217 lines
9.7 KiB
Plaintext
217 lines
9.7 KiB
Plaintext
;
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; File: ROvr.a
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;
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; Contains: ROM resource override code -- 'ROvr' (0)
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;
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; Written by: Brian B. McGhie and Darin Adler
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;
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; Copyright: © 1986-1992 by Apple Computer, Inc., all rights reserved.
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;
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; Change History (most recent first):
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;
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; <SM1> 4/23/92 CS Apply changes from reality:
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; <8> 3/16/92 DTY #1024511:
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; #1024511: Move ROZ cutback code back to ResourceMgrPatches.a
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; <7> 3/4/91 dba dty: get rid of SysVers conditionals
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; <6> 2/8/91 dba dty, #66370: reverting back to the old algorithm for finding
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; ROv# resources; why did I ever change it?
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; <5> 7/30/90 stb NEEDED FOR SIXPACK: replace ROZ cutback with another version
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; <4> 6/29/90 DDG NEEDED FOR SIXPACK: Now if hasSwitchLaunchPrevention is true,
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; the header is version seven and if it is false, the header is
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; version three (the old version number).
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; <3> 6/26/90 CCH NEEDED FOR SIXPACK: Added code to cutback size of ROM resource
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; map by about 5k on $67c ROM-based machines.
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; <2> 6/6/90 DTY Added a check to the ROM Override to determine if the system is
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; in the process of switch-launching from an older system to
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; System 7.0. If so, install a patch on _InitFonts to prevent this
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; switch launch from completing, and revert back to the previous
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; System file. Added additional check for value of SysVersion to
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; allow network booting to work.
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; <1.1> 8/30/89 dba changed to find ROv# resources by ID instead of by embedded
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; version number; rewrote to fix bug with resources not in ROM
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; (use one-deep calls)
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; <1.0> 11/16/88 CCH Added to EASE.
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;
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; 'ROvr' is the resource that the Resource Mgr looks for when loading in a new
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; System file. 'ROv#' is a resource type that contains which resources
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; in the ROM to override. The structure for 'ROv#' is as follows:
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;
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; 'ROv#':
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; version dc.w $0075 ; ROM version (ignored)
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; count dc.w $00XX ; # of resources in list minus one
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; type.0 dc.l 'WDEF' ; resource type to override
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; id.0 dc.w $0000 ; resource ID
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; type.1 dc.l 'PACK' ; resource type to override
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; id.1 dc.w $0004 ; resource ID
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; ...
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; type.XX dc.l 'CURS' ; resource type to override
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; id.XX dc.w $0002 ; resource ID
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;
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; NOTE: Previous versions of ROvr cycled through all of the 'ROv#' resources
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; and obeyed any which had the proper ROM version. This version looks only at
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; the 'ROv#' with the ROM version as its ID, and ignores the embedded version.
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;
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; The first instruction in 'ROvr' should be a bra.s past the version word
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; of 'ROvr'. This will enable install programs to determine if you have
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; the latest 'ROvr' resource, and replace it with a newer one.
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load 'StandardEqu.d'
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include 'ResourceMgrPriv.a'
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macro
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ResourceVersionHeader &type,&id,&version
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bra.s @skipHeader
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dc.l (&type)
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dc.w (&id)
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dc.w (&version)
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@skipHeader:
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endm
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kBranchSize equ 2 ; Size of short branch instruction in bytes
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kMinSystem equ $0700 ; Minimum System version to allow switch launching from
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kpatchType equ 'proc' ; _InitFonts patch is in a 'proc' resource
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kpatchID equ -16495 ; Resource ID of patch
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kInitFontsTrap equ $FE ; Trap word of _InitFonts
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ROvr main
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ResourceVersionHeader 'ROvr',0,8 ; The Big Bang ROvr (more patches for your bucks!)
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tst.w SysVersion ; At boot, SysVersion is not initialised, so we need a special
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beq.s DoOverrides ; case to allow normal ROM overriding at boot.
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cmpi.w #kMinSystem,SysVersion ; If SysVersion is System 7.0 or greater, allow switch launching.
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bge.s DoOverrides ; (Network booting)
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; If SysVersion was initialized, then we’re being called during a switch launch.
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; Since we don’t want to allow this switch launch to finish, we need to go back to the previously running
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; system. In the switch launch code for Finder 6.x, _InitResources is called, then _InitFonts, then the working
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; directory reference number of the new System Folder is saved in BootDrive.
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; Now that we’ve determined that we don’t want to switch launch, put a patch on _InitFonts which will close the
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; System 7 (or newer) System file, re-open the old one, and rebuild the System resource map. The patch also
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; bumps the return address past the instructions that stash the new WDRefNum in BootDrive, since up to this
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; point, BootDrive still contains the WDRefNum of the previous System Folder. This fact makes life incredibly
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; simple, and no hocus pocus has to be performed to figure out where the last System file was.
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; The patch is in 'proc' -16495.
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sub.w #4,sp
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move.l #kPatchType,-(sp)
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move.w #kPatchID,-(sp)
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_GetResource ; Get a handle to our patch
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tst.l (a1)
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bne.s PatchInitFonts ; If the handle we got back was good, install the patch
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moveq #dsBadPatch,d0 ; Generate a System Error if _GetResource returned nil
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_SysError
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PatchInitFonts
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move.l (sp),a1
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_DetachResource ; Detach it so it’ll stick around
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move.w #kInitFontsTrap,d0
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_GetTrapAddress ; Get the current _InitFonts routine
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move.l (a1),a1
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move.l a0,kBranchSize(a1) ; Save the address of _InitFonts
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move.l a1,a0
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move.w #kInitFontsTrap,d0
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_SetTrapAddress ; Patch it
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bra ExitROvr ; Get out of here. <3>
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;————————————————————————————————————————————————————————————————————————————————————————————————————
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;
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DoOverrides
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;
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; Version 3 ROvr code starts here
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;
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movem.l d2/a2-a3,-(sp) ; save working registers <5><3>
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move.l ROMMapHndl,a2 ; need to save ROM map attributes
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move.l (a2),a0 ; dereference map handle
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move.w MAttr(a0),-(sp) ; save off current ROM map attributes
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clr.w MAttr(a0) ; clear all ROM map attributes for this routine
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;————————————————————————————————————————————————————————————————————————————————————————————————————
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; load override resources
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moveq #1,d2 ; start with ROv# index of 1 <6>
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ForEachOverrideList
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subq #4,sp ; make space for handle
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move.l #'ROv#',-(sp) ; push 'ROv#' for _Get1IxResource
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move.w d2,-(sp) ; push resource index <6>
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move.w #mapTrue,ROMMapInsert ; link in ROM map w/ResLoad true
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_GetIndResource ; get ROv# resource (must be locked) <6>
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move.l (sp)+,d0 ; save handle to the list
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bz.s ROvrNOut ; no ROv#, so get out of here
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move.l d0,-(sp) ; save handle for ReleaseResource later
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move.l d0,a1 ; get ROv# resource handle
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move.l (a1),a1 ; get ROv# resource pointer
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move.l ROMBase,a0 ; get a pointer to the ROM <6>
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move.w 8(a0),d0 ; get the ROM version number <6>
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cmp.w (a1)+,d0 ; check if the ROv# is for this ROM <6>
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bne.s NextOverrideList ; if wrong version, go on to the next ROv# resource <6>
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move.w (a1)+,d1 ; count-1 of items in list
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ForEachResourceInList
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subq #4,sp ; make space for handle
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move.l (a1)+,-(sp) ; push type onto stack
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move.w (a1)+,-(sp) ; push id onto stack
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move.w #mapFalse,ROMMapInsert ; link in ROM map w/ResLoad false
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_Get1Resource
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move.l (sp)+,d0 ; get that resource
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bz.s NextResourceInList ; if no resource, advance to the next one
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move.l d0,-(sp) ; push handle for RmveResource later
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subq #4,sp ; make space for map entry offset
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move.l d0,-(sp) ; push resource handle onto stack
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move.w #mapFalse,ROMMapInsert ; link in ROM map w/ResLoad false
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st ResOneDeep ; since there is no one-deep version of RsrcMapEntry
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_RsrcMapEntry ; ignore errors from RsrcMapEntry
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move.l (sp)+,a0 ; get map entry offset
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add.l (a2),a0 ; make the map offset into a pointer
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clr.b RAttr(a0) ; clear the attributes for the resource (protected, etc.)
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; handle to remove is already on stack
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move.w #mapFalse,ROMMapInsert ; link in ROM map w/ResLoad false
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_RmveResource ; ignore errors from RmveResource
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; normally, we would do a DisposHandle here, but the ROM resources are
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; in their own special heap, and no-one cares about the wasted master pointer
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NextResourceInList
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dbra d1,ForEachResourceInList ; loop through the resources
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NextOverrideList
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_ReleaseResource ; handle to release is already on stack
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addq.w #1,d2 ; advance to next resource index <6>
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bra.s ForEachOverrideList ; go loop for the next resource <6>
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;————————————————————————————————————————————————————————————————————————————————————————————————————
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ROvrNOut
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move.l (a2),a0 ; dereference ROM map handle
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move.w (sp)+,MAttr(a0) ; restore ROM map attributes
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movem.l (sp)+,d2/a2-a3 ; restore working registers <6><5><3>
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ExitROvr ; Exit point after _InitFonts is patched
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lea ROvr,a0 ; get pointer to this resource
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_RecoverHandle ; get handle to this resource
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move.l (sp),-(sp) ; put the handle below a copy of the return address
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move.l a0,4(sp) ; put the handle on the stack for ReleaseResource
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_ReleaseResource autoPop ; release this resource and return
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endproc
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;————————————————————————————————————————————————————————————————————————————————————————————————————
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end
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