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7a948b68fa
NetBoot/ChainLoader.a
Elliot Nunn c7e7cb987b Fix multi-block write bug
2021-02-18 08:44:11 +08:00

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myUnitNum equ 52
myDRefNum equ ~myUnitNum
serverBufSize equ 32
Code
cmp.l #1,4(SP)
beq getBootBlocks
cmp.l #2,4(SP)
beq getSysVol
cmp.l #3,4(SP)
beq mountSysVol
move.l #-1,d0
rts
getBootBlocks
; Now is the time to install our DRVR because we are guaranteed an opportunity to boot if we don't fuck up.
link A6,#-$32
movem.l A2-A4/D3-D7,-(SP)
; Copy the DRVR -> A2
move.l #DrvrEnd-DrvrBase,D0
lea DrvrBase,A0
bsr InstallInSysHeap
move.l A0,A2
; Patch the server address into the DRVR code
move.l 12(A6),A0 ; global pointer
move.l 24(A0),D0 ; AddrBlock
lea gSaveAddr-DrvrBase(A2),A0
move.b #10,15(A0) ; hardcode DDP protocol ID
move.b D0,13(A0) ; socket
lsr.w #4,D0
lsr.w #4,D0
move.b D0,11(A0) ; node
swap D0
move.w D0,7(A0) ; network
; Patch the disk image name and size into the DRVR code
; bsr BootPicker ; A0 = pstring ptr
; lea gNumBlks-DrvrBase(A2),A1
; move.l -4(A0),(A1) ; the size is underneath the pstring ptr
; move.l -4(A0),D6 ; D6 = block count, needed for DQE
; lea gQFilename-DrvrBase(A2),A1 ; A1 = dest
; moveq.l #1,D0
; add.b (A0),D0
; dc.w $A22E ; _BlockMoveData
; Install the driver in the unit table
move.l #myDRefNum,D0
dc.w $A43D ; _DrvrInstall ReserveMem
; That call created a DCE. Find and lock.
move.l $11C,A0 ; UTableBase
move.l myUnitNum*4(A0),A0
dc.w $A029 ; _HLock
move.l (A0),A0
; Populate the empty DCE that DrvrInstall left us
move.l A2,0(A0) ; dCtlDriver is pointer (not hdl)
move.w 0(A2),D0 ; get DRVR.drvrFlags
bclr #6,D0 ; Clear dRAMBased bit (to treat dCtlDriver as a pointer)
move.w D0,4(A0) ; set DCE.dCtlFlags
move.w 2(A2),$22(A0) ; drvrDelay to dCtlDelay
move.w 4(A2),$24(A0) ; drvrEMask to dCtlEMask
move.w 6(A2),$26(A0) ; drvrMenu to dCtlMenu
; Open the driver
lea -$32(SP),SP
move.l SP,A0
bsr clearblock
lea DrvrNameString,A1
move.l A1,$12(A0) ; IOFileName
dc.w $A000 ; _Open
lea $32(SP),SP
; Create a DQE
move.l #$16,D0
dc.w $A71E ; _NewPtr ,Sys,Clear
add.l #4,A0 ; has some cheeky flags at negative offset
move.l A0,A3
lea gDQEAddr,A0
move.l A3,(A0)
; Populate the DQE
move.l D6,D0 ; needs fixing for Ruby Slipper
lsl.l #5,D0 ; convert to bytes
lsl.l #4,D0
swap D0
move.l D0,$C(A3) ; dQDrvSz/dQDrvSz2
move.l #$00080000,-4(A3) ; secret flags, see http://mirror.informatimago.com/next/developer.apple.com/documentation/mac/Files/Files-112.html
move.w #1,4(A3) ; qType
move.w #0,$A(A3) ; dQFSID should be for a native fs
; Into the drive queue (which will further populate the DQE)
bsr findFreeDriveNum ; get drvnum in D0
lea gDriveNum,A0
move.w D0,(A0)
swap D0
move.w #myDRefNum,D0 ; D0.H = drvnum, D0.L = drefnum
move.l D0,D3 ; we need this in a sec
move.l A3,A0
dc.w $A04E ; _AddDrive
; Open our socket
lea -$32(SP),SP
move.l SP,A0
bsr clearblock
move.w #-10,$18(A0) ; ioRefNum = .MPP
move.w #248,$1A(A0) ; csCode = openSkt
move.b #10,$1C(A0) ; socket = 10, same as ATBOOT uses
lea DrvrSockListener-DrvrBase(A2),A2
move.l A2,$1E(A0) ; listener
dc.w $A004 ; _Control
lea $32(SP),SP
; Get the real 1024k of boot blocks to a temp location
; (it will eventually get trashed, but we have time)
lea 4096(A5),A4 ; above BootGlobals
lea -$32(SP),SP
move.l SP,A0
bsr clearblock
move.l D3,22(A0) ; IOVRefNum=drvnum, IORefNum=drefnum
move.l A4,32(A0) ; IOBuffer
move.l #1024,36(A0) ; IOReqCount = 2 blocks
move.l #0,46(A0) ; IOPosOffset = 0
move.w #1,44(A0) ; IOPosMode = from start
dc.w $A002 ; _Read
lea $32(SP),SP
; Put the boot blocks in netBOOT's global data structure as requested
move.l A4,A0
move.l 12(A6),A1
lea $BA(A1),A1
move.l #$138,D0
dc.w $A22E ; _BlockMoveData
move.l A1,A0 ; A0 = truncated BBs
move.l A4,A1 ; A1 = full-length BBs
bsr HealInjuredBootBlocks
; Clean up our stack frame
movem.l (SP)+,A2-A4/D3-D7
unlk A6
move.l #0,D0
rts
getSysVol ; pointless call :(
move.l #0,D0
rts
mountSysVol
link A6,#-$32
movem.l A2-A4/D3,-(SP)
lea gDriveNum,A0
move.w (A0),D3
; System 7 needs MountVol to return the right vRefNum
move.l $366,A0 ; Steal existing PB from FSQHead
; Set aside the FS queue to stop MountVol deadlocking
move.w $360,-(SP) ; FSBusy
move.l $362,-(SP) ; FSQHead
move.l $366,-(SP) ; FSQTail
clr.w $360
clr.l $362
clr.l $366
; MountVol
bsr clearblock
move.w D3,$16(A0) ; ioVRefNum = ioDrvNum = the drive number
dc.w $A00F ; _MountVol
bne error
; Restore the FS queue
move.l (SP)+,$366
move.l (SP)+,$362
move.w (SP)+,$360
; Tattle about the DQE and VCB
move.l 4+12(A6),A1
move.l $356+2,A0 ; VCBQHdr.QHead (maybe I should be clever-er)
move.l A0,(A1)
move.l 4+16(A6),A1
lea gDQEAddr,A0
move.l (A0),(A1)
movem.l (SP)+,A2-A4/D3
unlk A6
move.l #0,d0
rts
error
move.w #$7777,D0
dc.w $A9C9
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
clearblock
move.w #$32/2-1,D0
.loop clr.w (A0)+
dbra D0,.loop
lea -$32(A0),A0
rts
findFreeDriveNum ; and return it in D0. Free to trash the usual registers
; Find a free drive number (nicked this code from BootUtils.a:AddMyDrive)
LEA $308,A0 ; [DrvQHdr]
MOVEQ #4,D0 ; start with drive number 4
.CheckDrvNum
MOVE.L 2(A0),A1 ; [qHead] start with first drive
.CheckDrv
CMP.W 6(A1),D0 ; [dqDrive] does this drive already have our number?
BEQ.S .NextDrvNum ; yep, bump the number and try again.
CMP.L 6(A0),A1 ; [qTail] no, are we at the end of the queue?
BEQ.S .GotDrvNum ; if yes, our number's unique! Go use it.
MOVE.L 0(A1),A1 ; [qLink] point to next queue element
BRA.S .CheckDrv ; go check it.
.NextDrvNum
; this drive number is taken, pick another
ADDQ.W #1,D0 ; bump to next possible drive number
BRA.S .CheckDrvNum ; try the new number
.GotDrvNum
rts
DrvrNameString
dc.b 8, ".LANDisk", 0
gDriveNum dc.w 0
gDQEAddr dc.l 0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrBase
dc.w $4F00 ; dReadEnable dWritEnable dCtlEnable dStatEnable dNeedLock
dc.w 0 ; delay
dc.w 0 ; evt mask
dc.w 0 ; menu
dc.w DrvrOpen-DrvrBase
dc.w DrvrPrime-DrvrBase
dc.w DrvrControl-DrvrBase
dc.w DrvrStatus-DrvrBase
dc.w DrvrClose-DrvrBase
dc.b 8, ".LANDisk", 0
g
gNumBlks dc.l 0 ; the source of all truth
gMyDCE dc.l 0
gExpectHdr dc.l 0
gProgress dc.l 0
gQuery dcb.b 20 ; really need to consider the length of this!
gWDS dcb.b 2+4+2+4+2+4+2 ; room for an address and two data chunks
gMyPB dcb.b $32+2 ; allow us to clear it with move.l's
odd
gSaveAddr dcb.b 16
gAddr dcb.b 16
even
; a0=iopb, a1=dce on entry to all of these...
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrOpen
move.l A0,-(SP)
lea gMyDCE,A0 ; dodgy, need this for IODone
move.l A1,(A0)
move.l (SP)+,A0
move.w #0,$10(A0) ; ioResult
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrPrime
; Convert the ioPosOffset in the parameter block to a block offset (allows large vol support).
btst.b #0,$2C(A0) ; test ioPosMode & kUseWidePositioning
bne.s .wide
.notwide move.l $10(A1),D0
bra.s .gotD0
.wide move.l $2E(A0),D0 ; the block offset can only be up to 32 bits
or.l $32(A0),D0
.gotD0 ror.l #4,D0 ; now D0 = (LS 23 bits) followed by (MS 9 bits)
ror.l #5,D0
move.l D0,$2E(A0) ; ioPosOffset = D0 = byte_offset/512
; Return with a "pending" ioResult.
move.w #1,$10(A0) ; ioResult = pending. We will return without an answer.
; Wang the state machine!
cmp.b #2,7(A0) ; ioTrap == _Read?
bne DrvrSendWrite ; transition from "Idle" to "Await Comp Send Write Packet"
bra DrvrSendRead ; transition from "Idle" to "Await Comp Send Read Packet"
; Some wrappers for the routines below...
DrvrSendRead
; Called from Prime routine or socket listener: PB/DCE in A0/A1 must be preserved (but we only require A0)
lea gExpectHdr,A2
clr.w (A2)+
addq.w #1,(A2) ; packet filter sequence word
lea gProgress,A2
clr.l (A2)
lea gSaveAddr,A2
lea gAddr,A3
move.b (A2)+,(A3)+ ; copy the address struct, dang it!
move.l (A2)+,(A3)+
move.l (A2)+,(A3)+
move.l (A2)+,(A3)+
move.w (A2)+,(A3)+
move.b (A2)+,(A3)+
lea gQuery,A2
move.w #$8000,(A2)+ ; Means a polite request
move.w gExpectHdr+2,(A2)+
move.l $28(A0),D0 ; [ioActCount (in bytes)
lsr.l #4,D0
lsr.l #5,D0 ; / 512]
add.l $2E(A0),D0 ; + ioPosOffset (in blocks)
move.l D0,(A2)+ ; -> "offset" field of request
move.l $24(A0),D0 ; [ioReqCount (in bytes)
sub.l $28(A0),D0 ; - ioActCount (in bytes)]
lsr.l #4,D0
lsr.l #5,D0 ; / 512
move.l D0,(A2)+ ; -> "length" field of request
lea gWDS,A2
clr.w (A2)+ ; WDS+0: reserved field
pea gAddr
move.l (SP)+,(A2)+ ; WDS+2: pointer to address struct
move.w #12,(A2)+ ; WDS: push pointer/length
pea gQuery
move.l (SP)+,(A2)+
clr.w (A2)+ ; WDS: end with zero
move.l A0,-(SP)
lea gMyPB,A0
bsr DrvrClearBlock
pea DrvrDidSendRead
move.l (SP)+,$C(A0) ; ioCompletion
move.w #-10,$18(A0) ; ioRefNum = .MPP
move.w #246,$1A(A0) ; csCode = writeDDP
move.b #10,$1C(A0) ; socket = 10 (hardcoded)
move.b #1,$1D(A0) ; set checksumFlag
pea gWDS
move.l (SP)+,$1E(A0) ; wdsPointer to our WriteDataStructure
dc.w $A404 ; _Control ,async
move.l (SP)+,A0
rts
DrvrDidSendRead
; Called as completion routine: PB/result in A0/D0, must preserve all registers other than A0/A1/D0-D2
lea gExpectHdr,A2
move.w #$8100,(A2) ; Enable packet reception
rts ; TODO: set up a timeout/retry task
DrvrSendWrite
; Called from Prime routine or socket listener: PB/DCE in A0/A1 must be preserved (but we only require A0)
; D1 = block index within chunk
move.l $28(A0),D1
lsr.l #5,D1
lsr.l #4,D1
move.l D1,D0
and.l #32-1,D1
move.l $28(A0),D2
add.l #512,D2
cmp.l $24(A0),D2
bne.s .notLastBlock
bset #7,D1
.notLastBlock
; D0 = first block of chunk
and.l #-32,D0
add.l $2E(A0),D0
tst.l D1
bne.s .notFirstBlockOfChunk
lea gExpectHdr,A2
clr.w (A2)+
addq.w #1,(A2) ; packet filter sequence word
.notFirstBlockOfChunk
lea gSaveAddr,A2
lea gAddr,A3
move.b (A2)+,(A3)+ ; copy the address struct, dang it!
move.l (A2)+,(A3)+
move.l (A2)+,(A3)+
move.l (A2)+,(A3)+
move.w (A2)+,(A3)+
move.b (A2)+,(A3)+
lea gQuery,A2
move.b #$82,(A2)+ ; Means a polite request
move.b D1,(A2)+ ; nth block of this chunk follows
move.w gExpectHdr+2,(A2)+
move.l D0,(A2)+ ; first block of this chunk
lea gWDS,A2
clr.w (A2)+ ; WDS+0: reserved field
pea gAddr
move.l (SP)+,(A2)+ ; WDS+2: pointer to address struct
move.w #8,(A2)+ ; WDS: push length/ptr of header
pea gQuery
move.l (SP)+,(A2)+
move.w #512,(A2)+ ; WDS: push length/ptr of body
move.l $20(A0),D0 ; ptr = ioBuffer
add.l $28(A0),D0 ; + ioActCount
move.l D0,(A2)+
clr.w (A2)+ ; WDS: end with zero
move.l A0,-(SP)
lea gMyPB,A0
bsr DrvrClearBlock
pea DrvrDidSendWrite
move.l (SP)+,$C(A0) ; ioCompletion
move.w #-10,$18(A0) ; ioRefNum = .MPP
move.w #246,$1A(A0) ; csCode = writeDDP
move.b #10,$1C(A0) ; socket = 10 (hardcoded)
move.b #1,$1D(A0) ; set checksumFlag
pea gWDS
move.l (SP)+,$1E(A0) ; wdsPointer to our WriteDataStructure
dc.w $A404 ; _Control ,async
move.l (SP)+,A0
rts
DrvrDidSendWrite ; completion routine for the above control call..
; need to test whether to send another, or switch to wait mode...
move.l gMyDCE,A0
move.l 6+2(A0),A0 ; A3 = dCtlQHdr.qHead = ParamBlk
movem.l $24(A0),D0/D1 ; D0=ioReqCount, D1=ioActCount
add.l #512,D1
move.l D1,$28(A0)
cmp.l D0,D1
beq.s .sentAllOfChunk
and.l #(32-1)*512,D0
beq.s .sentAllOfChunk
bra DrvrSendWrite
.sentAllOfChunk
rts ; TODO: set up a timeout/retry task
DrvrClearBlock
move.w #$32/2-1,D0
.loop clr.w (A0)+
dbra D0,.loop
lea -$32(A0),A0
rts
DrvrSockListener
; Registers on call to DDP socket listener:
; A0 Reserved for internal use by the .MPP driver. You must preserve this register
; until after the ReadRest routine has completed execution.
; A1 Reserved for internal use by the .MPP driver. You must preserve this register
; until after the ReadRest routine has completed execution.
; A2 Pointer to the .MPP driver's local variables. Elliot says: the frame and packet
; header ("RHA") are at offset 1 from A2 (keeps the 2-byte fields aligned)
; A3 Pointer to the first byte in the RHA past the DDP header bytes (the first byte
; after the DDP protocol type field).
; A4 Pointer to the ReadPacket routine. The ReadRest routine starts 2 bytes after the
; start of the ReadPacket routine.
; A5 Free for your use before and until your socket listener calls the ReadRest routine.
; D0 Lower byte is the destination socket number of the packet.
; D1 Word indicating the number of bytes in the DDP packet left to be read (that is,
; the number of bytes following the DDP header).
; D2 Free for your use.
; D3 Free for your use.
; Registers on entry to the ReadPacket routine
; A3 Pointer to a buffer to hold the data you want to read
; D3 Number of bytes to read; must be nonzero
; Registers on exit from the ReadPacket routine
; A0 Unchanged
; A1 Unchanged
; A2 Unchanged
; A3 Address of the first byte after the last byte read into buffer
; A4 Unchanged
; D0 Changed
; D1 Number of bytes left to be read
; D2 Unchanged
; D3 Equals 0 if requested number of bytes were read, nonzero if error
; Registers on entry to the ReadRest routine
; A3 Pointer to a buffer to hold the data you want to read
; D3 Size of the buffer (word length); may be 0
; Registers on exit from the ReadRest routine
; A0 Unchanged
; A1 Unchanged
; A2 Unchanged
; A3 Pointer to first byte after the last byte read into buffer
; D0 Changed
; D1 Changed
; D2 Unchanged
; D3 Equals 0 if requested number of bytes exactly equaled the size of the buffer;
; less than 0 if more data was left than would fit in buffer (extra data equals
; -D3 bytes); greater than 0 if less data was left than the size of the buffer
; (extra buffer space equals D3 bytes)
; cmp.b #10,-1(A3) ; DDP protocol type better be ATBOOT
; bne.s DrvrTrashPacket
moveq.l #4,D3
jsr (A4) ; Read the nice short packet header
bne DrvrTrashPacket
move.l -4(A3),D2
move.l gExpectHdr,D3 ; Check the packet header
eor.l D2,D3
swap D3
clr.b D3
bne DrvrTrashPacket
btst #25,D2
bne.s DrvrDidReceiveWrite
DrvrDidReceiveRead
swap D2
and.l #32-1,D2 ; D2.L = block offset within 32blk chunk
move.l gMyDCE,A3
move.l 6+2(A3),A3 ; A3 = dCtlQHdr.qHead
move.l $28(A3),D3 ; D3 = .ioActCount...
lsr.l #5,D3
lsr.l #4,D3 ; ...now in number of blocks
and.l #-32,D3 ; ...rounded down to a block chunk
add.l D2,D3 ; ...added back the received block
asl.l #8,D3
add.l D3,D3 ; ... = byte offset within buffer
move.l $20(A3),A3 ; .ioBuffer
add.l D3,A3 ; A3 = ioBuffer + offset
move.l #512,D3 ; D3 = size
jsr 2(A4) ; ReadRest (A3=dest, D3=length)
bne DrvrTrashPacket
lea gProgress,A1 ; Skip the next step if this packet is a repeat
move.l (A1),D1
bset.l D2,D1 ; (we saved blkidx in D2 before ReadRest)
bne.s DrvrTrashPacket
move.l D1,(A1)
move.l gMyDCE,A0
move.l 6+2(A0),A0 ; dCtlQHdr.qHead
move.l $28(A0),D0 ; Increment ioActCount and cmp with ioReqCount
add.l #512,D0
move.l D0,$28(A0)
cmp.l $24(A0),D0
beq.s DrvrIODone
addq.l #1,D1 ; If bitmap=$FFFFFFFF then get the next chunk of 32
beq DrvrSendRead ; A0 must be the PB
rts ; Just return to await more packets.
DrvrDidReceiveWrite
moveq.l #0,D3
jsr 2(A4) ; ReadRest (D3=0 i.e. discard)
move.l gMyDCE,A0
move.l 6+2(A0),A0 ; A3 = dCtlQHdr.qHead = ParamBlk
movem.l $24(A0),D0/D1 ; D0=ioReqCount, D1=ioActCount
cmp.l D0,D1
blo DrvrSendWrite
bra.s DrvrIODone
DrvrIODone
lea gExpectHdr,A1 ; Disable this socket listener
clr.w (A1)
move.l gMyDCE,A1
moveq.l #0,D0
move.l $8FC,A0 ; jIODone (D0 = result, A1 = DCE)
jmp (A0)
DrvrTrashPacket
moveq.l #0,D3
jmp 2(A4) ; ReadRest nothing
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrControl
move.w #-17,$10(A0) ; ioResult = controlErr
bra DrvrFinish
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrStatus
cmp.w #6,$1A(A0)
beq.s status_fmtLstCode
cmp.w #8,$1A(A0)
beq.s status_drvStsCode
bra.s status_unknown
status_fmtLstCode ; tell them about our size
movem.l A2/A3,-(SP)
lea gNumBlks,A3
move.l (A3),D0
lsl.l #5,D0 ; convert from blocks to bytes
lsl.l #4,D0
move.w #1,$1C(A0)
move.l $1C+2(A0),A2
move.l D0,0(A2)
move.l #$40000000,4(A2)
movem.l (SP)+,A2/A3
move.w #0,$10(A0) ; ioResult = noErr
bra DrvrFinish
status_drvStsCode ; tell them about some of our flags
move.w #0,$1C(A0) ; csParam[0..1] = track no (0)
move.l #$00080000,$1C+2(A0) ; csParam[2..5] = same flags as dqe
move.w #0,$10(A0) ; ioResult = noErr
bra DrvrFinish
status_unknown
move.w $1A(A0),D0 ; dodgy, for debugging
add.w #$3000,D0
dc.w $A9C9
move.w #-18,$10(A0) ; ioResult
bra DrvrFinish
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrClose
move.w #$4444,D0
dc.w $A9C9
move.w #0,$10(A0) ; ioResult
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrFinish
move.w 6(A0),D1 ; iopb.ioTrap
btst #9,D1 ; noQueueBit
bne.s DrvrNoIoDone
move.l $8FC,-(SP) ; jIODone
DrvrNoIoDone
rts
DrvrEnd
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
HealInjuredBootBlocks ; patch the BBs to fix themselves if executed
; Args: A0 = truncated boot blocks (138b), A1 = correct boot blocks (1024b)
; If these boot blocks are executable (from offset 2), then the 138 bytes of
; declarative data copied by the netBOOT driver are not enough. We edit the boot
; blocks with a stub that copies the entire 1k into place. System 7 needs this.
; This unfortunately clobbers the declarative part of the boot blocks, so we need to
; check for declarative boot blocks and leave them unchanged
move.l A0,-(SP) ; Save A1 to a global, but need to keep A0
lea .gFullLoc,A0
move.l A1,(A0)
move.l (SP)+,A0
move.b 6(A0),D0 ; BBVersion
cmp.b #$44,D0
beq.s .executable
and.b #$C0,D0
cmp.b #$C0,D0
beq.s .executable
rts
; Relevant structure of the boot blocks:
; 0-1 bbID always 'LK'
; 2-5 bbEntry BRA.W base+128
; 6-7 bbVersion interpreted as above
; 8-137 data
; 138-1023 code (MISSING from netBOOT's short version)
; Our self-repairing boot blocks:
; 0-1 bbID always 'LK'
; 2-5 bbEntry BRA.W base+8
; 6-7 bbVersion interpreted as above
; 8-13 JSR .inPlaceFixRoutine
; 14-137 junk
.executable ; Need to leave bytes 6,7 intact
move.l #$60000004,2(A0) ; BB+2: BRA.W BB+8
move.w #$4EB9,8(A0) ; BB+8: JSR .inPlaceFixRoutine (abs)
lea .inPlaceFixRoutine,A1
move.l A1,10(A0)
move.l A0,A1 ; Clear the icache with a BlockMove
move.l #138,D0
dc.w $A02E ; _BlockMove
rts
.inPlaceFixRoutine ; The BB stub JSRs to here
move.l (SP)+,A1 ; so the return address will be at BB+14
lea -14(A1),A1 ; "Rewind" to the start of the BB
move.l .gFullLoc,A0 ; And here are our full boot blocks
move.l #1024,D0
dc.w $A02E ; _BlockMove (needs to clear cache)
jmp 2(A1) ; Jump to the fixed-up BB
.gFullLoc dc.l 0 ; Stuff addr of full-length BB in here
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
InstallInSysHeap
; takes A0/D0 as args, returns ptr in A0
movem.l A0/D0,-(SP)
dc.w $A51E ; NewPtr ,Sys
movem.l (SP)+,A1/D0 ; now A1=old, A0=new
exg A0,A1 ; now A1=new, A0=old
move.l D0,-(SP)
dc.w $A02E ; _BlockMove
move.l (SP)+,D0
exg A1,A0 ; now A1=old, A0=new
subq.l #1,D0
.wipeloop move.b $99,(A1)+
dbra D0,.wipeloop
rts
BootPicker include "BootPicker.a"
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