; I implement a "BootServer" on the AppleTalk network
; The Server Desk Accessory installs me in the system heap and opens me

ServerHeader
            dc.w    $4000           ; dNeedLock
            dc.w    0               ; delay
            dc.w    0               ; evt mask
            dc.w    0               ; menu

            dc.w    ServerOpen-ServerHeader
            dc.w    0               ; no Prime
            dc.w    0               ; no Control
            dc.w    0               ; no Status
            dc.w    ServerClose-ServerHeader
            dc.b    14, '.NetBootServer'
            even
            dc.b    0, 0, $20, 1    ; version

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Inline globals are practical because we are locked in the sysheap

ATBOOT_BLK_LOG      equ 8
ATBOOT_BLK_SIZE     equ 1<<ATBOOT_BLK_LOG

gNameTableEntry ; Installed using RegisterName
            dc.l    0               ; qLink
            dc.l    0               ; addrblock (our DDP skt at offset 7)
            odd
            dc.b    4, '0000'       ; object (must match const in PRAM)
            dc.b    10, 'BootServer'; type (always this)
            dc.b    1, '*'          ; zone
            even

gABPBusyFlag ; Lockout flag: only one ABP request can be serviced at a time
            dc.w    0

gABPReplyParamBlk ; For writeDDP control calls
            dcb.b   $32

gABPWriteDataStruct ; For writeDDP control calls (gathers buffers into one pkt)
            dcb.b   24 ; doesn't need to be this long at all

            odd
gABPAddress ; Address of the Apple Boot Protocol client:
            ; set when socket listener gets a packet, used when replying
            dcb.b   15              ; totally obscure address format
            dc.b    10              ; ddp type
            dcb.b   1               ; backup of high byte of dest network
                                    ; (MUST copy byte 16 to 7 for every use)

gABPUserReply ; reply to rbMapUser packet
            dc.b    2               ; rbUserReply
            dc.b    1               ; protocol version (always 1)
            dc.w    1               ; osID (always 1)
            dc.l    $FFFFFFFF       ; copy client's timestamp here (offset 4)
            dc.w    ATBOOT_BLK_SIZE ; block size
            dc.w    0               ; imageID (we always use 0)
            dc.w    0               ; error code
            dc.l    (BlobEnd-Blob)/ATBOOT_BLK_SIZE ; block count
            dcb.b   568             ; arbitrary bytes

gABPImageReply ; reply to rbImageRequest packet
            dc.b    4               ; rbImageData
            dc.b    1               ; protocol version (always 1)
            dc.w    0               ; imageID (we always use 0)
            dc.w    0               ; increment block number here (offset 4)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

ServerOpen
            movem.l A0/A1,-(SP)

; Try *once*. AT might come up later but not because of us.
            bsr     TryOpenMPP
            bne.s   .couldNotOpenAppleTalk
            bsr     Listen
.couldNotOpenAppleTalk

; Be ready for the LAP Manager to open/close .MPP
            bsr     RegisterForTransitions

            movem.l (SP)+,A0/A1
            clr.w   $10(A0)         ; return noErr
            rts

ServerClose
            movem.l A0/A1,-(SP)
            bsr     StopListening
            movem.l (SP)+,A0/A1
            clr.w   D0              ; return noErr
            rts

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

TryOpenMPP
; Checking whether the "B" printer port is configured for AppleTalk is an
; application responsibility on 64K ROM machines (as documented in IM),
; but 128K ROM and later machines move this check to AppleTalk itself,
; for example to allow other AppleTalk interfaces.
            tst.w   $28E            ; ROM85 positive?
            bgt.s   .returnYes      ; it is always safe to try on 128K machines

            move.b  $1FB,D0         ; SPConfig & 0xF == useFree (0) or useATalk (1)?
            and.b   #$F,D0
            sub.b   #1,D0
            ble.s   .returnYes

            move.b  $291,D0         ; PortBUse negative or useATalk (1)?
            blt.s   .returnYes
            cmp.b   #1,D0
            beq.s   .returnYes

.returnNo   moveq   #1,D0
            rts

.returnYes
            sub     #$32,SP
            lea     .MPP,A0
            move.l  A0,$12(SP)      ; IOFileName
            clr.b   $1B(SP)         ; IOPermssn
            move.l  SP,A0
            dc.w    $A000           ; _Open
            tst.w   $10(A0)         ; IOResult: check it
            add     #$32,SP
            rts

.MPP        dc.b    4, '.MPP', 0

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

RegisterForTransitions rts ; register for the LAP Manager queue if possible

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

Listen
            sub     #$32,SP         ; OPEN DDP SOCKET
            move.w  #-10,$18(SP)        ; ioRefNum = MPP
            move.w  #248,$1A(SP)        ; csCode = openSkt
            clr.b   $1C(SP)             ; socket = auto-assign
            pea     SocketListener
            move.l  (SP)+,$1E(SP)       ; listener
            move.l  SP,A0
            dc.w    $A004               ; _Control
            lea     gNameTableEntry+7,A0 ; lowest byte of AddrBlock
            move.b  $1C(SP),(A0)        ; save socket number there
            add     #$32,SP

            sub     #$32,SP         ; ADVERTISE NBP SERVICE
            move.w  #-10,$18(SP)        ; ioRefNum = MPP
            move.w  #253,$1A(SP)        ; csCode = registerName
            move.b  #7,$1C(SP)          ; interval = 7*8 ticks = 1sec
            move.b  #5,$1D(SP)          ; count = 5
            pea     gNameTableEntry
            move.l  (SP)+,$1E(SP)       ; entityPtr = our NTE
            move.b  #1,$22(SP)          ; verifyFlag = do
            move.l  SP,A0
            dc.w    $A004               ; _Control
            add     #$32,SP

            rts


StopListening
            sub     #$32,SP         ; REMOVE NBP SERVICE
            move.w  #-10,$18(SP)        ; ioRefNum = MPP
            move.w  #252,$1A(SP)        ; csCode = removeName
            pea     gNameTableEntry
            move.l  (SP)+,$1E(SP)       ; entityPtr = our NTE
            move.l  SP,A0
            dc.w    $A004               ; _Control
            add     #$32,SP

            sub     #$32,SP         ; CLOSE DDP SOCKET
            move.w  #-10,$18(SP)        ; ioRefNum = MPP
            move.w  257,$1A(SP)         ; csCode = closeSkt
            move.b  gNameTableEntry+7,$1C(SP); socket = auto-assign
            move.l  SP,A0
            dc.w    $A004               ; _Control
            add     #$32,SP

            rts

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

SocketListener ; Socket listener registers documented in IM
            lea     gABPBusyFlag,A5
            bset.b  #7,(A5)
            bne     .TrashPacketStayingBusy

            lea     gABPAddress,A5  ; RETURN ADDRESS SAVE CODE
            move.b  2(A2),11(A5)    ; both types node (ALAP header starts A2+1)
            move.b  -2(A3),13(A5)   ; both types socket (DDP header ends A3)
            moveq   #0,D3           ; short packet network = 0
            cmp.b   #1,3(A2)
            beq.s   .short
            move.w  10(A2),D3       ; long packet network
.short      move.w  D3,7(A5)        ; network number as usual
            asr.w   #8,D3
            move.b  D3,16(A5)       ; backup high-order byte of network number
                                    ; otherwise would go to offset 7

; Always get the command, version and two more bytes
            moveq   #8,D3
            jsr     2(A4)           ; ReadRest command, version and 6 more bytes
            ;bne.s   TrashPacket
            subq    #6,A3
            cmp.b   #1,-(A3)        ; version must be 1
            bne.s   .TrashPacket
            move.b  -(A3),D2
            subq.b  #1,D2
            beq.s   .rbMapUser      ; 1 = user record request
            subq.b  #2,D2           ; 3 = imageRequest
            beq.s   .rbImageRequest

.TrashPacket
            lea     gABPBusyFlag,A5
            clr.b   (A5)
.TrashPacketStayingBusy
            moveq   #0,D3
            jmp     2(A4)           ; ReadRest


.rbMapUser ; "user record request"
; +0 (1b)     command (already checked)
; +1 (1b)     version (already checked)
; +2 (2b)     osID (already slurped and ignored)
; +4 (4b)     userData (timestamp to be returned in reply)
; +8 (32b)    userName
            lea     gABPUserReply+4,A0
            move.l  4(A3),(A0)      ; copy "userData" to the reply

            lea     gABPWriteDataStruct+14,A1
            clr.w   -(A1)
            lea     gABPUserReply,A0
            move.l  A0,-(A1)
            move.w  #586,-(A1)
            lea     gABPAddress,A0
            move.l  A0,-(A1)
            clr.w   -(A1)

            move.b  16(A0),7(A0)    ; repair the address struct

            lea     gABPReplyParamBlk,A0
            move.l  A1,$1E(A0)      ; wdsPointer
            lea     AllDoneCompletionRoutine,A1
            move.l  A1,$C(A0)       ; ioCompletion
            move.w  #-10,$18(A0)    ; ioRefNum = .MPP
            move.w  #246,$1A(A0)    ; csCode = writeDDP
            move.b  gNameTableEntry+7,$1C(A0); our socket
            move.b  #1,$1D(A0)      ; set checksumFlag
            dc.w    $A404           ; _Control ,async
            rts

.rbImageRequest ; reply with rbImageReply
; +0 (1b)     command (already checked)
; +1 (1b)     version (already checked)
; +2 (2b)     imageID (already slurped and ignored)
; +4 (1b)     section, ie which 2MB chunk
; +5 (1b)     flags
; +6 (2b)     replyDelay
; +8 (<=512b) bitmap

; IGNORE the janky bitmap because the client implementation is buggy.
; It is reasonable just to send every packet instead (our image is tiny).

            lea     gABPImageReply+4,A0 ; count of packets to send
            move.w  #(BlobEnd-Blob)/ATBOOT_BLK_SIZE,(A0)

ImageReplyCompletionRoutine ; fallthru from skt listener OR writeDDP completion
            lea     gABPImageReply+4,A0
            move.w  (A0),D0
            subq.w  #1,D0
            move.w  D0,(A0)
            blt.s   AllDoneCompletionRoutine

            move.w  D0,D1 ; D0 = idx, D1 = offset
            mulu.w  #ATBOOT_BLK_SIZE,D1

            lea     gABPWriteDataStruct+20,A1
            clr.w   -(A1)

            lea     Blob,A0
            lea     (A0,D1),A0
            move.l  A0,-(A1)
            move.w  #ATBOOT_BLK_SIZE,-(A1)

            lea     gABPImageReply,A0
            move.w  D0,4(A0)
            move.l  A0,-(A1)
            move.w  #6,-(A1)

            lea     gABPAddress,A0
            move.l  A0,-(A1)
            clr.w   -(A1)

            move.b  16(A0),7(A0)    ; repair the address struct

            lea     gABPReplyParamBlk,A0
            move.l  A1,$1E(A0)      ; wdsPointer
            lea     ImageReplyCompletionRoutine,A1
            move.l  A1,$C(A0)       ; ioCompletion
            move.w  #-10,$18(A0)    ; ioRefNum = .MPP
            move.w  #246,$1A(A0)    ; csCode = writeDDP
            move.b  gNameTableEntry+7,$1C(A0); our socket
            move.b  #1,$1D(A0)      ; set checksumFlag
            dc.w    $A404           ; _Control ,async
            rts


AllDoneCompletionRoutine
            lea     gABPBusyFlag,A0
            clr.b   (A0)
            rts

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

Blob
            incbin  'Client.bin.summed' ; built from Client.a
BlobEnd