;***********************************************************************
; Synchronous Negotiation (53c700)
;***********************************************************************
; ABSOLUTE declarations

ABSOLUTE SCSI_id = 0

; Messages
ABSOLUTE  CMD_COMPLETE          = 0x00
ABSOLUTE  EXTEND_MSG            = 0x01
ABSOLUTE  SAVE_DATAPTR          = 0x02
ABSOLUTE  DISCONNECT            = 0x04
ABSOLUTE  MSG_REJECT            = 0x07

; Interrupt codes
ABSOLUTE  error_not_cmd_phase         = 0x01
ABSOLUTE  error_not_data_in_phase     = 0x02
ABSOLUTE  error_not_data_out_phase    = 0x03
ABSOLUTE  error_not_msg_in_phase      = 0x04
ABSOLUTE  error_not_msg_out_phase     = 0x05
ABSOLUTE  error_not_status_phase      = 0x06
ABSOLUTE  error_unexpected_phase      = 0x07
ABSOLUTE  error_jump_not_taken        = 0x10
ABSOLUTE  error_not_cmd_complete      = 0x20
ABSOLUTE  error_not_extended_msg      = 0x21
ABSOLUTE  io_complete                 = 0x0A
ABSOLUTE  setup_SXFER                 = 0x888
ABSOLUTE  select_error                = 0xfff
;***********************************************************************
; RELATIVE declarations
RELATIVE  buffers = 0                             ;start of data buffers
RELATIVE  identify_msg_buf=0                      ;identify_msg_buf=1 byte
RELATIVE  ident_and_synch_msg_buf=identify_msg_buf+1;6 bytes
RELATIVE  synch_msgo_buf=ident_and_synch_msg_buf+6;synch_msgo_buf=5 bytes
RELATIVE  synch_msgi_buf=synch_msgo_buf+5         ;synch_msgi_buf=5 bytes
RELATIVE  cmd_buf=synch_msgi_buf+5                ;cmd_buf=12 bytes
RELATIVE  status_buf=cmd_buf+12                   ;stat_buf=1 bytes
RELATIVE  msg_in_buf=status_buf+1                 ;msg_in_buf=10 bytes
RELATIVE  read_data_buf  = msg_in_buf+10               ;longword aligned
RELATIVE write_data_buf = read_data_buf + 512

;***********************************************************************
; ENTRY declarations
ENTRY synch_negot
ENTRY to_decisions
ENTRY id_msg_out
ENTRY msg_in_phase
ENTRY synch_msg_in
ENTRY cmd_phase
ENTRY data_in_phase
ENTRY data_out_phase
ENTRY status_phase
ENTRY alternate_address


;***********************************************************************
; SCRIPT code
synch_negot:
	SELECT ATN SCSI_id, alternate_address
	JUMP to_decisions, WHEN NOT MSG_OUT

	; The extended message (synchronous negotiation) will be sent along 
	; with the identify message.  This will allow synchronous 
	; negotiation before ATN is deasserted.
	;
	; note: ATN is automatically deasserted after a block move for
	;       message out phase
id_msg_out:
	MOVE 6, ident_and_synch_msg_buf, WHEN MSG_OUT
	JUMP to_decisions, WHEN NOT MSG_IN

synch_msg_in_phase:
	MOVE 1, msg_in_buf, WHEN MSG_IN
	CLEAR ACK
	JUMP to_decisions, IF MSG_REJECT      ;compare with message reject
						;and wait for valid phase
	JUMP to_decisions, WHEN NOT MSG_IN
	INT error_not_extended_msg, IF NOT EXTEND_MSG
	MOVE 4, synch_msgi_buf, WHEN MSG_IN
	CLEAR ACK
	INT setup_SXFER                         ;Interrupt to determine                                                              
						;synchronous parameters
cmd_phase:
	clear ATN                               ; For SCSI-1 Compatability
	MOVE 6,cmd_buf, WHEN CMD
	JUMP to_decisions, WHEN NOT DATA_IN
data_in_phase:
	MOVE 512,read_data_buf, WHEN DATA_IN
	JUMP status_phase, WHEN STATUS
	JUMP to_decisions
data_out_phase:
	MOVE 512,write_data_buf, WHEN DATA_OUT
	JUMP to_decisions, WHEN NOT STATUS
status_phase:
	MOVE 1,status_buf, WHEN STATUS
	JUMP to_decisions, WHEN NOT MSG_IN
message_in_phase:
	MOVE 1,msg_buf, WHEN MSG_IN
	INT error_cmd_not_complete, IF NOT 0x00
	CLEAR ACK
	WAIT DISCONNECT
	INT command_complete

to_decisions:
	JUMP msg_in_phase,      WHEN MSG_IN
	JUMP cmd_phase, WHEN CMD
	JUMP data_in_phase, WHEN DATA_IN
	JUMP data_out_phase, WHEN DATA_OUT
	JUMP status_phase, WHEN STATUS
	INT error_unexpected_phase

alternate_address:
	INT select_error