquit ; Note: D0 = 0 from above test * Now seek to the segment and load it. If we fail (probably because * the user removed the disk), then retry until successful. This has * the effect of continually reprompting the user to insert the disk * until he/she obeys. move.l _DOSBase,a6 \retryload: move.l stream,d1 ; Find hunk position in load file move.l ot_SeekOfs(a3),d2 moveq #OFFSET_BEGINNING,d3 jsr _LVOSeek(a6) tst.l d0 bmi.s \retryload moveq #0,d1 ; Special calling format - NULL for name move.l htab,d2 ; Hunk table lsr.l #2,d2 move.l stream,d3 ; File handle jsr _LVOLoadSeg(a6) move.l d0,on_SegList(a5) ble.s \retryload \alreadyloaded: move.w ot_SymbolHunk+2(a3),d1 ; Find hunk function is in sub.w ot_FirstHunk+2(a3),d1 bra.b \hunkhuntin \hunkhunt move.l (a2),d0 \hunkhuntin lsl.l #2,d0 move.l d0,a2 dbra d1,\hunkhunt add.l ot_SymbolOfs(a3),a2 ; Call function (d0=OvNode, a0-a1=Passed) move.l a5,d0 movem.l 8(sp),a0-a1 jsr (a2) \rescallquit move.l d0,d2 ; Unlock the node move.l a5,a1 bsr unlockoverlay move.l d2,d0 movem.l (sp)+,d2-d3/a0-a3/a5-a6 rts *** Lock an OvNode LockOverlay: @LockOverlay: move.l d0,a1 lockoverlay: addq.w #1,on_LockCount(a1) ; Increment nesting counter bra MMRemNode ; Take the node off the dead-list *** Unlock an OvNode UnlockOverlay: @UnlockOverlay: move.l d0,a1 unlockoverlay: subq.w #1,on_LockCount(a1) ; Decrement nesting counter bz MMAddNode ; If zero, add to the dead-list rts *** Special call routine - calls a function ONLY if it's already resident *** (if it's not resident, it returns immediately without loading the function.) * a2 = Pointer to routine to call * a0-a1 = Parameters to routine * d0 = Return value from routine if resident, zero if the routine wasn't resident. ResCall: _ResCall: jsr (a2) rescallret ; ovlyMgr watches for this return address... rts ENDC *** Fake the LockOverlay and UnlockOverlay functions for the non-overlaid versions IFEQ OVERLAY LockOverlay: @LockOverlay: UnlockOverlay: @UnlockOverlay: rts ResCall: _ResCall: jmp (a2) ENDC *** Fake SegList for the CLI subprocess to start at cnop 0,4 dc.l 0 ; Segment size cliseg: dc.l 0 ; Link to next segment lea _LinkerDB,a4 ; Find the data segment move.l sp,origsp(a4) ; Save the stack pointer movem.l cliargs(a4),d2/a0 ; Copy the arguments move.l d2,d0 addq.l #4-1,d0 andi.b #$fc,d0 sub.l d0,sp move.l sp,a1 move.l d2,d0 bra.s 12$ 11$ move.b (a0)+,(a1)+ 12$ dbra d0,11$ move.l _SysBase(a4),a6 ; Signal parent task to get lost move.l parenttask(a4),a1 move.l #SIGBREAKF_CTRL_F,d0 jsr _LVOSignal(a6) move.l _DOSBase(a4),a6 ; Set the initial directory move.l dupdir(a4),d1 jsr _LVOCurrentDir(a6) move.l d2,d0 ; Call the main program move.l sp,a0 jsr @Main ; fall through... *** Exit code for the sub-process BExit: _BExit: @BExit: lea _LinkerDB,a4 ; Restore data segment move.l origsp(a4),sp ; Restore SP errexit: move.l _DOSBase(a4),a6 move.l rdargs(a4),d1 ; Free all command-line arguments bz.s 79$ jsr _LVOFreeArgs(a6) 79$ IFNE OVERLAY move.l stream(a4),d1 ; Close load file bz.s 49$ jsr _LVOClose(a6) ENDC 49$ move.l dupdir(a4),d1 ; Free the initial directory bz.s 59$ jsr _LVOUnLock(a6) 59$ move.l _SysBase(a4),a6 IFNE OVERLAY move.l ovdtab(a4),d0 ; Free all overlays bz.s 19$ move.l d0,a2 move.l ovdtabend(a4),a3 moveq #0,d2 1$ move.l ot_OvNode(a2),d0 bz.s 18$ move.l d0,a5 move.l ot_SeekOfs(a2),d0 ; Only one OvNode per SeekOfs cmp.l d0,d2 beq.s 18$ move.l d0,d2 move.l a5,a0 ; Unload the SegList bsr getridfunc move.l a5,a1 moveq #on_SIZEOF,d0 jsr _LVOFreeMem(a6) 18$ lea ot_SIZEOF(a2),a2 cmp.l a2,a3 bne.s 1$ 19$ move.l htab(a4),d0 ; Free the hunk and overlay tables bz.s 29$ move.l d0,a1 move.l -(a1),d0 jsr _LVOFreeMem(a6) ENDC 29$ move.l _WBenchMsg(a4),d2 ; Return the Workbench message bz.s 39$ jsr _LVOForbid(a6) ; Don't let Workbench unload us yet! move.l d2,a1 jsr _LVOReplyMsg(a6) 39$ move.l _DOSBase(a4),d2 ; Close dos.library bz.s 69$ move.l d2,a1 jsr _LVOCloseLibrary(a6) 69$ bsr MMFinish ; Close down the memory manager move.l splitseg(a4),d1 ; Unload the program code bz.s 99$ move.l d2,a6 jmp _LVOUnLoadSeg(a6) 99$ moveq #10,d0 ; Always return an error code rts ; (If anybody sees it, something went wrong.) *** Get rid of an OvNode's SegList * a0 = OvNode * Returns: * d0 = Nonzero if we freed anything IFNE OVERLAY getridfunc: movem.l a2/a6,-(sp) move.l a0,a2 move.l a0,a1 ; No need to keep it on the dead-list bsr MMRemNode move.l on_SegList(a2),d0 ; Un-load the SegList bz.b \out move.l d0,d1 move.l _DOSBase,a6 jsr _LVOUnLoadSeg(a6) clr.l on_SegList(a2) moveq #1,d0 \out movem.l (sp)+,a2/a6 rts ENDC bss __MERGED xdef _SysBase,_DOSBase,_WBenchMsg _SysBase ds.l 1 ; System libraries _DOSBase ds.l 1 _WBenchMsg ds.l 1 ; If we came from Workbench IFNE OVERLAY stream ds.l 1 ; Load file handle htab ds.l 1 ; Fake hunk table ovdtab ds.l 1 ; Overlay data table ovdtabend ds.l 1 ; End of overlay data table ENDC splitseg ds.l 1 ; First segment after NTRYHUNK origsp ds.l 1 ; Original sub-process SP cliargs: ; Command-line arguments cliarglen ds.l 1 cliargstr ds.l 1 dupdir ds.l 1 ; DupLock'd directory we need to free parenttask ds.l 1 ; Original CLI process rdargs ds.l 1 ; RDArgs structure returned by ReadArgs end