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*******************************************************************************************
* sample.library.asm -- Example run-time library source code
*
* Assemble and link, without startup code, to create Sample.library,
* a LIBS: drawer run-time shared library
*
* Linkage Info:
* FROM sample.library.o
* LIBRARY LIB:Amiga.lib
* TO sample.library
*******************************************************************************************
SECTION code
NOLIST
INCLUDE "exec/types.i"
INCLUDE "exec/initializers.i"
INCLUDE "exec/libraries.i"
INCLUDE "exec/lists.i"
INCLUDE "exec/alerts.i"
INCLUDE "exec/resident.i"
INCLUDE "libraries/dos.i"
INCLUDE "sampleinclude/asmsupp.i"
INCLUDE "sampleinclude/samplebase.i"
INCLUDE "sampleinclude/sample_rev.i"
LIST
XDEF InitTable ;------ These don't have to be external but it helps
XDEF Open ;------ some debuggers to have them globally visible
XDEF Close
XDEF Expunge
XDEF Null
XDEF LibName
XDEF Double
XDEF AddThese
XREF _AbsExecBase
XLIB OpenLibrary
XLIB CloseLibrary
XLIB Alert
XLIB FreeMem
XLIB Remove
; 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 library).
Start:
MOVEQ #-1,d0
rts
;------------------------------------------------------------------------------------------
; A romtag structure. Both "exec" and "ramlib" look for this structure to discover magic
; constants about you (such as where to start running you from...). The include file
; sample_rev.i (created by hand or preferable with the developer tool ``bumprev''
; resolves the VERSION, REVISION, and VSTRING.
;------------------------------------------------------------------------------------------
; Few people will need a priority and should leave it at zero. The RT_PRI field is used
; in configuring the ROMs. Use "mods" from wack to look at other romtags in the system.
MYPRI EQU 0
RomTag:
;STRUCTURE RT,0
DC.W RTC_MATCHWORD ; UWORD RT_MATCHWORD
DC.L RomTag ; APTR RT_MATCHTAG
DC.L EndCode ; APTR RT_ENDSKIP
DC.B RTF_AUTOINIT ; UBYTE RT_FLAGS
DC.B VERSION ; UBYTE RT_VERSION (defined in sample_rev.i)
DC.B NT_LIBRARY ; UBYTE RT_TYPE
DC.B MYPRI ; BYTE RT_PRI
DC.L LibName ; APTR RT_NAME
DC.L IDString ; APTR RT_IDSTRING
DC.L InitTable ; APTR RT_INIT table for InitResident()
; this is the name that the library will have
LibName: SAMPLENAME
; standard name/version/date ID string from bumprev-created sample_rev.i
IDString: VSTRING
dosName: DOSNAME
; 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.
InitTable:
DC.L SampleBase_SIZEOF ; size of library base data space
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
;------ my libraries definitions
dc.l Double
dc.l AddThese
;------ 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 routines are
; in the file "exec/initializers.i". 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.
; NOTE - LN_TYPE below is a correction - old example had LH_TYPE.
dataTable:
INITBYTE LN_TYPE,NT_LIBRARY
INITLONG LN_NAME,LibName
INITBYTE LIB_FLAGS,LIBF_SUMUSED!LIBF_CHANGED
INITWORD LIB_VERSION,VERSION
INITWORD LIB_REVISION,REVISION
INITLONG LIB_IDSTRING,IDString
DC.L 0
; This routine gets called after the library has been allocated. The library pointer is
; in D0. The segment list is in A0. If it returns non-zero then the library will be
; linked into the library list.
initRoutine:
;------ get the library pointer into a convenient A register
move.l a5,-(sp)
move.l d0,a5
;------ save a pointer to exec
move.l a6,sb_SysLib(a5)
;------ save a pointer to our loaded code
move.l a0,sb_SegList(a5)
;------ open the dos library
lea dosName(pc),a1
CLEAR d0
CALLSYS OpenLibrary
move.l d0,sb_DosLib(a5)
bne.s 1$
;------ can't open the dos! what gives
ALERT AG_OpenLib!AO_DOSLib
1$:
;------ now build the static data that we need
;
; put your initialization here...
;
move.l a5,d0
move.l (sp)+,a5
rts
;------------------------------------------------------------------------------------------
; here begins the system interface commands. When the user calls OpenLibrary/CloseLibrary/
; RemoveLibrary, this eventually gets translated into a call to the following routines
; (Open/Close/Expunge). Exec has already put our library pointer in A6 for us. Exec has
; turned off task switching while in these routines (via Forbid/Permit), so we should not
; take too long in them.
;------------------------------------------------------------------------------------------
; Open returns the library pointer in d0 if the open was successful. If the open failed
; then null is returned. It might fail if we allocated memory on each open, or if only
; open application could have the library open at a time...
Open: ; ( libptr:a6, version:d0 )
;------ mark us as having another opener
addq.w #1,LIB_OPENCNT(a6)
;------ prevent delayed expunges
bclr #LIBB_DELEXP,sb_Flags(a6)
move.l a6,d0
rts
; There are two different things that might be returned from the Close routine. If the
; library is no longer open and there is a delayed expunge then Close should return the
; segment list (as given to Init). Otherwise close should return NULL.
Close: ; ( libptr:a6 )
;------ set the return value
CLEAR d0
;------ mark us as having one fewer openers
subq.w #1,LIB_OPENCNT(a6)
;------ see if there is anyone left with us open
bne.s 1$
;------ see if we have a delayed expunge pending
btst #LIBB_DELEXP,sb_Flags(a6)
beq.s 1$
;------ do the expunge
bsr Expunge
1$:
rts
; There are two different things that might be returned from the Expunge routine. If
; the library is no longer open then Expunge should return the segment list (as given
; to Init). Otherwise Expunge should set the delayed expunge flag and return NULL.
;
; One other important note: because Expunge is called from the memory allocator, it may
; NEVER Wait() or otherwise take long time to complete.
Expunge: ; ( libptr: a6 )
movem.l d2/a5/a6,-(sp)
move.l a6,a5
move.l sb_SysLib(a5),a6
;------ see if anyone has us open
tst.w LIB_OPENCNT(a5)
beq 1$
;------ it is still open. set the delayed expunge flag
bset #LIBB_DELEXP,sb_Flags(a5)
CLEAR d0
bra.s Expunge_End
1$:
;------ go ahead and get rid of us. Store our seglist in d2
move.l sb_SegList(a5),d2
;------ unlink from library list
move.l a5,a1
CALLSYS Remove
;
; device specific closings here...
;
;------ close the dos library
move.l sb_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
;------ set up our return value
move.l d2,d0
Expunge_End:
movem.l (sp)+,d2/a5/a6
rts
Null:
CLEAR d0
rts
;------------------------------------------------------------------------------------------
; Here begins the library specific functions. Both of these simple functions are entirely
; in assembler, but you can write your functions in C if you wish and interface to them
; here. If, for instance, the bulk of the AddThese function was written in C, you could
; interface to it as follows:
;
; - write a C function addTheseC(n1,n2) and compile it
; - XDEF _addThese C in this library code
; - change the AddThese function code below to:
; move.l d1,-(sp) ;push rightmost C arg first
; move.l d0,-(sp) ;push other C arg(s), right to left
; jsr _addTheseC ;call the C code
; addq #8,sp ;fix stack
; rts ;return with result in d0
;------------------------------------------------------------------------------------------
*----- Double(d0)
Double:
lsl #1,d0
rts
*----- AddThese(d0,d1)
AddThese:
add.l d1,d0
rts
; EndCode is a marker that show the end of your code. Make sure it does not span
; sections nor is before the rom tag in memory! 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.
EndCode:
END