;; #LAYOUT# STD *        #TAKE
;; #LAYOUT# *   *        #IGNORE

;
; The network entries of the Arnitech jump table (mc64 only, arnitech's ADR 0027): whole
; Ethernet frames through the CS8900A at the RR-Net socket, polled, from the Destination
; Address to the end of the data, without the CRC. The chip is found by its Product ID, so
; the routines find an RR-Net on any C64 that has one. Register semantics are the CS8900A
; datasheet's (Cirrus Logic DS271F5) and its 8-bit mode's (AN181).
;
; SAL holds the pointer to the frame or buffer, EAL the bytes left, as LOAD and SAVE use them.
;

!ifdef CONFIG_ARNITECH_CONTROLLER {

	; PacketPage addresses, all but the Product ID's in page $01
	CS_PRODUCT_ID   = $630E           ; at $0000, low byte first
	CS_RX_CFG       = $02             ; bit 6 Skip_1
	CS_RX_CTL       = $04
	CS_LINE_CTL     = $12
	CS_SELF_CTL     = $14             ; bit 6 RESET
	CS_RX_EVENT     = $24             ; bit 8 RxOK
	CS_SELF_ST      = $36             ; bit 7 INITD
	CS_BUS_ST       = $38             ; bit 7 TxBidErr, bit 8 Rdy4TxNOW
	CS_IA           = $58             ; Individual Address, $0158-$015D

	CS_RX_CTL_VALUE = $0D05           ; RxOKA, IndividualA, BroadcastA
	CS_LINE_VALUE   = $00D3           ; SerRxON, SerTxON
	CS_TX_AFTER_ALL = $C0             ; TxCMD: start once the whole frame is in the chip

	NET_NONE_WAITING   = $00
	NET_NO_CARD        = $01
	NET_NO_ROOM        = $02
	NET_LENGTH_REFUSED = $03
	NET_TOO_LONG       = $04

;
; NET_INIT, $FF0C: see ff00.arnitech_jumptable.s
;

arnitech_net_init:

	jsr arnitech_net_probe
	bcs @2

	lda #CS_SELF_CTL
	jsr arnitech_net_point
	lda #$40                           ; RESET, which points the PacketPage pointer at $0000
	sta RRNET_PP_DATA

	lda #CS_SELF_ST
	jsr arnitech_net_point
@1:
	lda RRNET_PP_DATA
	bpl @1                             ; until INITD

	+phy_trash_a
	lda #CS_RX_CTL
	ldx #<CS_RX_CTL_VALUE
	ldy #>CS_RX_CTL_VALUE
	jsr arnitech_net_write
	lda #CS_LINE_CTL
	ldx #<CS_LINE_VALUE
	ldy #>CS_LINE_VALUE
	jsr arnitech_net_write
	+ply_trash_a

	clc
@2:
	rts

;
; NET_MAC, $FF0F: see ff00.arnitech_jumptable.s
;

arnitech_net_mac:

	stx SAL+0
	sty SAL+1
	jsr arnitech_net_probe
	bcs @2

	ldy #$00
@1:
	tya
	ora #CS_IA                         ; $58, $5A, $5C
	jsr arnitech_net_point
	lda RRNET_PP_DATA+0
	sta (SAL), y
	iny
	lda RRNET_PP_DATA+1
	sta (SAL), y
	iny
	cpy #$06
	bne @1

	clc
@2:
	rts

;
; NET_SEND, $FF12: see ff00.arnitech_jumptable.s
;

arnitech_net_send:

	jsr arnitech_net_args
	lda #NET_NO_CARD
	bcs arnitech_net_done

	lda #CS_TX_AFTER_ALL               ; TxCMD, which the high byte's write gives the chip
	sta RRNET_TX_CMD+0
	lda #$00
	sta RRNET_TX_CMD+1
	lda EAL+0                          ; TxLength: the bid, at the high byte's write
	sta RRNET_TX_LENGTH+0
	lda EAL+1
	sta RRNET_TX_LENGTH+1

	lda #CS_BUS_ST
	jsr arnitech_net_point
	lda RRNET_PP_DATA+0
	bmi @1                             ; TxBidErr
	lda RRNET_PP_DATA+1
	lsr                                ; Rdy4TxNOW into carry
	lda #NET_NO_ROOM
	bcc arnitech_net_fail

	clv                                ; memory to chip
	jmp arnitech_net_copy              ; carry clear
@1:
	lda #NET_LENGTH_REFUSED

	; FALLTROUGH

arnitech_net_fail:

	sec

	; FALLTROUGH

arnitech_net_done:

	rts

;
; NET_RECV, $FF15: see ff00.arnitech_jumptable.s
;

arnitech_net_recv:

	jsr arnitech_net_args
	lda #NET_NO_CARD
	bcs arnitech_net_done

	lda #CS_RX_EVENT
	jsr arnitech_net_point
	lda RRNET_PP_DATA+1                ; reading the event clears it
	lsr                                ; RxOK into carry
	lda #NET_NONE_WAITING
	bcc arnitech_net_fail

	lda RRNET_RX_TX_DATA+1             ; RxStatus, high byte first, not needed
	lda RRNET_RX_TX_DATA+0
	ldx RRNET_RX_TX_DATA+1             ; RxLength, high byte first
	lda RRNET_RX_TX_DATA+0

	cpx EAL+1
	bne @1
	cmp EAL+0
	beq @2
@1:
	bcs @3                             ; longer than the buffer
@2:
	sta EAL+0
	stx EAL+1
	pha
	txa
	pha
	bit arnitech_net_copy_end          ; an RTS, $60: sets V, chip to memory
	jsr arnitech_net_copy
	pla
	tay
	pla
	tax
	clc
	rts
@3:
	lda #CS_RX_CFG
	jsr arnitech_net_point
	lda RRNET_PP_DATA+0
	ora #$40                           ; Skip_1: the frame is dropped
	sta RRNET_PP_DATA+0
	lda #NET_TOO_LONG
	bne arnitech_net_fail              ; branch always

;
; The pointer from the zero page address in A into SAL, the length in X/Y into EAL, and the
; chip probed. Out: carry clear if it answers.
;

arnitech_net_args:

	stx EAL+0
	sty EAL+1
	tax
	lda $00, x
	sta SAL+0
	lda $01, x
	sta SAL+1

	; FALLTROUGH

;
; Whether the chip answers: its Product ID at PacketPage $0000. Out: carry clear if it does.
; X and Y are kept.
;

arnitech_net_probe:

	lda #$00
	sta RRNET_PP_POINTER+0
	sta RRNET_PP_POINTER+1
	lda RRNET_PP_DATA+0
	cmp #<CS_PRODUCT_ID
	bne @1
	lda RRNET_PP_DATA+1
	cmp #>CS_PRODUCT_ID
	bne @1
	clc
	rts
@1:
	sec
	rts

;
; PacketPage register $01xx, xx in A, written with X (low byte) and Y (high byte)
;

arnitech_net_write:

	jsr arnitech_net_point
	stx RRNET_PP_DATA+0
	sty RRNET_PP_DATA+1
	rts

;
; The PacketPage pointer at $01xx, xx in A. X and Y are kept.
;

arnitech_net_point:

	sta RRNET_PP_POINTER+0
	lda #$01
	sta RRNET_PP_POINTER+1
	rts

;
; EAL bytes between the chip's receive and transmit data port and SAL: from the chip with V
; set, to it with V clear. Even bytes go through the port's low byte, odd ones through its
; high byte. Out: carry clear.
;

arnitech_net_copy:

	ldy #$00
@1:
	lda EAL+0
	ora EAL+1
	beq @4
	tya
	and #$01
	tax
	bvs @2
	lda (SAL), y
	cpx #$01                           ; plain stores: an indexed one reads the port
	beq @7                             ; first, which takes a byte of a received frame
	sta RRNET_RX_TX_DATA+0
	bvc @3                             ; branch always
@7:
	sta RRNET_RX_TX_DATA+1
	bvc @3                             ; branch always
@2:
	lda RRNET_RX_TX_DATA, x
	sta (SAL), y
@3:
	iny
	bne @5
	inc SAL+1
@5:
	lda EAL+0
	bne @6
	dec EAL+1
@6:
	dec EAL+0
	jmp @1
@4:
	clc

arnitech_net_copy_end:

	rts
}