;----------------------------------------------------------------- ; ; mylib.asm -- example library code ; ; Example of how a user system library is constructed. ; ; © Copyright 1988 Steve Simpson ; ; History: ; 90-05-06 created ; ; assemble: as mylib.asm ; link: ln -o mylib.library mylib.o _myfunc2.o c.lib ; ;----------------------------------------------------------------- SECTION section NOLIST INCLUDE "exec/types.i" INCLUDE "exec/nodes.i" INCLUDE "exec/lists.i" INCLUDE "exec/libraries.i" INCLUDE "exec/alerts.i" INCLUDE "exec/resident.i" INCLUDE "exec/initializers.i" INCLUDE "libraries/dos.i" INCLUDE "libsupp.i" INCLUDE "mylib_def.i" LIST ;------------------------------------------------------------------- ; external definitions and references ;------------------------------------------------------------------- XDEF Init XDEF Open XDEF Close XDEF Expunge XDEF Null XDEF myName XDEF MyFunc0 XDEF MyFunc1 XDEF __MyFunc2 XREF _AbsExecBase XLIB OpenLibrary XLIB CloseLibrary XLIB Alert XLIB FreeMem XLIB Remove ;----------------------------------------------------------------------- ;The first executable location. This returns an error in case someone ;tried to run the library as a program. ;----------------------------------------------------------------------- LibStart: CLEAR d0 rts ;----------------------------------------------------------------------- ; various definitions and equates ;----------------------------------------------------------------------- ;library priority MYPRI EQU 0 ;a major version number VERSION EQU 1 ;a particular revision. This should uniqley identify the library REVISION EQU 1 ;---------------------------------------------------------------------- ;A romtag structure. ;´exec´ and ´ramlib´ look for this structure during the loading operation ;to discover such as where to start running it, for example. ;In C this would be equivalent to the Resident structure ;--------------------------------------------------------------------- initLibDescrip: ;structure RT,0 dc.w RTC_MATCHWORD ;UWORD RT_MATCHWORD dc.l initLibDescrip ;APTR RT_MATCHTAG dc.l EndLibCode ;APTR RT_ENDSKIP dc.b RTF_AUTOINIT ;UBYTE RT_FLAGS dc.b VERSION ;UBYTE RT_VERSION dc.b NT_LIBRARY ;UBYTE RT_TYPE dc.b MYPRI ;UBYTE RT_PRI dc.l myName ;APTR RT_NAME dc.l libIdString ;APTR RT_IDSTRING dc.l libInit ;APRT RT_INIT ;LABEL RT_SIZE ;my library name myName MYLIBNAME ;--------------------------------------------------------------------- ;library identifier tag used in supporting the library ;format is 'name version.revision (dd mon yyyy)',,, ;--------------------------------------------------------------------- libIdString dc.b 'mylib 1.0 (06 May 1988)',13,10,0 ;name of dos library to open dosName DOSNAME ;we need word alignmemt ds.w 0 ;--------------------------------------------------------------------- ;the romtag specifies "RTF_AUTOINIT". The RT_INIT structure field ;points to the following table. If RTF_AUTOINIT was not set, then ;RT_INIT would point to a initialisation routine to run. ;These data are used by the loading program as parameters to ;AddLibrary() library initialisation. ;--------------------------------------------------------------------- libInit: dc.l MyLib_Sizeof ;data space size dc.l funcTable ;pointer to function initialisers dc.l dataTable ;pointer to data initialisers dc.l initRoutine ;routine to run ;--------------------------------------------------------------------- ;table of addresses of mylib functions ;--------------------------------------------------------------------- funcTable: ;standard system routines - these MUST always be included dc.l Open dc.l Close dc.l Expunge dc.l ExtFunc ;my library´s definitions dc.l MyFunc0 dc.l MyFunc1 dc.l __MyFunc2 ;function table end marker dc.l -1 ;--------------------------------------------------------------------- ;this data table initialises static data structures. The format is ;specified in exec/InitStruct routine´s manual pages. ;The first argument is the offset from the library base for this ;byte/word/long. The second argument is the value to put in that cell. ;The table is null terminated. ;--------------------------------------------------------------------- dataTable: INITBYTE LH_TYPE,NT_LIBRARY INITLONG LN_NAME,myName INITBYTE LIB_FLAGS,LIBF_SUMUSED!LIBF_CHANGED INITWORD LIB_VERSION,VERSION INITWORD LIB_REVISION,REVISION INITLONG LIB_IDSTRING,idString dc.l 0 ;--------------------------------------------------------------------- ;This is the initialisation routine ans is called after the library ;has been allocated. ;If it returns non-zero then the library will be linked into the ;library list. ;--------------------------------------------------------------------- initRoutine: ;( D0: lib. ptr., A0:segment list) ;get the library pointer into a A5 move.l a5,-(sp) move.l d0,a5 ;save pointer to exec move.l a6,ml_SysLib(a5) ;save a pointer to loaded code segment list move.l a0,ml_SegList(a5) ;open the dos.library lea dosName(pc),a1 CLEAR d0 CALLSYS OpenLibrary move.l d0,ml_DosLib(a5) bne.s 1$ ;can´t open dos ALERT AG_OpenLib!AO_DOSLib 1$: ;build the static data that we need ; ;library specific initialisations go here ; move.l a5,d0 move.l (sp)+,a5 rts ;---------------------------------------------------------------------- ;System interface commands begin here. Calling OpenLibrary/CloseLibrary/ ;RemoveLibrary, translates into a call to the routines Open/Close/Expunge. ;The library base pointer is in A6. Task switching has been turned off ;while in these routines (via Forbid/Permit), so don't hang about! ;--------------------------------------------------------------------- ;--------------------------------------------------------------------- ;Open returns the library pointer in D0 if the open was successful. ;If the open failed then null is returned. ;--------------------------------------------------------------------- Open: ;(libptr: A6, version: D0 ;increment library open counter addq.w #1,LIB_OPENCNT(a6) ;prevent delayed expunges bclr #LIBB_DELEXP,ml_Flags(a6) move.l a6,d0 rts ;--------------------------------------------------------------------- ;If the library is no longer open, Close returns the segment list if ;the delayed expunge flag is set. Otherwise Close return NULL. ;--------------------------------------------------------------------- Close: ;(libptr: a6) ;set the return value CLEAR d0 ;decrement library open counter subq.w #1,LIB_OPENCNT(a6) ;anyone got us open? bne.s 1$ ;any delayed expunge pending? btst #LIBB_DELEXP,ml_Flags(a6) beq.s 1$ ;do the expunge bsr Expunge 1$: rts ;--------------------------------------------------------------------- ;If the library is no longer open, then Expunge returns the segment ;list for the library code. Otherwise the delayed expunge flag is ;set and NULL is returned in D0. ;Expunge should never Wait, or take a long time to complete. ;--------------------------------------------------------------------- Expunge: ;(libptr: A6) movem.l d2/a5/a6,-(sp) move.l a6,a5 move.l ml_SysLib(a5),a6 ;anyone got us open? tst.w LIB_OPENCNT(a5) beq 1$ ;if still open - set delayed expunge flag bset #LIBB_DELEXP,ml_Flags(a5) CLEAR d0 bra.s Expunge_End 1$: ;we can remove ourselves here move.l ml_SegList(a5),d2 ;unlink from library list move.l a5,a1 CALLSYS Remove ; ;library specific closings here ; ;close the dos library move.l ml_DosLib(a5),a1 CALLSYS CloseLibrary ;free our memory CLEAR d0 move.l a5,a1 move.w LIB_NEGSIZE(a5),d0 sub.l d0,a1 add.w LIB_POSSIZE(a5),d0 CALLSYS FreeMem ;setup our return value - the seglist move.l d2,d0 Expunge_End: movem.l (sp)+,d2/a5/a6 rts ;--------------------------------------------------------------------- ;ExtFunc just returns 0 in D0 register. ;--------------------------------------------------------------------- ExtFunc: CLEAR d0 rts ;---------------------------------------------------------------------- ;The library specific commands begin here ;In this example library there are 3 library specific routines - ;the third __MyFunc2 is written in C, and is included in the link ;list for the library. ;---------------------------------------------------------------------- ;---------------------------------------------------------------------- ; MyFunc0 - just returns value 0 in the D0 register ;---------------------------------------------------------------------- MyFunc0: CLEAR d0 rts ;---------------------------------------------------------------------- ; MyFunc1 - returns contents of register A6 in the D0 register ;---------------------------------------------------------------------- MyFunc1: move.l a6,d0 rts ;---------------------------------------------------------------------- ;This is the end of our library code ;---------------------------------------------------------------------- EndLibCode: END