sym895scr.n

IXP425的BSP代码

;*/

doDataOut:

move    PHASE_DATA_OUT to SCRATCHA3

; scattered data transfers are implemented here.

; first check if its scattered data transfer or not 

move   SCRATCHC0 to SFBR

jump   REL(doScatDataOut) if not 0

; its not scattered data transfer.

move    from OFFSET_DATA_OUT, when DATA_OUT

jump    REL(nextPhase)

doScatDataOut:

; save the initial DSA register for restoring afterwards.

move DSA0 + 0 to SFBR

move SFBR to SCRATCHD0

move DSA1 + 0 to SFBR

move SFBR to SCRATCHD1

move DSA2 + 0 to SFBR

move SFBR to SCRATCHD2

move DSA3 + 0 to SFBR

move SFBR to SCRATCHD3


; we have to do a scatered data transfer. 
; scratchc1 contains the total number of scattered elements
; scratchc2 contains how many are remaining elements to be transferred.

move   SCRATCHC1 to SFBR

scatDataStart:

; now see if any more scattered data  is to be transferred.

move   SFBR to SCRATCHC2

jump   REL(scatDataEnd) if 0

move   from OFFSET_SCAT_DATA, when DATA_OUT      ; transfer data 

move   DSA0 + 8 to DSA0            ; point to next data location.

jump   REL(scatNoCarry), if not carry

move   DSA1 + 0 to SFBR with carry

move   SFBR to DSA1

move   DSA2 + 0 to SFBR with carry

move   SFBR to DSA2

move   DSA3 + 0 to SFBR with carry

move   SFBR to DSA3

scatNoCarry:

; by now address is successfully incremented.

move   SCRATCHC2 - 1 to SFBR

jump   REL(scatDataStart)

;Target changed the phase

int    SYM895_ILLEGAL_PHASE

scatDataEnd:

move SCRATCHD0 to SFBR

move SFBR to DSA0

move SCRATCHD1 to SFBR

move SFBR to DSA1

move SCRATCHD2 to SFBR

move SFBR to DSA2

move SCRATCHD3 to SFBR

move SFBR to DSA3

jump   REL(nextPhase)

;/************************************************************************
; *
; * doDataIn  - handle Data In phase
; */

doDataIn:

move    PHASE_DATA_IN to SCRATCHA3             

move    from OFFSET_DATA_IN, when DATA_IN

jump    REL(nextPhase)


;/************************************************************************
; *
; * doCommand  - handle Command phase
; */

doCommand:

move    PHASE_COMMAND to SCRATCHA3           

move    from OFFSET_CMD, when CMD

jump    REL(nextPhase)


;/************************************************************************
; *
; * doStatus  - handle STATUS phase
; */

doStatus:

move    PHASE_STATUS to SCRATCHA3            

move    from OFFSET_STATUS, when STATUS

jump    REL(nextPhase)


;/************************************************************************
; *
; * doMsgOut  - handle MSG OUT phase
; */

doMsgOut:

move    PHASE_MSG_OUT to SCRATCHA3              

move    SCRATCHA1 to SFBR

int     SYM895_NO_MSG_OUT if M_OUT_NONE         ; if msg out state is none
                                                ; Inform Host.
call    REL(assertAtn) if M_OUT_SENT            ; assert ATN for retries.

move    from OFFSET_MSG_OUT, when MSG_OUT        ; transfer data

move    M_OUT_SENT to SFBR

move    SFBR to SCRATCHA1                       ; set msg out state to SENT

jump    REL(nextPhase)



;/************************************************************************
; *
; * doMsgIn  - handle MSG IN phase
; */

doMsgIn:

; Now we have a message to be recieved. This could be a simple or a multibyte
; message. We can check the message type and do a little processing here.
; But unless we can take a decision here, we will defer the processing to
; the host. Multi Byte messages are handled separately.


move    PHASE_MSG_IN to SCRATCHA3             

move    SCRATCHA2 to SFBR

jump    REL(contExtMsg) if M_IN_EXT_MSG_DATA    

move    from OFFSET_MSG_IN, when MSG_IN          ; get the data in

jump    REL(twobyte) if 0x20 and mask 0x0f      ; a two byte message.

; now check the message type

jump    REL(disconn) if M_DISCONNECT            ; Disconnect message

jump    REL(complete) if M_CMD_COMPLETE         ; command complete message

jump    REL(extended) if M_EXT_MSG              ; extended message

int     SYM895_MESSAGE_IN_RECVD                 ; host handles the rest of them.

;
; received the Disconnect message
;

disconn:

move    0x00 to SCNTL2

clear   ack

call    REL(timeoutEnable)

wait    disconnect

int     SYM895_DISCONNECTED


;
; received a Command Complete message
;
 
complete:

move    0x00 to SCNTL2

clear   ack

call    REL(timeoutEnable)

wait    disconnect

int     SYM895_CMD_COMPLETE


;
; Received the first byte of a Two Byte message.
; read the second byte and interrupt the host.
;

twobyte:

clear   ack

move    from OFFSET_MSG_IN_SECOND, when MSG_IN

int     SYM895_MESSAGE_IN_RECVD


;
; Received the first byte of a Multi Byte message.
; Read the message size and interrupt host.
;
extended:

clear	ack

move	from OFFSET_MSG_IN_SECOND, when MSG_IN

move	M_IN_EXT_MSG_DATA to sfbr

move	sfbr to SCRATCHA2

int	SYM895_EXT_MESSAGE_SIZE

contExtMsg:

clear	ack

move	from OFFSET_MSG_IN_REST, when MSG_IN

move	M_IN_NONE to sfbr

move	sfbr to SCRATCHA2

int	SYM895_MESSAGE_IN_RECVD			; at last !

;/******************************************************************************
; *
; * sym895TgtDisconnect - disconnect from SCSI bus
; *
; */

PROC sym895TgtDisconnect:

call	REL(mismatchATNIntrDisable)

set	target

disconnect

clear	target

int	SYM895_DISCONNECTED

;/******************************************************************************
; * sym895Diag - Diagnotic instructions used in Loopback mode testing.
; */

PROC sym895Diag:

select  ATN from LOOPBACK_DEVICE_OFFS, REL(checkNewCmd)

move    from LOOPBACK_IDENT_OUT_OFFS, when MSG_OUT

move    from LOOPBACK_DATA_OUT_OFFS, when DATA_OUT

;/******************************************************************************
;*
;* miscellaneous useful subroutines - mainly to improve readability of the
;* main script.
;*/

;
; assertAtn - assert the SCSI ATN signal
;
assertAtn:

set	atn

return

;
; timeoutEnable - enable the SCSI {inter-byte, select, disconnect} timeout
;
timeoutEnable:

move	(STIME0_HTH_TIMEOUT | STIME0_SEL_TIMEOUT) to stime0

return

;
; timeoutDisable - disable the SCSI {inter-byte, select, disconnect} timeout
;

timeoutDisable:

;move	(~STIME0_HTH_MASK & stime0) to stime0 ; Disable HTH timeout
;move	(~STIME0_SEL_MASK & stime0) to stime0 ; Disable SEL timeout

move  	0x0 to sfbr

move 	sfbr to stime0

return

;
; mismatchATNIntrEnable - enable the phase mismatch / ATN interrupt
;
mismatchATNIntrEnable:

move	sien0 | SIEN0_MISMATCH_ATN to sfbr

move	sfbr to sien0

return

;
; mismatchATNIntrDisable - disable the phase mismatch / ATN interrupt
;
mismatchATNIntrDisable:

;move	sien0 & ~SIEN0_MISMATCH_ATN to sfbr

move	sien0 & 0x7f to sfbr

move	sfbr to sien0

return

; End of Script