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sample.library.asm
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Assembly Source File
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1992-09-03
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11KB
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331 lines
*******************************************************************************************
* 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
*
*BLink from sample.library.o LIB LIB:amiga.lib TO sample.library
* Copyright (c) 1992 Commodore-Amiga, Inc.
*
* This example is provided in electronic form by Commodore-Amiga, Inc. for
* use with the "Amiga ROM Kernel Reference Manual: Libraries", 3rd Edition,
* published by Addison-Wesley (ISBN 0-201-56774-1).
*
* The "Amiga ROM Kernel Reference Manual: Libraries" contains additional
* information on the correct usage of the techniques and operating system
* functions presented in these examples. The source and executable code
* of these examples may only be distributed in free electronic form, via
* bulletin board or as part of a fully non-commercial and freely
* redistributable diskette. Both the source and executable code (including
* comments) must be included, without modification, in any copy. This
* example may not be published in printed form or distributed with any
* commercial product. However, the programming techniques and support
* routines set forth in these examples may be used in the development
* of original executable software products for Commodore Amiga computers.
*
* All other rights reserved.
*
* This example is provided "as-is" and is subject to change; no
* warranties are made. All use is at your own risk. No liability or
* responsibility is assumed.
*******************************************************************************************
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