mac-rom/Tidbits/ROvr.a
Elliot Nunn 4325cdcc78 Bring in CubeE sources
Resource forks are included only for .rsrc files. These are DeRezzed into their data fork. 'ckid' resources, from the Projector VCS, are not included.

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2017-12-26 09:52:23 +08:00

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