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mac-rom/OS/SCSIMgr/SCSIMgrHWPSC.a
Elliot Nunn 4325cdcc78 Bring in CubeE sources 
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;
; File: SCSIMgrHWPSC.a
;
; Contains: SCSI Manager 53c96 Hardware-Specific routines
;
; Written by: Jonathan Abilay/Paul Wolf
;
; Copyright: © 1990-1993 by Apple Computer, Inc. All rights reserved.
;
; Change History (most recent first):
;
; <SM11> 8/12/93 KW conditionalizing smurf branches
; <SM10> 8/11/93 KW added some branches based on new smurf boxes
; <SM9> 12/23/92 RC Added Support for Smurf on Wombat
; <SM8> 12/3/92 fau Added boxRiscQuadra to the previous DAFBExists change.
; <SM7> 12/3/92 fau Changed the use of DAFBExists to check for the
; Spike/Eclipse/Zydeco box flag. Those registers on DAFB are only
; needed on those machines. Changed the check for BoxCyclone to a
; TestFor PSCExists (this assumes that only Cyclone type machines
; have a PSC).
; <SM6> 11/3/92 SWC Changed SCSIEqu.a->SCSI.a.
; <SM5> 8/24/92 PN Take out CycloneboxEVT1 stuff
; <SM4> 8/9/92 CCH Modified boxflag check for Quadras to include RISC Quadras.
; <SM3> 6/21/92 RB Also check for BoxCycloneEVT1 to select the right SCSI, this is
; temporary while we need to support EVT1 units.
; <SM2> 6/2/92 CS Move Hack from <SM0> so that it will assemble.
; <1> 6/2/92 kc first checked in
; <SM0> 6/01/92 kc Rolled in from Pandora. (Hacked out DAFB stuff)
; <P2> 1/28/92 PW Added Cyclone to initialization of SCSI clock-dependent
; registers.
; <P1> 1/17/92 PDW first checked in
; ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ
; Pre-Pandora ROM comments begin here.
; ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ
; <4> 9/4/91 SAM (PDW) Fixed polled write PhaseErr bug by using status register
; for phase test instead of bogus D5 register.
; <3> 8/21/91 SAM (PDW) Removed bunch of debugging stuff. Removed "fix" for VM_On
; BEH problem since "real" fix is now in dataCommon_96
; (SCSIMgr96.a).
; <2> 8/19/91 SAM (PDW) Reverted to old in/out buserr handler support. Fixed
; incorrect loop counting in BusErrHandler (wasn't taking zero
; case into account). Increased quanta of DREQ timeout value
; in BEH (twice as long). Changed Transfer so that we don't modify
; yeOldeBusErrVct if vector at 8 is already our SCSI bus error
; handler. This fixes "symptom" of VM_On/BEHandler Vector bug.
; <1> 8/8/91 SAM (PDW) Checked into Regatta for the first time with lots of
; changes over the TERROR sources.
; <0> 8/8/91 SAM Split off from TERROR sources.
;
; Pre Regatta split-off change history:
;
; <T10> 7/8/91 djw (pdw) Fixed bug in FastRead_96 and FastComp_96 where any odd
; count over 256 bytes would fail (cmp.b should be a cmp.l).
; <T9> 6/27/91 BG (actually PDW/CCH/BG) changed the dynamic register setup stuff
; in InitSCSICyc96HW so that the ProductInfo record is where the
; information for the BoxFlag check comes from.
; <T8> 6/27/91 djw (actually PDW) Changes for better handling of select sequence
; across phases and across traps. Added NOPs at top and bottom of
; non-serialized accesses to squish pipeline (to avoid problems at
; higher CPU speeds. Fixed SlowRead hang (when phase changes
; before transfer is complete (scInc or scNoInc). Fixed FastRead
; residual byte problem (where we didn't detect the missing REQ)
; by checking the FIFO count before doing the rFFO. Also removed
; all traces of SCSIBusy and FreeHook stuff. Made BusErrHandler
; able to deal with no valid registers. (JMA) Added BusErrHandler
; routine.
; <T7> 6/14/91 djw (actually PDW) Created working Transfer_96 routine that sends
; ptr to non-serialized chip image to data routines. Also modified
; all data routines to use this for all rDMA register accesses.
; Put FCIntPend clear in WaitForSCSIIntrp_PSC (w & w/o timeout) so
; that every time the interrupt bit in the chip was cleared, this
; select_in_progress flag is cleared also.
; <T6> 6/9/91 BG (BG) InitHW_SCSI_PSC: Reworked the routine to handle dynamic
; initialization of DAFB/Turbo SCSI register based on CPU clock
; speed. Modified check for SCSI clk speed initialization for
; Eclipse and Spike to (1) be based on D2 instead of BoxFlag,
; since BoxFlag has not been initialized yet when this routine is
; called, and (2) added dynamic initialization of 16/25MHz SCSI
; clk speed based on CPU clk speed. (PDW) Changed throwaway reg
; at end. Rearranged headers to work more consistently between
; test INIT and ROM builds.
; <T5> 3/30/91 BG (actually JMA) Rolled in faster SlowRead_96 and SlowComp_96
; routines.
; <T4> 2/17/91 BG (actually JMA) Added SlowComp_96, FastComp_96 & Error calls.
; <T3> 1/11/91 BG Added fix to correctly reset SCSI 96 bus.
; <T2> 1/5/91 BG (actually JMA) Added functionalites.
; <T1> 12/7/90 JMA Checked into TERROR for the first time
;
;========================================================================== <T4>
MACHINE MC68020 ; '020-level
BLANKS ON ; assembler accepts spaces & tabs in operand field
STRING ASIS ; generate string as specified
PRINT OFF ; do not send subsequent lines to the listing file
; don't print includes
PostNOP EQU 1 ; <T8>
LOAD 'StandardEqu.d' ; from StandardEqu.a and for building ROMs
INCLUDE 'HardwarePrivateEqu.a'
INCLUDE 'UniversalEqu.a' ; for VIA bit and -TestFor- definitions <T6>
INCLUDE 'SCSI.a'
INCLUDE 'SCSIPriv.a'
INCLUDE 'SCSIEqu96.a'
INCLUDE 'MC680x0.a'
PRINT ON ; do send subsequent lines to the listing files
SCSICycHW96 PROC EXPORT
EXPORT SlowRead_PSC, Transfer_PSC, Xfer1Byte_PSC
EXPORT Wt4DREQorIntPSC,HandleSelInProgPSC
EXPORT ResetBus_PSC, WaitForSCSIIntrp_PSC
EXPORT BusErrHandler_PSC ; <T8>
EXPORT InitHW_SCSI_PSC,IntHnd_SCSI_PSC
EXPORT SlowWrite_PSC, SlowComp_PSC ; <T4>
EXPORT FastRead_PSC, FastWrite_PSC, FastComp_PSC ; <T4>
IMPORT ClearSCSIInt ; from InterruptHandlers.a <T4>
IMPORT SCSIpcTo32Bit_PSC, Error_PSC, SwapMMU ; from SCSIMgr96.a <T4>
EXPORT WaitForIntNoTime_PSC
WITH scsiPB, scsiPrivPB ; access record without explicit qualification
WITH scsiGlobalRecord, dcInstr
;--------------------------------------------------------------------------
;
; InitHW_SCSI_PSC - reset and initialize the 53C96 SCSI controller
; This routine resets all functions in the chip and returns
; it to a disconnected state.
;
; INPUTS
; a3 -> pointer to SCSI port base address <T6>
; a4 -> pointer to SCSI DAFB register <T6>
; (NOTE - this routine assumes that we are in 32-bit mode!) <T6>
; d2 -> 16/HWCfgFlags, 8/BoxFlag, 8/MemDecoder <T6>
; (the lowMem BoxFlag is not yet defined!) <T6>
;
; OUTPUTS
; d0 <- rINT(a3) <T6>
;
; trashes: d0, d1, a0 <T6>
InitHW_SCSI_PSC
move.b #cRstSChp, rCMD(a3) ; load reset-scsi-chip cmd, this cmd has
; the same effect as a hw reset
move.b #cNOP, rCMD(a3) ; NOP required after HW or SW reset
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO
move.b #initCF1, rCF1(a3) ; load init config. value which affects:
; busID, SCSI reset reporting & parity checking
move.b #initCF2, rCF2(a3) ; load init config. value
move.b #initCF3, rCF3(a3) ; load init config. value
; Check whether or not we're 25 or 33MHz and set SCSI bus speed values appropriately <T6> thru next <T6>
TestFor VIA2Exists ; see if we should check 25/33MHz VIA2 bit
beq.s @setupC96 ; if there's not a VIA2, don't do it.
; Change to check for BoxFlags for Spike/Eclipse/Zydeco, instead of DAFBExists, since this
; special stuff only applies to those 3 machines. <SM7>
move.l UnivInfoPtr,A0 ; get pointer to universal table
cmp.b #BoxQuadra700,ProductInfo.ProductKind(A0) ; check for a Spike
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco
cmp.b #BoxQuadra900,ProductInfo.ProductKind(A0) ; check for a Eclipse
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco
cmp.b #BoxQuadra950,ProductInfo.ProductKind(A0) ; check for a Zydeco
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco
IF forSmurf THEN
cmp.b #boxRiscQuadra700,ProductInfo.ProductKind(A0) ; check for a RISC Quadra700 <SM10>
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco <SM10>
cmp.b #boxRiscQuadra900,ProductInfo.ProductKind(A0) ; check for a RISC Quadra900 <SM10>
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco <SM10>
cmp.b #boxRiscQuadra950,ProductInfo.ProductKind(A0) ; check for a RISC Quadra950 <SM10>
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco <SM10>
cmp.b #boxRiscCentris610,ProductInfo.ProductKind(A0) ; check for a RISC Quadra610 <SM10>
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco <SM10>
cmp.b #boxRiscCentris650,ProductInfo.ProductKind(A0) ; check for a RISC Quadra650 <SM10>
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco <SM10>
cmp.b #boxRiscQuadra800,ProductInfo.ProductKind(A0) ; check for a RISC Quadra800 <SM10>
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco <SM10>
cmp.b #boxRiscQuadra610,ProductInfo.ProductKind(A0) ; check for a RISC Quadra610 <SM11>
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco <SM11>
cmp.b #boxRiscQuadra650,ProductInfo.ProductKind(A0) ; check for a RISC Quadra650 <SM11>
beq.s @DoSpikeEclipseZydeco ; Special setup for Spike/Eclipse/Zydeco <SM11>
ENDIF ; for smurf
bra.s @setupC96 ; only Spike/Eclipse have a VIA2 and DAFB
@DoSpikeEclipseZydeco
move.l VIA2,a0 ; and get VIA2 so that we can check the speed bit
move.b vBufB(a0),d0 ; read PBx values for 25/33MHz checks
btst #v2Speed,d0 ; are we 25 MHz or 33 Mhz?
beq.s @25MHz ; IF Speed == 33MHz THEN
move.l #tsc_cf_stg_33,(a4) ; setup DAFB SCSI config register.
; ... must move 32 bits to DAFB
bra.s @setupC96 ; ELSE // Speed == 25MHz
@25MHz
move.l #tsc_cf_stg_25,(a4) ; setup DAFB SCSI config register.
; ... must move 32 bits to DAFB
; ENDIF
@setupC96
;******* Need to work with Spike, Eclipse, Zydeco or Cyclone ***** <P2> thru next <P2>
;
; CPU SCSI
; Quadra700 25 25
; Quadra900 25 15.6672
; Zydeco 33 24.28416 (boxFlag=Eclipse)
; Cyclone 33 25 or 24.576 (which?)
move.l UnivInfoPtr,A0 ; get pointer to universal table <T9>
cmp.b #BoxQuadra700,ProductInfo.ProductKind(A0) ; check for a Spike <T9>
beq.s @ForSpike ; (note - BoxFlag is not defined at this point in boot) <T9>
IF forSmurf THEN
cmp.b #boxRiscQuadra700,ProductInfo.ProductKind(A0) ; check for a RISC Card in Quadra700 <SM10>
beq.s @ForSpike ; (note - BoxFlag is not defined at this point in boot) <SM10>
cmp.b #boxRiscCentris610,ProductInfo.ProductKind(A0) ; check for a RISC Card in Centris610 <SM10>
beq.s @ForSpike ; (note - BoxFlag is not defined at this point in boot) <SM10>
cmp.b #boxRiscCentris650,ProductInfo.ProductKind(A0) ; check for a RISC Card in a Centris650 <SM10>
beq.s @ForSpike ; (note - BoxFlag is not defined at this point in boot) <SM10>
cmp.b #boxRiscQuadra800,ProductInfo.ProductKind(A0) ; check for a RISC Card in a Quadra800 <SM10>
beq.s @ForSpike ; (note - BoxFlag is not defined at this point in boot) <SM10>
cmp.b #boxRiscQuadra610,ProductInfo.ProductKind(A0) ; check for a RISC Card in a Quadra610 <SM11>
beq.s @ForSpike ; (note - BoxFlag is not defined at this point in boot) <SM11>
cmp.b #boxRiscQuadra650,ProductInfo.ProductKind(A0) ; check for a RISC Card in a Quadra650 <SM11>
beq.s @ForSpike ; (note - BoxFlag is not defined at this point in boot) <SM11>
ENDIF ; for smurf
TestFor PSCExists ; Do we have a PSC?
bne.s @ForCyclone ; Yes, we do
; Either Eclipse or Zydeco, Check for difference between 25 and 33MHz: <T6>
btst #v2Speed,d0 ; are we running at 25 or 33 MHZ? <T6>
bne.s @ForZydeco ; IF Speed == 25MHz THEN <T6>
; Set up for a 16MHz (more or less) SCSI clock
@ForEclipse
move.b #ccf15to20MHz, rCKF(a3) ; load clock conversion factor (CCF) value
move.b #SelTO16Mhz, rSTO(a3) ; load select/reselect timeout value
bra.s @1 ; <T6>
; Set up for a 25MHz (more or less) SCSI clock
@ForZydeco ; ELSE // Speed == 33MHz <T6>
@ForSpike
@ForCyclone ; <P2> from prev <P2>
move.b #ccf20to25MHz, rCKF(a3) ; load clock conversion factor (CCF) value
move.b #SelTO25Mhz, rSTO(a3) ; load select/reselect timeout value
@1
move.b #initOp, rSYO(a3) ; select sync or async operation; if sync then
; sync offset value must be nonzero
; Set synch xfer period and offset if using
; synch data xfer
move.b rINT(a3), d0 ; read & clear rFOS, rSTA & rINT into throwaway <T6>
rts
;--------------------------------------------------------------------------
;
; IntHnd_SCSI_PSC - This is the SCSICyc96 interrupt handler
; Called by: Macintosh Interrupt Dispatcher
;
; Regrs saved: a0-a5/d0-d7
;
IntHnd_SCSI_PSC
movem.l intrRegs, -(sp) ; save registers
movea.l SCSIGlobals, a4 ; get ptr to structure
clr.l d5 ;
addq.l #1, G_IntrpCount(a4) ; count intrps - FOR Debug
move.l base539x0(a4), a3 ; load ptr for SBus0 <T2>
btst.b #bINT, rSTA(a3) ; test intrp bit of status regr
bne.s @gotSCSIInt ; bra. if we got SCSI intrp
@chkNext
move.l base539x1(a4), a3 ; load ptr for SBus1 <T2>
btst.b #bINT, rSTA(a3) ; test intrp bit of status regr
beq.s @ExitSCSIIntrp
@gotSCSIInt ;
; addq.l #1, G_base5396(a4) ; incr. valid SCSI intrp counter, for debug <T2>
move.b rSTA(a3), d5 ; read Status regr
swap d5 ;
move.b rFOS(a3), d5 ; read FIFO flag/Sequence Step regr
lsl.w #8, d5 ; shift left by 1 byte
move.b rINT(a3), d5 ; read & clear rFOS, rSTA & rINT
swap d5 ; d5 = rFOS|rINT|0|rSTA
move.l d5, G_IntrpStat(a4) ; save regr values, for debug <T2>
@ExitSCSIIntrp
movem.l (sp)+, intrRegs ; restore registers
rts ;
;--------------------------------------------------------------------------
; Transfer_PSC - <T7> thru next <T7>
;
; Called by: dataCommon_PSC
; (NewSCSIWBlind_PSC, NewSCSIWrite_PSC, NewSCSIRBlind_PSC, NewSCSIRead_PSC)
;
; Calls: The primitive data transfer routines
;
; Registers: d0 <-- error, if any
; d1 <-- bytes transferred
; d2 --> number of bytes to transfer
; d4 --> type of transfer to perform (offset into "dataTable")
;
; a2 --> ptr to data buffer
; a3 --> SCSI chip read base address - SERIALIZED
; a4 --> ptr to SCSI Mgr globals
;
; Function: Sets up and dispatches to the simple data-transfer routines
;
; All primitive data transfer routines called by this routine assume:
;
; d0 - <-- error (if any)
; d1 - <-- bytes transferred
; d2 - --> number of bytes to transfer
; d3 - scratch - saved
; d4 - --> type of transfer to perform
; d5 - scratch - saved
; d6 - scratch - saved
;
; a0 - scratch - saved
; a1 - SCSI chip read base address - NON-SERIALIZED
; a2 - ptr to data buffer - saved
; a3 - SCSI chip read base address - SERIALIZED
; a4 - ptr to SCSI Mgr globals
; a5 - scratch - saved
;
;
; Stack frame definitions (frame allocated in StdEntry)
;
XferFrame RECORD {LINK},DECR
returnAddr ds.l 1 ; return address
; no parameters
LINK ds.l 1 ; location of old A6 (after LINK A6)
; local variables (set up and checked in BusErrHandler)
BusErrTO ds.l 1 ; when to stop retrying bus errs
BusErrAddr ds.l 1 ; user's data address when bus err happens
linkSize EQU *
ENDR
WITH XferFrame
Transfer_PSC:
link a6, #linkSize ; allocate local storage
moveq #MaxBusErr,d0 ; upper limit for 680x0's
cmp.b #cpu68040,CpuFlag ; check if we're on an 040
bne.s @storeValue ; NO ... leave BusErrCount alone
moveq #Max040BusErrs,d0 ; YES ... use 040 MaxBusErr value
@storeValue ;
move.l #0, BusErrAddr(a6) ; init so first bus err is seen as a new one
moveq.l #noErr, d0 ; assume no error
move.l d2, d1 ; make a copy of the count - is it zero ?
beq.w @exit ; if so, get out
movem.l a1-a5/d2-d6, -(sp) ; save registers
movea.l a3,a1 ; point to serialized chip image
adda.l #nonSerlzdDisp,a1 ; point to non-serialized chip image
btst.b #OurBus, G_State96(a4) ; is c96 initiator on bus?
beq.s @phaseErr ; no - then we've got a phase error
bsr HandleSelInProgPSC ; handle unfinished select command
bne.w @phaseErr ; if it is stuck, we are not in data phase
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T8>
; move.l BusErrVct, D0 ; compare old vector (at 8) <2> <3>removed
; cmp.l jvBusErr(a4), D0 ; with my vector <2> <3>
; beq.s @1 ; if same, skip the install process <2> <3>
move.l BusErrVct,yeOldeBusErrVct(a4) ; keep old vector in low-mem <T8>
move.l jvBusErr(a4), BusErrVct ; install our BE Handler
@1
bset.b #HandleBusErrs, G_State96(a4) ; signal our bus err handler to be operative
move.w d4, transferType(a4) ; store the type of transfer (only word is worth anything)
lea.l dataTable(a4), a0 ; point to data transfer table in globals
movea.l 0(a0,d4.l), a0 ; get the routine address
jsr (a0) ; go to the appropriate routine
@done
bclr.b #HandleBusErrs, G_State96(a4) ; signal our bus err handler to be unoperative
move.l yeOldeBusErrVct(a4),BusErrVct ; restore previous Bus Error vector <T8><2>
movem.l (sp)+, a1-a5/d2-d6 ; restore these guys
tst.w d0 ; set the condition codes
@exit
unlk a6 ; release local storage
rts ; <T7> from last <T7>
@phaseErr
moveq.l #scPhaseErr, d0 ; return a phase error
moveq.l #0, d1 ; number of bytes transferred
bra.s @done ;
ENDWITH
;--------------------------------------------------------------------------
; OneByteRead/OneByteWrite - proc to transfer 1 byte <T2>
;
; d0 - <-- error (if any)
; d1 - --> copy of d2
; d1 - <-- bytes transferred
; d2 - --> number of bytes to transfer
; d3 - scratch - saved
; d4 - --> type of transfer to perform
; d5 - scratch - saved
; d6 - scratch - saved
;
; a0 - scratch - saved
; a1 - SCSI chip read base address - NON-SERIALIZED
; a2 - ptr to data buffer - saved
; a3 - SCSI chip read base address - SERIALIZED
; a4 - ptr to SCSI Mgr globals
; a5 - scratch - saved
OneByteRead ; <T2> thru next <T2>
move.b #cIOXfer, rCMD(a3) ; load IO transfer cmd & begin xfers
jsr.w WaitForIntNoTime_PSC ; Wait for intrp w/o timeout
; on exit d5 = rFOS|rINT|0|rSTA
bne.s xferErr ; bra. on xfer error
move.b rFFO(a3), (a2)+ ; xfer byte from FIFO into input buffer <T4> thru next <T4>
move.b rINT(a3), d3 ; read Intrp regr & clear rSTA, rSQS & rINT
btst.l #bDSC, d3 ; check for disconnected intrp
bne.s xferErr ; bra. on xfer error
moveq.l #noErr, d0 ; successful read op <T4>
rts
OneByteWrite
move.b (a2)+, rFFO(a3) ; preload the FIFO
move.b #cIOXfer, rCMD(a3) ; load IO transfer cmd & begin xfers
jsr.w WaitForIntNoTime_PSC ; Wait for intrp w/o timeout
; on exit d5 = rFOS|rINT|0|rSTA
bne.s xferErr ; bra. on xfer error
moveq.l #noErr, d0 ; successful write op
rts
xferErr
move.l #$F0, d6 ; load proc ID, generic transfer <T4> thru next <T4>
moveq.l #scCommErr, d0 ; transfer error
bra.s errExit
phaseErr1
move.l #$F0, d6 ; load proc ID, generic trnasfer
moveq.l #scPhaseErr, d0 ; return a phase error
errExit
jsr Error_PSC ; call Error proc - for debug
clr.l d1 ; no bytes transferred
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO
rts ; <T4>
;--------------------------------------------------------------------------
; Xfer1Byte_PSC - proc to transfer 1 byte of data
;
; Branched to by SlowRead/SlowWrite(Polled) & FastRead/SlowWrite(Blind). It returns directly
; Transfer proc which call either SlowRead or FastRead.
;
; d0 - <-- error (if any)
; d1 - --> copy of d2
; d1 - <-- bytes transferred
; d2 - --> number of bytes to transfer
; d3 - scratch - saved
; d4 - --> type of transfer to perform
; d5 - scratch - saved
; d6 - scratch - saved
;
; a0 - scratch - saved
; a1 - SCSI chip read base address - NON-SERIALIZED
; a2 - ptr to data buffer - saved
; a3 - SCSI chip read base address - SERIALIZED
; a4 - ptr to SCSI Mgr globals
; a5 - scratch - saved
Xfer1Byte_PSC
move.b #cIOXfer, rCMD(a3) ; load IO transfer cmd & begin xfers
jsr.w WaitForIntNoTime_PSC ; Wait for intrp w/o timeout
; on exit d5 = rFOS|rINT|0|rSTA
rts ; IF z=1 then good xfer...
;--------------------------------------------------------------------------
; SlowRead - implements Polled Read <T2>
;
; Called by: Transfer
;
; All primitive data transfer routines assume:
;
; Inputs --->
; -> D2.L number of bytes to transfer
; -> D1.L copy of d2
; -> A1 SCSI chip read base address - NON-SERIALIZED
; -> A2 ptr to data buffer - saved
; -> A3 SCSI chip read base address - SERIALIZED
; -> A4 ptr to SCSI Mgr globals
;
; Outputs <---
; <- D0.W error (if any)
; <- D1.L bytes transferred
; <- D5.L xxxx|xxxx|xxxx|rSTA
; <- D3 scratch - saved
; <- D4
; <- D6 scratch - saved
;
; Internal ---
; A0 - scratch - saved
; A1 - SCSI chip read base address - NON-SERIALIZED
; A2 - ptr to data buffer - saved
; A3 - SCSI chip read base address - SERIALIZED
; A4 - ptr to SCSI Mgr globals
; A5 - scratch - saved
;
; Method of Data Transfer: (pDMA and programmed IO) <T5> to next <T5>
; 0) Make sure we got our intrp from the last cmd send
; 1) calculate # of 16-byte block transfers to perform using pDMA & remember the remainder
; 2) Enable c96 DMA and wait till the 16-byte FIFO is full and DREQ is asserted for the 17th byte
; 3) Transfer all data in the FIFO and wait for the intrp
; 4) Repeat until all block have been transferred
; 5) Transfer remaining data using non-DMA transfer command byte then
; Wait and poll for byte-in-fifo interrupt
; 6) Transfer data from fifo to input buffer
; 7) Repeat process until all remaining bytes have been transferred
;
GEEZ EQU 0
SlowRead_PSC
bsr HandleSelInProgPSC ; handle unfinished select command
bne.w @phaseErr ; if it is stuck, we are not in data phase
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T8>
move.l d2, d3 ; d6 = number of 64KB blocks to perform
swap d3 ; d3.w:d2.w = total#bytes to xfer
bra.s @LpReadBtm
@LpReadTop
moveq.l #iPhaseMsk, d0 ; load mask for phase bits <T4> thru next <T4>
and.b rSTA(a3), d0 ; are we in data-in phase?
cmpi.b #iDataIn, d0 ; data-in phase bits = 001
bne.w phaseErr1 ; bra. on phase err
move.b #cIOXfer, rCMD(a3) ; load non-DMA transfer cmd & begin 1 byte xfer
bsr.w WaitForIntNoTime_PSC ; Wait for intrp w/o timeout
bne.s @xferErr ; bra. if xfer err
move.b rFFO(a3), (a2)+ ; do a byte
@LpReadBtm
dbra d2, @LpReadTop ; d2 = low word of count
dbra d3, @LpReadTop ; d3 = high word of count
@goodFRead ; d1 = # of bytes transferred
moveq.l #noErr, d0 ; successful read op
rts ;
@timedOut ; <T8>
moveq.l #scBusTOErr, d0 ; if we timed out, return error <T8>
bra.s @bytesXferd ; <T8>
@phaseErr
moveq.l #scPhaseErr, d0 ; return a phase error
bra.s @bytesXferd ; <T4>
@xferErr
moveq.l #scCommErr, d0 ; comm error
@bytesXferd ; <T4>
swap d3 ; calculate bytes left to transfer
move.w d2, d3 ; get low order word
sub.l d3, d1 ; d1 = xfer count - bytes remaining to xfer <T4> thru next <T4>
@badFRead
move.l #0, G_FakeStat(a4) ; Return a fake status
move.l #scsiRBlind, d6 ; load proc ID
jsr Error_PSC ; call Error proc - for debug
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T4>
rts ;
;--------------------------------------------------------------------------
; SlowWrite - implements Polled Write
;
; Called by: Transfer
;
; All primitive data transfer routines assume:
;
; d0 - <-- error (if any)
; d1 - --> copy of d2
; d1 - <-- bytes transferred
; d2 - --> number of bytes to transfer
; d3 - scratch - saved
; d4 - --> type of transfer to perform
; d5 - scratch - saved
; d6 - scratch - saved
;
; a0 - scratch - saved
; a1 - SCSI chip read base address - NON-SERIALIZED
; a2 - ptr to data buffer - saved
; a3 - SCSI chip read base address - SERIALIZED
; a4 - ptr to SCSI Mgr globals
; a5 - scratch - saved <T2>
;
; Method of Data Transfer: (uses pseudo-DMA mode)
; 0) Make sure we got our intrp from the last cmd send
; 1) Parcel transfer into 64KB blocks since TC regr. handles 64KB max
; 2) Calc. the number of 16-byte block transfers to perform
; 3) Calc. the remaining number of transfers to perform
; 4) Write data 16-byte blocks at a time using word MOVEs
; 5) Wait without timeouts until FIFO is empty ie. 16-byte transfer completed
; 6) Transfer residual byte if there is one
;
SlowWrite_PSC
; _debugger
bsr HandleSelInProgPSC ; handle unfinished select command
bne.w @phaseErr ; if it is stuck, we are not in data phase
@doWrite
move.l d2, d3 ; d6 = number of 64KB blocks to perform
swap d3 ; d3.w:d2.w = total#bytes to xfer
bra.s @LpWriteBtm
@LpWriteTop
moveq.l #iPhaseMsk, d0 ; load mask for phase bits <T4> thru next <T4>
and.b rSTA(a3), d0 ; are we in data-in phase?
;; cmpi.b #iDataOut, d0 ; data-in phase bits = 001
bne.w phaseErr1 ; bra. on phase err
move.b (a2)+, rFFO(a3) ; write a byte
move.b #cIOXfer, rCMD(a3) ; load non-DMA transfer cmd & begin 1 byte xfer
bsr.w WaitForIntNoTime_PSC ; Wait for intrp w/o timeout
bne.s @xferErr ; bra. if xfer err
@LpWriteBtm
dbra d2, @LpWriteTop ; d2 = low word of count
dbra d3, @LpWriteTop ; d3 = high word of count
@good ; d1 = # of bytes transferred
moveq.l #noErr, d0 ; successful read op
rts ;
@timedOut ; <T8>
moveq.l #scBusTOErr, d0 ; if we timed out, return error <T8>
bra.s @bytesXferd ; <T8>
@phaseErr
moveq.l #scPhaseErr, d0 ; return a phase error
bra.s @bytesXferd ; <T4>
@xferErr
moveq.l #scCommErr, d0 ; comm error
@bytesXferd ; <T4>
swap d3 ; calculate bytes left to transfer
move.w d2, d3 ; get low order word
sub.l d3, d1 ; d1 = xfer count - bytes remaining to xfer <T4> thru next <T4>
@badSWrite
move.l #0, G_FakeStat(a4) ; Return a fake status
move.l #scsiRBlind, d6 ; load proc ID
jsr Error_PSC ; call Error proc - for debug
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T4>
rts ;
;--------------------------------------------------------------------------
; FastWrite - implements Blind Write
;
; Called by: Transfer
;
; All primitive data transfer routines assume:
;
; d0 - <-- error (if any)
; d1 - --> copy of d2
; d1 - <-- bytes transferred
; d2 - --> number of bytes to transfer
; d3 - scratch - saved
; d4 - --> type of transfer to perform
; d5 - scratch - saved
; d6 - scratch - saved
;
; a0 - scratch - saved
; a1 - SCSI chip read base address - NON-SERIALIZED
; a2 - ptr to data buffer - saved
; a3 - SCSI chip read base address - SERIALIZED
; a4 - ptr to SCSI Mgr globals
; a5 - scratch - saved
;
; Method of Data Transfer: (uses pseudo-DMA mode)
; 0) Make sure we got our intrp from the last cmd send
; 1) Parcel transfer into 64KB blocks since TC regr. handles 64KB max
; 2) Preload FIFO with non-aligned byte; get us word aligned
; 3) Calc. the number of 32-byte block transfers to perform
; 4) Calc. the remaining number of transfers to perform
; 5) Write data 32-byte blocks at a time using word MOVEs
; 6) Write remaining data using word MOVEs
; 7) Transfer residual byte if there is one
FastWrite_PSC
bsr HandleSelInProgPSC ; handle unfinished select command
bne.w @phaseErr ; if it is stuck, we are not in data phase
@doWrite
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T8>
moveq.l #iPhaseMsk, d0 ;
and.b rSTA(a3), d0 ; are we in data-out phase?
bne.w phaseErr1 ; data-out phase bits = 0, bra. on phase err <T4> thru next <T4>
cmpi.l #1, d2 ; if 1 byte write then...
beq.w OneByteWrite ; ...do 1 byte transfer
move.l d2, d6 ; d6 = number 64KB block to perform
swap d6 ; upper word of d6 = lower word of d2
andi.l #$0000FFFF, d2 ; mask out upper word
beq @2 ; if 0 then we have $10000 (64K) bytes to xfer
move.l a2, d5 ;
btst.l #0, d5 ; check if input buffer is on word boundary
bne.w @misAligned
@next64KB ; buffer is aligned from this point <T4> thru next <T4>
move.l d2, d4 ; d4 <- d2
move.b d4, rXCL(a3) ; TC regr (least-sig. byte) <- d4.b
lsr.l #8, d4 ; get upper byte of low word
move.b d4, rXCM(a3) ; TC regr (most-sig. byte) <- d4.b
move.b #cDMAXfer, rCMD(a3) ; load DMA transfer cmd & begin xfers
; DREQ* should be active at this time
move.w d2, d4 ; d4 = copy of transfer count
lsr.w #5, d4 ; divide xfer count by 32
ror.l #1, d2 ; xfer byte count to word & remember odd byte
and.w #$F, d2 ; d2 = remainder word count after 32-byte moves
neg.w d2 ; negate to form a backward jump offset
nop ; squoosh pipeline <T8>
jmp @WrLoop(d2.w*4) ; bra. into the loop <T4>
@write32 ;
move.w (a2)+, rDMA(a1) ; do 16 bytes <T7> thru next <T7>
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1) ; do another 16 bytes
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1)
move.w (a2)+, rDMA(a1) ; <T7> from last <T7>
@WrLoop
dbra d4, @write32 ; d4 = # of 32-byte tranfers <T4>
IF PostNOP THEN
nop ; squoosh pipeline <T8>
ENDIF
; INT & TC maybe TRUE at this point
btst.l #31, d2 ; check if we have a residual byte
beq.s @noResidual ;
@residual
move.b (a2)+, rDMA(a3) ; xfer residual byte <T8>
@noResidual
bsr.w WaitForIntNoTime_PSC ; Wait for intrp w/o timeout
; on exit d5 = rFOS|rINT|0|rSTA
bne.s @xferErr ; bra. if xfer err
@2
move.l #$10000, d2 ; init to transfer 64K bytes
dbra d6, @next64KB ;
@goodFWrite ; d1 = # of bytes transferred
moveq.l #noErr, d0 ; successful write op
rts ;
@misAligned ;
subq.l #1, d2 ; adjust for transfer count calc
move.b (a2)+, rFFO(a3) ; ...preload fifo with odd byte <T4> thru next <T4>
bra.w @next64KB ; now we're word aligned
@phaseErr
moveq.l #scPhaseErr, d0 ; return a phase error
bra.s @bytesXferd ; <T4>
@xferErr
moveq.l #scCommErr, d0 ; comm error
@bytesXferd ; <T4>
swap d6 ; calculate bytes left to transfer
move.w d4, d6 ; get low order word
lsl.l #5, d6 ; multiply by 32
ext.l d2 ; make d2 a long
addq.l #1, d2 ; undo adjustment for dbra
add.l d2, d6 ; add to total
moveq.l #iFOFMsk, d2 ; <T8>
and.b rFOS(a3), d2 ; add un-xferred byte in FIFO
add.w d2, d6 ;
sub.l d6, d1 ; result
@badFWrite ; <T4> thru next <T4>
move.l #0, G_FakeStat(a4) ; Return a fake status
move.l #scsiWBlind, d6 ; load proc ID
jsr Error_PSC ; call Error proc - for debug
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T4>
rts ;
;--------------------------------------------------------------------------
; FastRead - implements FastRead
;
; Called by: Transfer
;
; All primitive data transfer routines assume:
;
; Inputs --->
; -> D2.L number of bytes to transfer
; -> D1.L copy of d2
; -> A1 SCSI chip read base address - NON-SERIALIZED
; -> A2 ptr to data buffer - saved
; -> A3 SCSI chip read base address - SERIALIZED
; -> A4 ptr to SCSI Mgr globals
;
; Outputs <---
; <- D0.W error (if any)
; <- D1.L bytes transferred
; <- D5.L xxxx|xxxx|xxxx|rSTA
; <- D3 scratch - saved
; <- D4
; <- D6 scratch - saved
;
; Internal ---
; A0 - scratch - saved
; A1 - SCSI chip read base address - NON-SERIALIZED
; A2 - ptr to data buffer - saved
; A3 - SCSI chip read base address - SERIALIZED
; A4 - ptr to SCSI Mgr globals
; A5 - scratch - saved
;
; Method of Data Transfer: (uses Pseudo-DMA)
; 0) Make sure we got our intrp from the last cmd send
; 1) Parcel transfer into 64KB blocks since TC regr. handles 64KB max
; 2) Read 1st byte if input buffer is NOT word aligned
; 3) Calc. the number of 32-byte block transfers to perform
; 4) Calc. the remaining number of byte transfers to perform
; 5) Read data 32-byte blocks at a time using word MOVEs
; 6) Read remaining data a word at a time
; 7) Transfer residual byte if there is one
FastRead_PSC
bsr HandleSelInProgPSC ; handle unfinished select command
bne.w @phaseErr ; if it is stuck, we are not in data phase
@doRead
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T8>
moveq.l #iPhaseMsk, d0 ; load mask for phase bits <T4> thru next <T4>
and.b rSTA(a3), d0 ; are we in data-in phase?
cmpi.b #iDataIn, d0 ; data-in phase bits = 001
bne.w phaseErr1 ; bra. on phase err
cmpi.l #1, d2 ; special case a 1 byte transfer <T10>
beq.w OneByteRead ;
move.l d2, d6 ; d6 = number 64KB block to perform
swap d6 ; upper word of d6 = lower word of d2
andi.l #$0000FFFF, d2 ; mask out upper word
beq @2 ; if 0 then we have $10000 (64K) bytes to xfer
@next64KB
move.l d2, d4 ; d4 <- d2
move.b d4, rXCL(a3) ; TC regr (least-sig. byte) <- d4.b
lsr.l #8, d4 ; get upper byte of low word
move.b d4, rXCM(a3) ; TC regr (most-sig. byte) <- d4.b <T4>
move.b #cDMAXfer, rCMD(a3) ; load DMA transfer cmd & begin xfers
; DREQ* should be active at this time
; move.l a2, d5 ;
; btst.l #0, d5 ; check if input buffer is on word boundary
; bne.s @misAligned
@aligned
move.w d2, d4 ; d4 = copy of transfer count
lsr.w #5, d4 ; divide xfer count by 32 <T4> thru next <T4>
ror.l #1, d2 ; xfer byte count to word & remember odd byte
and.w #$F, d2 ; d2 = remainder word count after 32-byte moves
neg.w d2 ; negate to form a backward jump offset
nop ; squoosh pipeline <T8>
jmp @RdLoop(d2.w*4) ; bra. into the loop <T4>
@read32 ;
move.w rDMA(a1), (a2)+ ; do 16 bytes <T7> thru next <T7>
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+ ; do another 16 bytes
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+
move.w rDMA(a1), (a2)+ ; <T7> from last <T7>
@RdLoop ; <T4> thru next <T4>
dbra d4, @read32 ; d4 = # of 32-byte transfers
IF PostNOP THEN
nop ; squoosh pipeline <T8>
ENDIF
; INT & TC bits should be TRUE at this point
bsr.w WaitForIntNoTime_PSC ; Wait for intrp w/o timeout
; on exit d5 = rFOS|rINT|0|rSTA
bne.s @xferErr ; bra. if xfer err
btst.l #31, d2 ; check if we have a residual byte
beq.s @2 ; bra. if no residual
@residual
bsr WtForFIFOData ; returns number of bytes in FIFO <T8>
beq.s @timedOut ; <T8>
move.b rFFO(a3), (a2)+ ; xfer residual byte
@2
move.l #$10000, d2 ; init to transfer 64K bytes <T4>
dbra d6, @next64KB ;
@goodFRead ; d1 = # of bytes transferred
moveq.l #noErr, d0 ; successful read op
rts ;
@misAligned
subq.l #1, d2 ; decr. for DBRA <T4> thru next <T4>
move.b rFFO(a3), (a2)+ ; xfer byte from fifo into input buffer
bra.s @aligned ; transfer the rest of data
@timedOut ; <T8>
moveq.l #scBusTOErr, d0 ; if we timed out, return error <T8>
bra.s @bytesXferd ; <T8>
@phaseErr
moveq.l #scPhaseErr, d0 ; return a phase error
bra.s @bytesXferd ; <T4>
@xferErr
moveq.l #scCommErr, d0 ; comm error
@bytesXferd ; <T4>
swap d6 ; calculate bytes left to transfer
move.w d4, d6 ; get low order word
lsl.l #5, d6 ; multiply by 32
ext.l d2 ; make d2 a long
addq.l #1, d2 ; undo adjustment for dbra
add.l d2, d6 ; add to total
sub.l d6, d1 ; d1 = xfer count - bytes remaining to xfer <T4> thru next <T4>
@badFRead
move.l #0, G_FakeStat(a4) ; Return a fake status
move.l #scsiRBlind, d6 ; load proc ID
jsr Error_PSC ; call Error proc - for debug
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T4>
rts ;
;-------------------------------------------------------------------------- <T8> to next <T8>
;
; WtForFIFOData - wait for 256mS for the data to show up in the FIFO
;
; a3 -> SCSI chip read base address - SERIALIZED
; d0 <- number of bytes in FIFO (zero if timed out)
; Z <- .eq.=timed out .ne.=bytes available
;
WtForFIFOData
movem.l d1-d2, -(sp)
move.w TimeSCSIDB, d1 ; get # of DBRAs
lsl.l #8, d1 ; multiply by 256
move.l d1, d2 ; ...a 256mS wait
swap d2
@1
moveq.l #iFOFMsk, d0
and.b rFOS(a3), d0 ; read FIFO flags regr
dbne d1, @1 ; loop until data or timeout
dbne d2, @1 ;
movem.l (sp)+,d1-d2
rts ; <T8> from prev <T8>
;--------------------------------------------------------------------------
;
; ResetBus - Reset the SCSI bus by asserting the SCSI Reset Output signal
; for some number of uS as determined by the clock conv. factor (CCF)
;
; a3 - SCSI chip read base address - SERIALIZED
;
ResetBus_PSC
; disable all intrps
move.b #cRstSBus, rCMD(a3) ; load reset scsi bus cmd <T3>
; re-enable all intrps
rts
;--------------------------------------------------------------------------
;
; WaitForIntNoTime_PSC - infinite loop to wait for a SCSI intrp.
;
; Uses: d0, d5
;
; On exit: d5 = rFOS|rINT|0|rSTA, byte values from the Seq.Step, Status & INT regrs. <T2>
;
; CCR.z = 1, means successful wait
; CCR.z = 0, means failed due to disconnect or lack of bus service req.
WaitForIntNoTime_PSC
@noTimeoutWait
clr.l d5 ;
move.b rSTA(a3), d5 ; read Status regr
btst.l #bINT, d5 ; poll intrp on status regr. for pending intrp
beq.s @noTimeoutWait ; ...loop until intrp req is detected
swap d5 ;
move.b rFOS(a3), d5 ; read FIFO flag/Sequence Step regr
lsl.w #8, d5 ; shift left by 1 byte
move.b rINT(a3), d5 ; read & clear rFOS, rSTA & rINT
move.l d5, d0 ; we got here because of an intrp
swap d5 ; d5 = rFOS|rINT|0|rSTA <T2>
andi.b #iDcBsMsk, d0 ; get Disconnect & Bus Service bits
cmpi.b #iDcBsOK, d0 ; expecting: not disconnected
; & target request info xfer phase
rts ; d5 = rFOS|rINT|0|rSTA <T4> thru next <T4>
;--------------------------------------------------------------------------
;
; HandleSelInProgPSC
;
; 0 if no select in progress or if select is now complete
; 1 if a select is still in progress (i.e. in cmd or msg_out phase)
;
HandleSelInProgPSC
btst.b #SelInProg, G_State96(a4) ; is Select cmd still in progress?
beq.w @skipIt ; no - skip it
btst.b #NeedMsgOut, G_State96(a4) ; are we expecting a Msg_Out phase?
beq.s @chkCmd ; no - see about Command
move.b #iMsgOut, d1 ; yes - wait for this phase or interrupt
bra.s @doWait
@chkCmd
btst.b #NeedCmdSent, G_State96(a4) ; are we expecting a Command phase?
beq.s @wtForFC ; no - wait for an interrupt then
move.b #iCommand, d1 ; yes - wait for this phase or interrupt
@doWait
bsr.s Wt4DREQorIntPSC
bne.s @gotDREQ
@gotInt
bclr.b #FCIntPend, G_State96(a4) ; clear the FC Int pend flag <T8>
bclr.b #SelInProg, G_State96(a4) ; and clear the SelectInProgress flag <T8>
bclr.b #NeedMsgOut, G_State96(a4) ; and Message_Out <T9>
bclr.b #NeedCmdSent, G_State96(a4) ; and Command expected flags <T9>
tst.b d0 ; setup result again
@gotDREQ
@skipIt
rts
@wtForFC
bsr.w WaitForIntNoTime_PSC
moveq.l #0, d0
bra.s @gotInt
;--------------------------------------------------------------------------
;
; Wt4DREQorIntPSC - infinite loop to wait for a DREQ signal or SCSI chip intrp.
;
; Uses: d3, d5
;
; Entry:
; --> d1 = phase to wait for (concurrent with DREQ)
;
; --> G_SCSIDREQ(a4) = addr of DAFB reg (for reading value of
;
; Exit:
; <-- d5 = rFOS|rINT|0|rSTA, byte values from the Seq.Step, Status & INT regrs.
; <-- d0 = 1 if DREQ, 0 if Int
;
;-----------------
HackOutDafb equ 1 ; Moved here because of local labels <SM2> <SM0>
Wt4DREQorIntPSC
jsr SCSIpcTo32Bit_PSC ; clean up PC first
; Check for interrupt first (to avoid unnecessary dog-slow DREQ check)
@noTimeout
clr.l d5 ;
move.b rSTA(a3), d5 ; read Status regr
btst.l #bINT, d5 ; poll intrp on status regr. for pending intrp
bne.s @gotInt ;
IF HackOutDafb THEN
bra.s @noTimeout
ELSE
; If no Interrupt, check for DREQ (go into and out of 32-bit mode to check)
; into 32-bit mode
moveq #true32B, d0 ; switch to 32-bit mode to look at SCSI config regr
jsr SwapMMU ; do it, puts previous mode in D0
move.l G_SCSIDREQ(a4), a0 ; G_SCSIDREQ contains DREQ regr address
move.l (a0), d5 ; read DAFB regr
; out of 32-bit mode (return to previous mode - already in D0)
jsr SwapMMU ; do it, call _SwapMMUMode jump vector
; DREQ?
btst.l #bDREQ, d5 ; do we have an active DREQ from c96
beq.s @noTimeout ; no: try again
ENDIF
@gotDREQ
move.b rSTA(a3), d3 ; get phase value <T9> to next <T9>
and.b #iPhaseMsk, d3 ; load mask bits for phase value
cmp.b d3, d1 ; are we in requested phase?
bne.s @noTimeout ;
moveq.l #1, d3 ; return value = Got DREQ
bra.s @exit
; Get sequence and FIFO status registers into D5 (already got rSTA)
@gotInt
swap d5 ;
move.b rFOS(a3), d5 ; read FIFO flag/Sequence Step regr
lsl.w #8, d5 ; shift left by 1 byte
move.b rINT(a3), d5 ; read & clear rFOS, rSTA & rINT
move.l d5, d0 ; we got here because of an intrp
swap d5 ; d5 = rFOS|rINT|0|rSTA
moveq.l #0, d3 ; return value = Got Interrup
@exit
move.l d3, d0
rts ;
;--------------------------------------------------------------------------
;
; WaitForSCSIIntrp_PSC
;
; Proc to wait for the SCSI interrupt with a 256mS watchdog timer.
;
; Uses: d0, d3, d5
;
; On exit: d5 = rFOS|rINT|0|rSTA, byte values from the Seq.Step,
; Status & INT regrs.
; ccr.z = 1, means timedOut
WaitForSCSIIntrp_PSC
clr.l d5
moveq.l #0, d3 ; clear upper word
move.w TimeSCSIDB, d3 ; get # of DBRAs
lsl.l #8, d3 ; multiply by 256
move.l d3, d0 ; ...a 256mS wait
swap d0
@1
move.b rSTA(a3), d5 ; read Status regr
btst.l #bINT, d5 ; check for c96 INTRP
dbne d3, @1 ; loop until INT is active or timeout
dbne d0, @1 ; loop until INT is active or timeout
beq.s @timedOut ;
swap d5
move.b rFOS(a3), d5 ; read FIFO flag/Sequence Step regr
lsl.w #8, d5 ; shift left by 1 byte
move.b rINT(a3), d5 ; read & clear rFOS, rSTA & rINT
@exit2
swap d5 ;
btst.l #bINT, d5 ; set condition bits
rts ; d5 = rFOS|rINT|0|rSTA
@timedOut
swap d5
move.b rFOS(a3), d5 ; read FIFO flag/Sequence Step regr
lsl.w #8, d5 ; shift left by 1 byte
move.b #0, d5 ; clear rINT value
bra.s @exit2 ;
;--------------------------------------------------------------------------
; FastCompare - implements FastRead
;
; Called by: Transfer
;
; All primitive data transfer routines assume:
;
; d0 - <-- error (if any)
; d1 - --> copy of d2
; d1 - <-- bytes transferred
; d2 - --> number of bytes to transfer
; d3 - scratch - saved
; d4 - --> type of transfer to perform
; d5 - <-- xxxx|xxxx|xxxx|rSTA
; d6 - scratch - saved
;
; a0 - scratch - saved
; a1 - SCSI chip read base address - NON-SERIALIZED
; a2 - ptr to data buffer - saved
; a3 - SCSI chip read base address - SERIALIZED
; a4 - ptr to SCSI Mgr globals
; a5 - scratch - saved
;
; Method of Data Transfer: (uses Pseudo-DMA)
; 0) Make sure we got our intrp from the last cmd send
; 1) Parcel transfer into 64KB blocks since TC regr. handles 64KB max
; 2) Read 1st byte if input buffer is NOT word aligned
; 3) Calc. the number of 32-byte block transfers to perform
; 4) Calc. the remaining number of byte transfers to perform
; 5) Read data 32-byte blocks at a time using word MOVEs
; 6) Read remaining data a word at a time
; 7) Transfer residual byte if there is one
FastComp_PSC
bsr HandleSelInProgPSC ; handle unfinished select command
bne.w @phaseErr ; if it is stuck, we are not in data phase
@doRead
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T8>
moveq.l #iPhaseMsk, d0 ; load mask for phase bits <T4> thru next <T4>
and.b rSTA(a3), d0 ; are we in data-in phase?
cmpi.b #iDataIn, d0 ; data-in phase bits = 001
bne.w phaseErr1 ; bra. on phase err
cmpi.l #1, d2 ; special case a 1 byte compare <T10>
beq.w SlowComp_PSC ; <T5>
clr.l d3 ; init compare status
move.l d2, d6 ; d6 = number 64KB block to perform
swap d6 ; upper word of d6 = lower word of d2
andi.l #$0000FFFF, d2 ; mask out upper word
beq.s @2 ; if 0 then we have $10000 (64K) bytes to xfer
@next64KB
move.l d2, d4 ; d4 <- d2
move.b d4, rXCL(a3) ; TC regr (least-sig. byte) <- d4.b
lsr.l #8, d4 ; get upper byte of low word
move.b d4, rXCM(a3) ; TC regr (most-sig. byte) <- d4.b
move.b #cDMAXfer, rCMD(a3) ; load DMA transfer cmd & begin xfers
; DREQ* should be active at this time
ror.l #1, d2 ; xfer byte count to word & remember odd byte
moveq.l #0, D0 ; clear Z (so dbne doesn't fall thru)
bra.s @RdLpBtm
@RdAndCmp
move.w rDMA(a3), d0 ; <T8>
cmp.w (a2)+, d0 ; compare a word at a time
@RdLpBtm
dbne d2, @RdAndCmp ; loop until done
beq.s @Ok
moveq.l #scCompareErr, d3 ; record a compare error
moveq.l #0, D0 ; clear Z (so dbne doesn't fall thru)
bra.s @RdLpBtm
@Ok
; INT & TC bits should be TRUE at this point
bsr.w WaitForIntNoTime_PSC ; Wait for intrp w/o timeout
; on exit d5 = rFOS|rINT|0|rSTA
bne.s @xferErr ; bra. if xfer err
btst.l #31, d2 ; check if we have a residual byte
beq.s @2 ; bra. if no residual
@residual
bsr WtForFIFOData ; returns number of bytes in FIFO <T8>
beq.s @timedOut ; <T8>
move.b rFFO(a3), D0 ; xfer residual byte
cmp.b (A2)+, D0 ; displace A2 by byte (ignore the result)
@2
move.l #$10000, d2 ; init to transfer 64K bytes
dbra d6, @next64KB ;
@ExitFCmp ; d1 = # of bytes transferred
move.l d3, d0 ; return status
rts ;
@timedOut ; <T8>
moveq.l #scBusTOErr, d0 ; if we timed out, return error <T8>
bra.s @bytesXferd ; <T8>
@phaseErr
moveq.l #scPhaseErr, d0 ; return a phase error
bra.s @bytesXferd
@xferErr
moveq.l #scCommErr, d0 ; comm error
@bytesXferd
swap d6 ; calculate bytes left to transfer
move.w d4, d6 ; get low order word
lsl.l #5, d6 ; multiply by 32
ext.l d2 ; make d2 a long
addq.l #1, d2 ; undo adjustment for dbra
add.l d2, d6 ; add to total
sub.l d6, d1 ; d1 = xfer count - bytes remaining to xfer
@badFRead
move.l #0, G_FakeStat(a4) ; Return a fake status
move.l #scsiRBlind+$F0, d6 ; load proc ID, Fast compare
jsr Error_PSC ; call Error proc - for debug
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO
rts ;
;--------------------------------------------------------------------------
; SlowComp - implements Polled Read
;
; Called by: Transfer
;
; All primitive data transfer routines assume:
;
; d0 - <-- error (if any)
; d1 - --> copy of d2
; d1 - <-- bytes transferred
; d2 - --> number of bytes to transfer
; d3 - scratch - saved
; d4 - --> type of transfer to perform
; d5 - scratch - saved
; d6 - scratch - saved
;
; a0 - scratch - saved
; a1 - SCSI chip read base address - NON-SERIALIZED
; a2 - ptr to data buffer - saved
; a3 - SCSI chip read base address - SERIALIZED
; a4 - ptr to SCSI Mgr globals
; a5 - scratch - saved
;
; Method of Data Transfer: (pDMA and programmed IO) <T5> to next <T5>
; 0) Make sure we got our intrp from the last cmd send
; 1) calculate # of 16-byte block transfers to perform using pDMA & remember the remainder
; 2) Enable c96 DMA and wait till the 16-byte FIFO is full and DREQ is asserted for the 17th byte
; 3) Transfer all data in the FIFO and wait for the intrp
; 4) Repeat until all block have been transferred
; 5) Transfer remaining data using non-DMA transfer command byte then
; Wait and poll for byte-in-fifo interrupt
; 6) Transfer data from fifo to input buffer
; 7) Repeat process until all remaining bytes have been transferred
SlowComp_PSC
bsr HandleSelInProgPSC ; handle unfinished select command
bne.w @phaseErr ; if it is stuck, we are not in data phase
@doRead
moveq.l #iPhaseMsk, d0 ; load mask for phase bits
and.b rSTA(a3), d0 ; are we in data-in phase?
cmpi #iDataIn, d0 ; data-in phase bits = 001
bne.w phaseErr1 ; bra. on phase err
clr.l d3 ; init compare status
move.l d2, d4 ; d4 = copy of transfer count
lsr.l #4, d4 ; divide xfer count by 16
beq.w @16orLess ; bra. if < 16 bytes
subq.l #1, d4 ; adjust for DBRA
move.l d4, d6 ; d4.w has lower 16-byte block count
swap d6 ; d6.w has upper 16-byte word count
@16orMore
; The next few lines are necessary in order to poll DREQ in nuBus
; address space. We don't need to do this if we're xferring <16 bytes.
jsr SCSIpcTo32Bit_PSC ; use pc relative
move.b MMU32Bit, -(sp) ; save current mode on stack
moveq #true32B, d0 ; switch to 32-bit mode to look at SCSI config regr
jsr SwapMMU ; do it, call _SwapMMUMode jump vector
move.l a2, d0 ; get destination addr in d0
_StripAddress ; clear upper byte if necessary
move.l d0, a2 ; a2 = clean buffer ptr
move.l G_SCSIDREQ(a4), a0 ; load SCSI DREQ regr
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO <T8>
move.b #0, rXCM(a3) ; rXCM = 0, clear most-sig. byte count
move.b #$10, rXCL(a3) ; rXCL = 16 bytes, least-sig. byte value
and.l #$F, d2 ; d2 = remainder word count after 16-byte moves
@read16
moveq.l #iPhaseMsk, d5 ; load mask bits for phase value
and.b rSTA(a3), d5 ; are we still in data-in phase?
cmpi.b #iDataIn, d5 ; data-in phase bits = 001
bne.w @premature2 ; no: probably in status phase - split
move.b #cDMAXfer, rCMD(a3) ; load DMA transfer cmd & start loading FIFO
nop ; currently loaded transfer count is used/reused
@1
btst.b #bTRC, rSTA(a3) ; check if we've rcvd all the data <T8> thru next <T8>
bne.s @4 ; if we have, go get the bytes
btst.b #bINT, rSTA(a3) ; poll for unexpected intrp while waiting
bne.w @prematureEnd ; ... maybe disconnected or something catastrophic.
; premature phase change won't generate intrp bit 'cuz of outstanding DREQ...
; ... we have to check this condition explicitly
moveq.l #iPhaseMsk, d5 ; load mask bits for phase value
and.b rSTA(a3), d5 ; are we still in data-in phase?
cmpi.b #iDataIn, d5 ; data-in phase bits = 001
beq.s @1 ; yes, bra. & keep polling
tst.b rXCL(a3) ; not data-in anymore, have we xferred all data (XCL = 0)?
beq.s @1 ; if yes then there MUST be a transfer count zero bit set
bra.w @prematureEnd ; transfer count not 0 so we have a premature end <T8> from prev <T8>
; We need 16 guaranteed DREQs to safely transfer 16 bytes without bus error.
; Ideally, DREQ should be active as long there are threshold number of bytes in the
; FIFO--as the c96 user's guide imply. But the c96 implementation also requires that
; REQ be active in order to get DREQ. This is why we must wait for the 17th REQ from
; the target--and it must remain active--before we proceed with the 16-byte transfer.
@4
move.l (a0), d5 ; read DAFB SCSI DREQ
btst.l #bDREQ, d5 ; poll for DREQ
beq.s @1 ; loop until asserted
btst #4, rFOS(a3) ; see if FIFO is full
beq.s @1 ; loop until asserted
move.w #$7, d5 ; load loop counter, 8 words
@cmpFFO
move.w rDMA(a3), d0 ; <T8>
cmp.w (a2)+, d0 ; compare a word at a time
@cmpLp
dbne d5, @cmpFFO ; continue with compare operation
beq.s @Ok1
moveq.l #scCompareErr, d3 ; record a compare error
moveq.l #0, D0 ; clear Z (so dbne doesn't fall thru)
bra.s @cmpLp
@Ok1
; Note that intrp is asserted only after transfer count is 0, FIFO is empty
; and the target asserts REQ for the next byte.
@2
btst.b #bINT, rSTA(a3) ; check for c96 INTRP
beq.s @2 ; loop until we get the intrp
move.b rINT(a3), d5 ; read Intrp regr & clear rSTA, rSQS & rINT
btst.l #bDSC, d5 ; check for disconnected intrp
bne.s @premature2 ; Branch if transfer error
dbra d4, @read16 ; loop until done, d4 is lower word count
dbra d6, @read16 ; loop until done, d6 is upper word count
move.b (sp)+, d0 ; switch to previous address mode
jsr SwapMMU ; do it, call _SwapMMUMode jump vector
bra.s @16OrLess ; take care of remaining data, if any
@rdSingle ; use non-pDMA for remainder
moveq.l #iPhaseMsk, d5 ; load mask bits for phase value
and.b rSTA(a3), d5 ; are we still in data-in phase?
cmpi.b #iDataIn, d5 ; data-in phase bits = 001
bne.s @phaseErr ; bra. on phase err
move.b #cIOXfer, rCMD(a3) ; load IO transfer cmd & begin xfers
@3
btst.b #bINT, rSTA(a3) ; check for c96 INTRP
beq.s @3 ; loop until we get an intrp
move.b rFFO(a3), d0 ; read byte data from FIFO
cmp.b (a2)+, d0 ; xfer byte from FIFO into input buffer
beq.s @Ok2
moveq.l #scCompareErr, d3 ; record a compare error
@Ok2
move.b rINT(a3), d5 ; read Intrp regr & clear rSTA, rSQS & rINT
btst.l #bDSC, d5 ; check for disconnected intrp
bne.s @xferErr ; Branch if transfer error
@16OrLess
dbra d2, @rdSingle ; read the rest of the remainders
@ExitCmp ; d1 = # of bytes transferred
move.l d3, d0 ; return status
rts ;
; Premature phase change - get leftover bytes out of FIFO, clear DREQ and INTRPT <T8> to next <T8>
@prematureEnd
moveq.l #iFOFMsk, d0 ; use mask to get FIFO flag field
and.b rFOS(a3), d0 ; how many bytes left in FIFO?
bra.s @btmLeftovers
@topLeftovers
move.b rFFO(a3), d5
cmp.w (a2)+, d5 ; compare a word at a time - ignore result
@btmLeftovers
dbra d0,@topLeftovers
@removeDREQ
move.l (a0), d5 ; read DAFB SCSI DREQ
btst.l #bDREQ, d5 ; poll for DREQ - just to be sure
beq.s @5 ; if no DREQ, skip dummy rDMA access
move.w rDMA(a3), d5 ; remove that outstanding DREQ (magic),
bra @removeDREQ ; and see if there's more (more magic)
@5 ; and give us that intrp
bsr.w WaitForIntNoTime_PSC ; Clear pending intrp & get err status
; on exit d5 = rFOS|rINT|0|rSTA
; Premature phase change with no leftover bytes
@premature2
move.b (sp)+, d0 ; switch to previous address mode
jsr SwapMMU ; do it, call _SwapMMUMode jump vector
; calc how many bytes we've xferred...
addq.w #1, d4 ; undo adjustment for dbra
swap d6 ; calculate bytes left to transfer
move.w d4, d6 ; form long word count
lsl.l #4, d6 ; mult by 16
and.b #iPhaseMsk, d5 ; are we still in data-in phase?
cmpi.b #iDataIn, d5 ; data-in phase bits = 001
beq.s @xferErr ; bra. to check for disconnect
@phaseErr
moveq.l #scPhaseErr, d0 ; return a phase error
bra.s @badSCmp ;
@xferErr ; anything else is a comm. err
moveq.l #scCommErr, d0 ; transfer error
@badSCmp
add.l d2, d6 ; add un-xferred remainder
sub.l d6, d1 ; number of bytes transferred
move.l #scsiRead+$F0, d6 ; load proc ID, Slow compare
jsr Error_PSC ; call Error proc - for debug
move.b #cFlshFFO, rCMD(a3) ; Flush FIFO
rts ; <T5>
;___________________________________________________________________________ <T8> to next <T8>
;
; BusErrHandler_PSC
; When the SCSI Mgr is performing a blind data transfer, it patches
; out the bus error vector. The old SCSI Mgr bus error handler
; assumed that if it got called, it must be handling a SCSI bus error.
; Unfortunately, NuBus cards could bus error while the SCSI Mgr is
; installed. To be a better bus error citizen, the SCSI bus error
; handler now checks that the fault address is the SCSI chip, and if
; not, it chains to the bus error handler that it replaced.
;
; This code returns control to Transfer_PSC and not to the routine
; caused the bus error. It does this by popping off the buserr stack
; frame and then doing an RTS, so...
; DON'T PUT ANYTHING ON THE STACK IN TRANSFER ROUTINES (FastRead,
; FastÉ, etc.). At least don't leave it there during periods where a
; buserr may be possible.
;
___________________________________________________________________________;
WITH AEXFrame, XferFrame
savedRegs REG D0-D2/A0-A1 ; save these registers because we need to use them
savedRSize EQU 5*4 ; # bytes on stack for saved registers
BusErrHandler_PSC
; Is it our fault? -----
subq.l #4, sp ; make room for return addr (@notSCSIFault)
movem.l savedRegs, -(sp)
lea savedRSize+4(sp), A0 ; make A0 our AEXFrame pointer (regs+1 LW on stack)
cmp.l SCSIGlobals, A4 ; equal if this is from our transfer routine
bne.s @notSCSIFault
btst.b #HandleBusErrs, G_State96(A4) ; are we supposed to be active?
beq.s @notSCSIFault ; no - not SCSI's fault
move.l SCSIBase, D0 ; check if bus err on SCSI Bus0 address
addi.l #rDMA, D0 ; add pseudo-DMA offset
cmp.l FaultAddr(A0), D0 ; compare with faulted address
beq.s @SCSIFault ; if so, start processing the bus error
addi.l #nonSerlzdDisp, D0 ; add non-serialized offset
cmp.l FaultAddr(A0), D0 ; compare with faulted address
beq.s @SCSIFault ; if so, start processing the bus error
move.l SCSI2Base, D0 ; check if bus err on SCSI Bus1 address
addi.l #rDMA, D0 ; add pseudo-DMA offset
cmp.l FaultAddr(A0), D0 ; compare with faulted address
beq.s @SCSIFault ; if so, start processing the bus error
addi.l #nonSerlzdDisp, D0 ; add non-serialized offset
cmp.l FaultAddr(A0), D0 ; compare with faulted address
beq.s @SCSIFault ; if so, start processing the bus error
; It's not our fault ------
@notSCSIFault
move.l SCSIGlobals, A0 ; put entry point to prev BEH on stack
move.l yeOldeBusErrVct(A0), savedRSize(sp) ; (registers saved beneath return addr)
movem.l (sp)+, savedRegs ; restore regs
rts ; jump to old handler, assuming it'll RTE
; It's all our fault (blame it on us) ------
@SCSIFault
; Clean up the writebacks on the stack frame
move.w WB3S(A0), D0 ; check WB3 for validity
move.l WB3A(A0), A1 ; pass WB Address
move.l WB3D(A0), D1 ; pass WB Data
bsr.w DoWriteBack ; to routine that takes care of it
move.w WB2S(A0), D0 ; check WB2 for validity
move.l WB2A(A0), A1 ; pass WB Address
move.l WB2D(A0), D1 ; pass WB Data
bsr.w DoWriteBack ; to routine that takes care of it
move.w WB1S(A0), D0 ; check WB1 for validity
move.l WB1A(A0), A1 ; pass WB Address
move.l WB1D(A0), D1 ; pass WB Data
bsr.w DoWriteBack ; to routine that takes care of it
; ; old timed routine (using Ticks instead of TimeSCSIDB)
; cmp.l BusErrAddr(A6), A2 ; did we buserr at this point in the xfer b4?
; beq.s @oldBusErr
;@newBusErr
; move.l A2, BusErrAddr(A6) ; remember point in xfer that we got buserr
; move.l blindBusTO(A4), D0 ; init BusErrTO withÉ
; add.l Ticks, D0 ; BlindBusTO+Ticks
; move.l D0, BusErrTO(A6)
;@oldBusErr
; Wait for either DREQ, or INT or a timeout (from blindBusTO value)
jsr SCSIpcTo32Bit_PSC ; use pc relative
moveq #true32B, D0 ; switch to 32-bit mode to look at SCSI config regr
jsr SwapMMU ; (sets up d0 with previous mode)
move.w D0, -(sp) ; save D0 (contains previous MMU mode)
move.l G_SCSIDREQ(A4), A1 ; G_SCSIDREQ contains DREQ regr address
move.l (A1), D0 ; read DAFB regr
btst.l #bDREQ, D0 ; check for active SCSI DREQ
bne.s @retry
move.l blindBusTO(A4), D1
bra.s @outerbtm ; bra to bottom of loop for zero case <2>
@outerTop
move.w TimeSCSIDB, D2
lsr.w #1, D2 ; divide by 2 (because of 5 instr'ns instead of 2) <2>
@1
move.l (A1), D0 ; read DAFB regr
btst.l #bDREQ, D0 ; check for active SCSI DREQ
bne.s @retry
btst #bINT, rSTA(A3) ; see if we have a phase change or something
dbne D2, @1
bne.s @phzChange ;
@outerbtm
dbra D1, @outerTop ; loop dec. on low word of blindBusTO
sub.l #$00010000, D1 ; sub 1 from high word of blindBusTO
bcc.s @outerTop ; loop if result >=0
bra.s @cleanup
; if DREQ, retry the transfer -----
@retry
move.w (sp)+, D0 ; get previous MMU mode into D0
jsr SwapMMU ; return to previous mode
movem.l (sp)+, savedRegs ; restore regs
addq.l #4, sp
rte ; haven't reached max retry count, so restart
; if phase change or timeout, cleanup and abort the transfer -----
@phzChange
@cleanup
; return to previous MMU mode and return SP to the exception stack frame
move.w (sp)+, D0 ; get previous MMU mode into D0
jsr SwapMMU ; return to previous mode
movem.l (sp)+, savedRegs ; restore regs
addq.l #4, sp ; take scratch space off stack
; get any leftover bytes out of the FIFO if we were doing a FastRead
cmp.w #scsiReadFast, transferType(A4)
bne.s @skipLeftovers
move.b rFOS(a3), D0 ; get FIFO status - how many bytes in FIFO
and.w #iFOFMsk, D0 ;
ror.l #1, D0
bra.s @btm0
@top0
move.w rDMA(a3), (A2)+ ; get word from chip and put into user's buffer
@btm0
dbra D0, @top0
tst.l D0
bpl.s @2
move.b rFFO(a3), (A2)+ ; get byte from chip and put into user's buffer
@2
; get rid of excp'n frame and create a throwaway frame for return to Transfer_PSC
@skipLeftovers
move.w xSR(sp), D0 ; save SR for new exception frame
bfextu FrameType(sp){0:4}, D1 ; get format code from stack
cmp.b #AEXFrameType, D1 ; check for 040 Access Error Exception Frame
beq.s @Drop040XFrame ; dispose of 040 AE exception frame
cmp.b #shortBEXFrameType, D1 ; short 020/030 exception frame?
bne.s @Drop46w ; no, so use larger frame
adda.w #shortBEXFrameSize, sp ; dispose of the 16-word frame
bra.s @DummyFrame ; and finish up
@Drop040XFrame ; 040 Bus Error frame-cleaning done here
add.w #aeXFrameSize, sp ; remove 040 Access Error Exception Frame
bra.s @DummyFrame ; and create dummy return frame
@Drop46w
add.w #46*2, sp ; size of exception frame
@DummyFrame
; Fake a format code 0 exception frame (4 words) to finish cleaning up
move.w zeroReg, -(sp) ; format code 0
pea FinishErr ; PC value
move.w d0, -(sp) ; sr value
rte ; 'return' from the fake exception
; If we busErr due to a slow peripheral then the c96 is still expecting to transfer
; data since it has no concept of bus error. Hopefully, the client upon seeing busTOErr
; will do the right thing and call SCSIComplete to clean up the bus.
;-----------------
FinishErr
;-----------------
; What we really need to do here is to first empty the FIFO the call Wt4DREQorIntPSC
; then do the right thing. %%%
moveq.l #scBusTOErr, d0 ; assume bus timeout
btst.b #bINT, rSTA(a3) ; poll for intrp due to premature phase change
beq.s @ErrorDone ; bra. if no SCSI intrp 'cuz we busTO
move.b rINT(a3), d5 ; got intrp so check cause also read & clear rFOS, rSTA & rINT
btst.l #bBSS, d5 ; test for bus service intrp
beq.s @ErrorDone ; bra. if not bus service
moveq.l #scPhaseErr, d0 ; yup it's a premature phase change
@ErrorDone
rts ; return status in d0 to the Transfer routine <T8> from prev <T8>
;-----------------
DoWriteBack
;-----------------
btst #bValid, D0 ; if this writeback valid?
beq.s @wbDone ; no - done
and.w #SIZE_MSK, D0 ; yes, transfer proper size
cmp.w #WB_BYTE, D0
bne.s @1
move.B D1, (A1) ; move Byte
bra.s @wbDone
@1
cmp.w #WB_WORD, D0
bne.s @2
move.W D1, (A1) ; move Word
bra.s @wbDone
@2
cmp.w #WB_LONG, D0
bne.s @wbDone
move.L D1, (A1) ; move LongWord
@wbDone
rts
ENDWITH
;==========================================================================
ENDWITH
END
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