MOVLW   0x05
        CALL    assert_wr
        MOVLW   0xB4
        CALL    assert_wr

        CALL    calc_tcp_sum			;計算TCP的SUM

        MOVLW   0x04
        MOVWF   PORTC
        MOVLW   PAGE_BEGIN
        CALL    assert_wr0

        MOVLW   0x05
        MOVWF   PORTC
        MOVLW   0x3C
        CALL    assert_wr0

        MOVLW   0x06
        MOVWF   PORTC
        CLRW
        CALL    assert_wr0
        CALL    transmit
        CALL    next_seq_no			;seq_no ++
        RETURN

;-----------------------------------------------------------------------------------
;		計算Checksum
calc_tcp_sum:
        CLRF    bytes				;調整2byte對齊

        MOVLW   this_ip				;計算自己的IP地址
        MOVWF   FSR
        MOVF    INDF,W
        CALL    calc_sum
        INCF    FSR,F
        MOVF    INDF,W
        CALL    calc_sum
        INCF    FSR,F
        MOVF    INDF,W
        CALL    calc_sum
        INCF    FSR,F
        MOVF    INDF,W
        CALL    calc_sum

        MOVF    ip_src,W			;計算對方的IP地址
        CALL    calc_sum
        MOVF    ip_src+1,W
        CALL    calc_sum
        MOVF    ip_src+2,W
        CALL    calc_sum
        MOVF    ip_src+3,W
        CALL    calc_sum

        CLRW					;計算協議號
        CALL    calc_sum
        MOVLW   TCP_PROTO
        CALL    calc_sum

        MOVF    remote_len+1,W			;計算byte數量
        CALL    calc_sum
        MOVF    remote_len,W
        CALL    calc_sum

        MOVLW   0x32				;PACKET_SIZE + IP_SIZE + 16
        MOVWF   remote_adr
        MOVLW   PAGE_BEGIN
        MOVWF   remote_adr+1
        CALL    set_checksum			;設置到RTL8019的Buffer
        RETURN

;===================================================================================
;		初始化NIC
;===================================================================================
initialize:
        CALL    init_nic			;Reset NIC
        CALL    getmac				;取得MAC地址
        CALL    setmac				;設置MAC地址
;	初始化RingBuffer
        BSF     STATUS,RP0
        MOVLW   fifo_top
        MOVWF   fifo_buff & 0x7F
        MOVWF   fifo_poi & 0x7F
        MOVWF   fifo_bottom & 0x7F

        CLRF    fifo_cn & 0x7F
        CLRF    fifo_line_cn & 0x7F
        BCF     STATUS,RP0

        RETURN

;-----------------------------------------------------------------------------------
;		RTL8019的Reset
;-----------------------------------------------------------------------------------
reset_nic:
        CLRF    PORTC
        MOVLW   0x21
        CALL    assert_wr0			;STOP OPERATION

        MOVLW   0x1F
        MOVWF   PORTC
        CALL    assert_rd			;讀入1Fh

        MOVLW   0x1F
        MOVWF   PORTC
        MOVF    mdata,W
        CALL    assert_wr0			;回寫1Fh
reset_nic0:
        MOVLW   0x07
        MOVWF   PORTC
        CALL    assert_rd			;讀入Status
        BTFSS   mdata,7
        GOTO    reset_nic0			;檢查Reset是否已經結束
        RETURN

;-----------------------------------------------------------------------------------
;		初始化RTL8019
;-----------------------------------------------------------------------------------
init_nic:
        CALL    reset_nic

        MOVLW   0x0E
        MOVWF   PORTC				;DCR(Data Configuration Register)
        MOVLW   0x68
        CALL    assert_wr0

        MOVLW   0x0A
        MOVWF   PORTC
        CLRW
        CALL    assert_wr0			;for over flow

        MOVLW   0x0B
        MOVWF   PORTC
        CLRW
        CALL    assert_wr0			;for over flow

        MOVLW   0x01
        MOVWF   PORTC
        MOVLW   PAGE_START			;PAGE START
        CALL    assert_wr0

        MOVLW   0x02
        MOVWF   PORTC
        MOVLW   PAGE_STOP			;PAGE STOP
        CALL    assert_wr0

        MOVLW   0x03
        MOVWF   PORTC
        MOVLW   PAGE_START			;BDRY
        CALL    assert_wr0

        MOVLW   0x0C
        MOVWF   PORTC				;RCR
        MOVLW   0x00
        CALL    assert_wr0

        MOVLW   0x0D
        MOVWF   PORTC				;TCR
        MOVLW   0x02				;Loop Back
        CALL    assert_wr0

        MOVLW   0x0F				;IMR
        MOVWF   PORTC
        MOVLW   0x1F
        CALL    assert_wr0

        MOVLW   0x07				;ISR
        MOVWF   PORTC
        MOVLW   0xFF
        CALL    assert_wr0

        CLRF    PORTC				;CR(Command Register)
        MOVLW   0x22				;START OPERATION with L/B
        CALL    assert_wr0
        RETURN

;-----------------------------------------------------------------------------------
;		取得MAC地址
;-----------------------------------------------------------------------------------
getmac:
        CLRF    PORTC
        MOVLW   0x22
        CALL    assert_wr0

        CLRF    remote_adr
        CLRF    remote_adr+1
        MOVLW   .12				;讀12個bytes
        MOVWF   remote_len
        CLRF    remote_len+1
        CALL    remote_read

        MOVLW   0x06
        MOVWF   gcn1				;MAC地址是6 bytes
        MOVLW   mymac				;設置mymac的地址
        MOVWF   FSR
get_mac0:
        MOVLW   0x10
        MOVWF   PORTC
        CALL    assert_rd			;開始讀
        CALL    assert_rd

        MOVF    mdata,W				;將MAC地址讀入PIC
        MOVWF   INDF
        INCF    FSR,F
        DECFSZ  gcn1,F
        GOTO    get_mac0
        RETURN

;-----------------------------------------------------------------------------------
;		設置MAC地址
;-----------------------------------------------------------------------------------
setmac:
; PAGE 1
        CLRF    PORTC
        MOVLW   b'01100010'
        CALL    assert_wr0

        MOVLW   0x01
        MOVWF   PORTC
        MOVLW   mymac
        MOVWF   FSR
        MOVLW   0x06
        MOVWF   gcn1				;MAC地址的長度是6
set_mac0:
        MOVF    INDF,W
        CALL    assert_wr0			;設置MAC地址
        INCF    FSR,F
        INCF    PORTC,F
        DECFSZ  gcn1,F
        GOTO    set_mac0

        MOVLW   0x07
        MOVWF   PORTC
        MOVLW   PAGE_START+1
        CALL    assert_wr0

        MOVLW   0x08
        MOVWF   PORTC
        CLRW
        CALL    assert_wr0
        INCF    PORTC,F
        CLRW
        CALL    assert_wr0
        INCF    PORTC,F
        CLRW
        CALL    assert_wr0
        INCF    PORTC,F
        CLRW
        CALL    assert_wr0
        INCF    PORTC,F
        CLRW
        CALL    assert_wr0
        INCF    PORTC,F
        CLRW
        CALL    assert_wr0
        INCF    PORTC,F
        CLRW
        CALL    assert_wr0
        INCF    PORTC,F
        CLRW
        CALL    assert_wr0

        CLRF    PORTC
        MOVLW   0x22
        CALL    assert_wr0
        RETURN

;-----------------------------------------------------------------------------------
;		準備Remote DMA寫入
;-----------------------------------------------------------------------------------
remote_write:
        MOVLW   0x08
        MOVWF   PORTC
        MOVF    remote_adr,W
        CALL    assert_wr0

        MOVLW   0x09
        MOVWF   PORTC
        MOVF    remote_adr+1,W
        CALL    assert_wr0

        MOVLW   0x0A
        MOVWF   PORTC
        MOVF    remote_len,W
        CALL    assert_wr0

        MOVLW   0x0B
        MOVWF   PORTC
        MOVF    remote_len+1,W
        CALL    assert_wr0

        CLRF    PORTC
        MOVLW   b'00010010'
        CALL    assert_wr0			;可以開始寫入了

        MOVLW   0x10
        MOVWF   PORTC
        RETURN

;-----------------------------------------------------------------------------------
;		準備Remote DMA讀取
;-----------------------------------------------------------------------------------
remote_read:
        MOVLW   0x08
        MOVWF   PORTC
        MOVF    remote_adr,W
        CALL    assert_wr0

        MOVLW   0x09
        MOVWF   PORTC
        MOVF    remote_adr+1,W
        CALL    assert_wr0

        MOVLW   0x0A
        MOVWF   PORTC
        MOVF    remote_len,W
        CALL    assert_wr0

        MOVLW   0x0B
        MOVWF   PORTC
        MOVF    remote_len+1,W
        CALL    assert_wr0

        CLRF    PORTC
        MOVLW   0x0A
        CALL    assert_wr0			;可以開始讀取了

        MOVLW   0x10
        MOVWF   PORTC
        RETURN

;-----------------------------------------------------------------------------------
;		計算Checksum
;-----------------------------------------------------------------------------------
calc_sum:
        BTFSS   bytes,0				;檢查對齊方式
        GOTO    calc_sum_high
; Low Byte
        ADDWF   sum,F
        MOVLW   0x01
        BTFSC   STATUS,C
        ADDWF   sum+1,F
        BTFSC   STATUS,C
        ADDWF   sum,F
        BTFSC   STATUS,C
        ADDWF   sum+1,F
        INCF    bytes,F
        RETURN
; High Byte
calc_sum_high:
        ADDWF   sum+1,F
        MOVLW   0x01
        BTFSC   STATUS,C
        ADDWF   sum,F
        BTFSC   STATUS,C
        ADDWF   sum+1,F
        INCF    bytes,F
        RETURN

assert_wr2times:
        CLRW
        CALL    assert_wr
        CLRW
        GOTO    assert_wr

;-----------------------------------------------------------------------------------
;	送信數據=mdata
assert_wr2x:
        MOVLW   0x01
        ADDWF   remote_len,F
        BTFSC   STATUS,C
        INCF    remote_len+1,F
        MOVF    mdata,W
        GOTO    assert_wr
;	送信數據=W
assert_wr2
        MOVWF   mdata
        MOVLW   0x01
        ADDWF   remote_len,F
        BTFSC   STATUS,C
        INCF    remote_len+1,F
        MOVF    mdata,W

;-----------------------------------------------------------------------------------
;		向RTL8019寫入(考慮Checksum)
;-----------------------------------------------------------------------------------
assert_wr:
        MOVWF   PORTD
assert_wr_2
        BTFSS   bytes,0
        GOTO    assert_wr_high

        ADDWF   sum,F
        MOVLW   0x01
        BTFSC   STATUS,C
        ADDWF   sum+1,F
        BTFSC   STATUS,C
        ADDWF   sum,F
        BTFSC   STATUS,C
        ADDWF   sum+1,F
        INCF    bytes,F
        GOTO    assert_wr0_2
assert_wr_high:
        ADDWF   sum+1,F
        MOVLW   0x01
        BTFSC   STATUS,C
        ADDWF   sum,F
        BTFSC   STATUS,C
        ADDWF   sum+1,F
        INCF    bytes,F
        GOTO    assert_wr0_2

;-----------------------------------------------------------------------------------
;		單純的向RTL8019寫入
;-----------------------------------------------------------------------------------
assert_wr0:
        MOVWF   PORTD
assert_wr0_2:
        BSF     STATUS,RP0
        CLRF    TRISD & 0x7F
        BCF     STATUS,RP0

        BCF     WRITE

        BTFSS   RDY
        GOTO    $-1

        BSF     WRITE

        BSF     STATUS,RP0
        MOVLW   0xFF
        MOVWF   TRISD & 0x7F
        BCF     STATUS,RP0
        RETURN

assert_rd:
        BCF     READ

        BTFSS   RDY				;~Wait
        GOTO    $-1

        MOVF    PORTD,W
        MOVWF   mdata

        BSF     READ
        RETURN

;-----------------------------------------------------------------------------------
;		Packet送信的相關處理
;-----------------------------------------------------------------------------------
transmit_this_ip:
        MOVLW   this_ip
        MOVWF   FSR
        MOVLW   0x04
transmit_nbytes:
        MOVWF   gcn1
        MOVLW   0x10
        MOVWF   PORTC
transmit0:
        MOVF    INDF,W
        CALL    assert_wr
        INCF    FSR,F
        DECFSZ  gcn1,F
        GOTO    transmit0
        RETURN

transmit_nbytes2:
        MOVWF   gcn1
        MOVLW   0x10
        MOVWF   PORTC
transmit2_0
        MOVF    INDF,W
        CALL    assert_wr2
        INCF    FSR,F
        DECFSZ  gcn1,F
        GOTO    transmit2_0
        RETURN

;-----------------------------------------------------------------------------------
;		Packet送信
;-----------------------------------------------------------------------------------
transmit:
retry:
        CLRF    PORTC
        CALL    assert_rd

        BTFSC   mdata,2				;檢查送信bit
        GOTO    transmit			;等待送信

        CLRF    PORTC
        MOVLW   b'00100110'			;設立送信bit
        CALL    assert_wr0			;送信!
trans100:
        MOVLW   0x04
        MOVWF   PORTC
        CALL    assert_rd

        BTFSC   mdata,0
        GOTO    transmit9			;送信完了?
        BTFSC   mdata,3
        GOTO    retry

        GOTO    trans100
transmit9:
        RETURN

;-----------------------------------------------------------------------------------
;		準備Ethernet Header
;-----------------------------------------------------------------------------------
prepare_ether2:
        MOVLW   PACKET_SIZE + ARP_SIZE
        MOVWF   remote_len
        GOTO    prepare_ether1
prepare_ether:
        MOVLW   PACKET_SIZE + IP_SIZE
        MOVWF   remote_len
prepare_ether1:
        CLRF    remote_len+1
        CLRF    remote_adr
        MOVLW   PAGE_BEGIN
        MOVWF   remote_adr+1
        CALL    remote_write

        MOVLW   0x10				;