[fpgaboy.git] / ethernet.asm

	INCLUDE "serial.inc"

ETH_STATUS EQU $FF68
ETH_DATA EQU $FF69
ARP_ENTRIES EQU 6
ARP_ENTRY_SIZE EQU 13

	SECTION "config", HOME[$0]
myMAC:	db $12, $34, $56, $78, $9A, $00
myIP:	db $0A, $00, $00, $02
myMask:	db $FF, $00, $00, $00
myGW:	db $0A, $00, $00, $01

	SECTION "boot", HOME[$100]
	jr start
	nop
	nop
	
	db $CE,$ED,$66,$66,$CC,$0D,$00,$0B,$03,$73,$00,$83       ;<<< no $00,$c3,$50,$01
	db $00,$0C,$00,$0D,$00,$08,$11,$1F,$88,$89,$00,$0E,$DC,$CC,$6E,$E6
	db $DD,$DD,$D9,$99,$BB,$BB,$67,$63,$6E,$0E,$EC,$CC,$DD,$DC,$99,$9F
	db $BB,$B9,$33,$3E     ; Standard Nintendo DO NOT CHANGE...

	db "GB Ethernet     "  ; Cart name   16bytes
	db $00,$00,$00         ; Not used
	db $00                 ; Cart type   ROM Only
	db $00                 ; ROM Size    32k
	db $00                 ; RAM Size     0k
	db $cf,$08             ; Maker ID Matthew Johnson
	db $01                 ; Version     =1
	db $87                 ; Complement check (Important)
	db $ff,$ff             ; Cheksum, fix this if you are going to

start:
	ld sp, $D800
	call zerobss
	PUTSIL "Ethernet test ROM"
.lp:	xor a			; Reset state machines
	ld [ETH_STATUS], a
	ld a, [ETH_STATUS]	; Load current status
	ld [$FF51], a
	and $02		; New packet?
	call nz, getpacket
	jr .lp

zerobss:
	ld hl, bssstart
	ld bc, bssend - bssstart
.lp:	ld a, b
	or c
	ret z
	dec bc
	xor a
	ld [hli], a
	ld a, h
	jr .lp

getpacket:
	ld a, [ETH_DATA]
	ld b, a
	ld a, [ETH_DATA]
	ld c, a
	push bc
	ld hl, packet
.cplp:	ld a, b
	or c
	jr z, .done
	dec bc
	ld a, [ETH_DATA]
	ld [hli], a
	jr .cplp
.done:	pop bc
	PUTSI "getpacket: Got "
	PUTHEX b
	PUTHEX c
	PUTSIL " byte packet from hardware."
	ld hl, packet
	call ether_input
	ret

ether_input:
	push hl
	PUTSI "ether_input: Packet to "
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTSI " from "
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTC $3A
	PUTHEX [hli]
	PUTSI " protocol "
	PUTHEX [hli]
	PUTHEX [hli]
	PUTSIL "."
	pop hl
	
	; Verify the destination MAC.
	push hl
	ld de, myMAC
	ld c, $06
.maclp:	ld a, [de]
	cp [hl]
	jr nz, .notus
	inc de
	inc hl
	dec c
	jr nz, .maclp
	; Done? Then it was to us!
	jr .us
.notus:	; Was it to broadcast?
	pop hl
	push hl
	ld c, $06
.bclp:	ld a, [hli]
	cp $FF
	jr nz, .notbc
	dec c
	jr nz, .bclp

.us:	PUTSIL "ether_input: It's to us!"
	; Which protocol does it belong to?
	pop hl
	ld b, $00
	ld c, 12
	add hl, bc	; Skip source and dest MAC.
	ld a, [hli]
	cp $08
	jr nz, .unknownproto
	ld a, [hli]
	cp $06
	jr z, .arp
	cp $00
	jp z, .ip
	jr .unknownproto

.notbc:	pop hl
	PUTSIL "ether_input: Not addressed to us and not broadcast."
	ret
	
.unknownproto:
	PUTSIL "ether_input: Unknown protocol; dropping"
	ret

.arp:
	PUTSIL "ether_input: ARP packet"
	call arp_input
	ret
.ip:
	PUTSIL "ether_input: IP packet"
	call ip_input
	ret

arp_input:
	; First, verify that this is an ARP packet that we can handle.
	ld c, 7
	ld de, .expectedarp
.cklp:	xor a
	cp c
	jr z, .ckdone
	ld a, [de]
	cp [hl]
	jr nz, .badarp
	inc de
	inc hl
	dec c
	jr .cklp
.ckdone:
	ld a, [hli]
	cp 1
	jr z, .req
	cp 2
	jp z, .resp
.badarp:
	PUTSIL "arp_input: Unknown protocol hardware or request"
	ret
.expectedarp:
	db $00, $01, $08, $00, $06, $04, $00

.req:
	PUTSIL "arp_input.req: Request"
	; Is it asking about us?
	push hl
	ld b, 0
	ld c, $10	; SHA + SPA + THA
	add hl, bc
	ld de, myIP
	ld c, 4
.iplp:	ld a, [de]
	cp [hl]
	jp nz, .notourip
	inc de
	inc hl
	dec c
	jr nz, .iplp
	PUTSIL "arp_input.req: Aimed at us."
	pop hl	; Now synthesize a response packet.
	push hl
	dec hl
	ld a, $02	; Reply!
	ld [hli], a
	ld d, h
	ld e, l
	ld hl, 10	; SHA + SPA
	add hl, de	; Now DE points at SHA, and HL points at THA
	ld c, 10
.dcl:	ld a, [de]
	ld [hli], a
	inc de
	dec c
	jr nz, .dcl
	pop hl		; HL now points at SHA
	ld de, myMAC
	ld c, $06
.mcl:	ld a, [de]
	ld [hli], a
	inc de
	dec c
	jr nz, .mcl
	ld de, myIP	; HL now points at SPA
	ld c, $04
.icl:	ld a, [de]
	ld [hli], a
	inc de
	dec c
	jr nz, .icl
	ld d, h
	ld e, l		; HL now points at THA
	ld hl, -32
	add hl, de	; HL has now been backed up to the start of the ethernet header.
	ld d, h
	ld e, l		; DE now points at the dest
	ld hl, 6
	add hl, de	; HL now points at the source
	ld c, $06
.sdcl:	ld a, [hli]
	ld [de], a
	inc de
	dec c
	jr nz, .sdcl
	ld hl, myMAC	; DE now points at the source
	ld c, $06
.smcl:	ld a, [hli]
	ld [de], a
	inc de
	dec c
	jr nz, .smcl
	ld hl, -12
	add hl, de	; HL now points at the start of the packet -- should be C000!
	ld b, 0
	ld c, 64	; Minimum size packet; avoid transmitting a runt
	call packet_send
	PUTSIL "arp_input.req: sent response!"
	ret
.notourip:
	PUTSIL "arp_input.req: Not aimed at us; ignoring."
	pop hl
	ret
	
.resp:
	PUTSIL "arp_input.resp: Response"
	ret

ip_input:
	; check for ipv4
	ld a, [hl]
	ld c, a
	and $F0
	swap a
	sub $04
	jr z, .ip_isv4
	PUTSIL "ip_input: not ipv4 -- fuck off"
	ret
.ip_isv4
	; get length
	ld a, c
	and $0F
	sla a
	ld c, a
	sla a
	sub $14
	ld b, a
	push bc

	; check checksum
	xor a
	ld d, a
	ld e, a
	push hl
.ip_cksumloop:
	ld a, [hli]
	ld b, a
	ld a, [hli]
	add e
	ld e, a
	ld a, b
	add d
	ld d, a
	jr nc, .ip_noinc
	inc de
.ip_noinc:
	dec c
	jr nz, .ip_cksumloop

	; checksum ok
	pop hl
	ld a, d
	or e
	jr z, .ip_cksumgood
	ld a, d
	and e
	cpl
	or a
	jr z, .ip_cksumgood
	PUTSIL "ip_input: checksum fail -- bailing"
	pop hl
	ret
.ip_cksumgood:
	PUTSIL "ip_input: checksum good"
	ld b, $00
	ld c, $0C
	add hl, bc
	ld c, $04

	; print source IP
	PUTSI "ip_input: this packet is from 0x"
.ip_get_srcip:
	ld a, [hli]
	PUTHEX a
	dec c
	jr nz, .ip_get_srcip
	PUTSIL "."

	; check dest IP
	ld d, myIP >> 8
	ld e, myIP & $FF
	ld c, $04
.ip_chkip:
	ld b, [hl]
	inc hl
	ld a, [de]
	inc de
	cp b
	jr nz, .ip_ipfail
	dec c
	jr nz, .ip_chkip

	PUTSIL "ip_input: wheeeeeeeeeeeeeeee"
	; get protocol in A
	ld d, $FF
	ld e, -$0B
	add hl, de
	ld a, [hl]
	ld d, $00
	ld e, $0B
	add hl, de

	; make hl point at beginning of data
	pop bc
	ld c, b
	ld b, $00
	add hl, bc

	; ok, pass it off to something else
	cp $01
	jr z, .ip_icmp
	cp $11
	jr z, .ip_udp
	ret

.ip_icmp:
	call icmp_input
	ret

.ip_udp:
	call udp_input
	ret

.ip_ipfail:
	PUTSIL "ip_input: this packet is not to our IP address. Bailing."
	pop hl
	ret

icmp_input:
	PUTSIL "icmp_input: too lazy to parse -- fuck off"
	ret

udp_input:
	PUTSIL "udp_input: too lazy to parse -- fuck off"
	ret

packet_send:
	ld a, [ETH_STATUS]	; Wait for the port to become available.
	and $01
	jr nz, packet_send
	ld a, b
	ld [ETH_DATA], a
	ld a, c
	ld [ETH_DATA], a
.pkts:	ld a, b
	or c
	ret z
	dec bc
	ld a, [hli]
	ld [ETH_DATA], a
	jr .pkts

	SECTION "ethdata", BSS
bssstart	DS 0
packet		DS 1552
arptable	DS ARP_ENTRIES * ARP_ENTRY_SIZE
bssend		DS 0
Commit	Line	Data
3a0bde75 JW	1	INCLUDE "serial.inc"
3a0bde75 JW	2
43282fcf JW	3	ETH_STATUS EQU $FF68
43282fcf JW	4	ETH_DATA EQU $FF69
3a0bde75 JW	5	ARP_ENTRIES EQU 6
3a0bde75 JW	6	ARP_ENTRY_SIZE EQU 13
43282fcf	7
43282fcf JW	8	SECTION "config", HOME[$0]
	9	myMAC: db $12, $34, $56, $78, $9A, $00
	10	myIP: db $0A, $00, $00, $02
	11	myMask: db $FF, $00, $00, $00
	12	myGW: db $0A, $00, $00, $01
	13
	14	SECTION "boot", HOME[$100]
	15	jr start
	16	nop
	17	nop
	18
	19	db $CE,$ED,$66,$66,$CC,$0D,$00,$0B,$03,$73,$00,$83 ;<<< no $00,$c3,$50,$01
	20	db $00,$0C,$00,$0D,$00,$08,$11,$1F,$88,$89,$00,$0E,$DC,$CC,$6E,$E6
	21	db $DD,$DD,$D9,$99,$BB,$BB,$67,$63,$6E,$0E,$EC,$CC,$DD,$DC,$99,$9F
	22	db $BB,$B9,$33,$3E ; Standard Nintendo DO NOT CHANGE...
	23
	24	db "GB Ethernet " ; Cart name 16bytes
	25	db $00,$00,$00 ; Not used
	26	db $00 ; Cart type ROM Only
	27	db $00 ; ROM Size 32k
	28	db $00 ; RAM Size 0k
	29	db $cf,$08 ; Maker ID Matthew Johnson
	30	db $01 ; Version =1
	31	db $87 ; Complement check (Important)
	32	db $ff,$ff ; Cheksum, fix this if you are going to
	33
	34	start:
	35	ld sp, $D800
a6035e0c	36	call zerobss
43282fcf	37	PUTSIL "Ethernet test ROM"
a6035e0c	38	.lp: xor a ; Reset state machines
43282fcf	39	ld [ETH_STATUS], a
a6035e0c	40	ld a, [ETH_STATUS] ; Load current status
43282fcf JW	41	ld [$FF51], a
	42	and $02 ; New packet?
	43	call nz, getpacket
	44	jr .lp
	45
a6035e0c JW	46	zerobss:
	47	ld hl, bssstart
	48	ld bc, bssend - bssstart
	49	.lp: ld a, b
	50	or c
	51	ret z
	52	dec bc
	53	xor a
	54	ld [hli], a
	55	ld a, h
	56	jr .lp
	57
43282fcf JW	58	getpacket:
	59	ld a, [ETH_DATA]
	60	ld b, a
	61	ld a, [ETH_DATA]
	62	ld c, a
	63	push bc
a6035e0c	64	ld hl, packet
43282fcf JW	65	.cplp: ld a, b
	66	or c
	67	jr z, .done
	68	dec bc
	69	ld a, [ETH_DATA]
	70	ld [hli], a
	71	jr .cplp
	72	.done: pop bc
	73	PUTSI "getpacket: Got "
	74	PUTHEX b
	75	PUTHEX c
	76	PUTSIL " byte packet from hardware."
3a0bde75	77	ld hl, packet
43282fcf JW	78	call ether_input
	79	ret
	80
	81	ether_input:
	82	push hl
	83	PUTSI "ether_input: Packet to "
	84	PUTHEX [hli]
	85	PUTC $3A
	86	PUTHEX [hli]
	87	PUTC $3A
	88	PUTHEX [hli]
	89	PUTC $3A
	90	PUTHEX [hli]
	91	PUTC $3A
	92	PUTHEX [hli]
	93	PUTC $3A
	94	PUTHEX [hli]
	95	PUTSI " from "
	96	PUTHEX [hli]
	97	PUTC $3A
	98	PUTHEX [hli]
	99	PUTC $3A
	100	PUTHEX [hli]
	101	PUTC $3A
	102	PUTHEX [hli]
	103	PUTC $3A
	104	PUTHEX [hli]
	105	PUTC $3A
	106	PUTHEX [hli]
	107	PUTSI " protocol "
	108	PUTHEX [hli]
	109	PUTHEX [hli]
	110	PUTSIL "."
	111	pop hl
	112
	113	; Verify the destination MAC.
	114	push hl
	115	ld de, myMAC
	116	ld c, $06
	117	.maclp: ld a, [de]
	118	cp [hl]
	119	jr nz, .notus
	120	inc de
	121	inc hl
	122	dec c
	123	jr nz, .maclp
a6035e0c JW	124	; Done? Then it was to us!
	125	jr .us
	126	.notus: ; Was it to broadcast?
43282fcf	127	pop hl
a6035e0c JW	128	push hl
	129	ld c, $06
	130	.bclp: ld a, [hli]
	131	cp $FF
	132	jr nz, .notbc
	133	dec c
	134	jr nz, .bclp
	135
	136	.us: PUTSIL "ether_input: It's to us!"
	137	; Which protocol does it belong to?
	138	pop hl
	139	ld b, $00
	140	ld c, 12
	141	add hl, bc ; Skip source and dest MAC.
	142	ld a, [hli]
	143	cp $08
	144	jr nz, .unknownproto
	145	ld a, [hli]
	146	cp $06
	147	jr z, .arp
	148	cp $00
	149	jp z, .ip
	150	jr .unknownproto
	151
	152	.notbc: pop hl
	153	PUTSIL "ether_input: Not addressed to us and not broadcast."
	154	ret
43282fcf	155
a6035e0c JW	156	.unknownproto:
a6035e0c JW	157	PUTSIL "ether_input: Unknown protocol; dropping"
43282fcf	158	ret
a6035e0c JW	159
	160	.arp:
	161	PUTSIL "ether_input: ARP packet"
	162	call arp_input
	163	ret
	164	.ip:
	165	PUTSIL "ether_input: IP packet"
	166	call ip_input
43282fcf JW	167	ret
43282fcf JW	168
a6035e0c	169	arp_input:
3a0bde75 JW	170	; First, verify that this is an ARP packet that we can handle.
	171	ld c, 7
	172	ld de, .expectedarp
	173	.cklp: xor a
	174	cp c
	175	jr z, .ckdone
	176	ld a, [de]
	177	cp [hl]
	178	jr nz, .badarp
	179	inc de
	180	inc hl
	181	dec c
	182	jr .cklp
	183	.ckdone:
	184	ld a, [hli]
	185	cp 1
	186	jr z, .req
	187	cp 2
	188	jp z, .resp
	189	.badarp:
	190	PUTSIL "arp_input: Unknown protocol hardware or request"
	191	ret
	192	.expectedarp:
	193	db $00, $01, $08, $00, $06, $04, $00
	194
	195	.req:
	196	PUTSIL "arp_input.req: Request"
	197	; Is it asking about us?
	198	push hl
	199	ld b, 0
	200	ld c, $10 ; SHA + SPA + THA
	201	add hl, bc
	202	ld de, myIP
	203	ld c, 4
	204	.iplp: ld a, [de]
	205	cp [hl]
	206	jp nz, .notourip
	207	inc de
	208	inc hl
	209	dec c
	210	jr nz, .iplp
	211	PUTSIL "arp_input.req: Aimed at us."
	212	pop hl ; Now synthesize a response packet.
	213	push hl
	214	dec hl
	215	ld a, $02 ; Reply!
	216	ld [hli], a
	217	ld d, h
	218	ld e, l
	219	ld hl, 10 ; SHA + SPA
	220	add hl, de ; Now DE points at SHA, and HL points at THA
	221	ld c, 10
	222	.dcl: ld a, [de]
	223	ld [hli], a
	224	inc de
	225	dec c
	226	jr nz, .dcl
	227	pop hl ; HL now points at SHA
	228	ld de, myMAC
	229	ld c, $06
	230	.mcl: ld a, [de]
	231	ld [hli], a
	232	inc de
	233	dec c
234	jr nz, .mcl
235	ld de, myIP ; HL now points at SPA
236	ld c, $04
237	.icl: ld a, [de]
238	ld [hli], a
239	inc de
240	dec c
241	jr nz, .icl
242	ld d, h
243	ld e, l ; HL now points at THA
244	ld hl, -32
245	add hl, de ; HL has now been backed up to the start of the ethernet header.
246	ld d, h
247	ld e, l ; DE now points at the dest
248	ld hl, 6
249	add hl, de ; HL now points at the source
250	ld c, $06
251	.sdcl: ld a, [hli]
252	ld [de], a
253	inc de
254	dec c
255	jr nz, .sdcl
256	ld hl, myMAC ; DE now points at the source
257	ld c, $06
258	.smcl: ld a, [hli]
259	ld [de], a
260	inc de
261	dec c
262	jr nz, .smcl
263	ld hl, -12
264	add hl, de ; HL now points at the start of the packet -- should be C000!
265	ld b, 0
266	ld c, 64 ; Minimum size packet; avoid transmitting a runt
267	call packet_send
268	PUTSIL "arp_input.req: sent response!"
269	ret
270	.notourip:
271	PUTSIL "arp_input.req: Not aimed at us; ignoring."
272	pop hl
273	ret
274
275	.resp:
276	PUTSIL "arp_input.resp: Response"
a6035e0c JW	277	ret
	278
	279	ip_input:
f8fc1367 JW	280	; check for ipv4
	281	ld a, [hl]
	282	ld c, a
	283	and $F0
	284	swap a
	285	sub $04
	286	jr z, .ip_isv4
	287	PUTSIL "ip_input: not ipv4 -- fuck off"
	288	ret
	289	.ip_isv4
	290	; get length
	291	ld a, c
	292	and $0F
	293	sla a
	294	ld c, a
	295	sla a
	296	sub $14
	297	ld b, a
	298	push bc
	299
	300	; check checksum
	301	xor a
	302	ld d, a
	303	ld e, a
	304	push hl
	305	.ip_cksumloop:
	306	ld a, [hli]
	307	ld b, a
	308	ld a, [hli]
	309	add e
	310	ld e, a
	311	ld a, b
	312	add d
	313	ld d, a
	314	jr nc, .ip_noinc
	315	inc de
	316	.ip_noinc:
	317	dec c
	318	jr nz, .ip_cksumloop
	319
	320	; checksum ok
	321	pop hl
	322	ld a, d
	323	or e
	324	jr z, .ip_cksumgood
	325	ld a, d
	326	and e
	327	cpl
	328	or a
	329	jr z, .ip_cksumgood
	330	PUTSIL "ip_input: checksum fail -- bailing"
	331	pop hl
	332	ret
	333	.ip_cksumgood:
	334	PUTSIL "ip_input: checksum good"
	335	ld b, $00
	336	ld c, $0C
	337	add hl, bc
	338	ld c, $04
	339
	340	; print source IP
	341	PUTSI "ip_input: this packet is from 0x"
	342	.ip_get_srcip:
	343	ld a, [hli]
344	PUTHEX a
345	dec c
346	jr nz, .ip_get_srcip
347	PUTSIL "."
348
349	; check dest IP
350	ld d, myIP >> 8
351	ld e, myIP & $FF
352	ld c, $04
353	.ip_chkip:
354	ld b, [hl]
355	inc hl
356	ld a, [de]
357	inc de
358	cp b
359	jr nz, .ip_ipfail
360	dec c
361	jr nz, .ip_chkip
362
363	PUTSIL "ip_input: wheeeeeeeeeeeeeeee"
364	; get protocol in A
365	ld d, $FF
366	ld e, -$0B
367	add hl, de
368	ld a, [hl]
369	ld d, $00
370	ld e, $0B
371	add hl, de
372
373	; make hl point at beginning of data
374	pop bc
375	ld c, b
376	ld b, $00
377	add hl, bc
378
379	; ok, pass it off to something else
380	cp $01
381	jr z, .ip_icmp
382	cp $11
383	jr z, .ip_udp
384	ret
385
386	.ip_icmp:
387	call icmp_input
388	ret
389
390	.ip_udp:
391	call udp_input
392	ret
393
394	.ip_ipfail:
395	PUTSIL "ip_input: this packet is not to our IP address. Bailing."
396	pop hl
397	ret
398
399	icmp_input:
400	PUTSIL "icmp_input: too lazy to parse -- fuck off"
401	ret
402
403	udp_input:
404	PUTSIL "udp_input: too lazy to parse -- fuck off"
a6035e0c JW	405	ret
a6035e0c JW	406
3a0bde75 JW	407	packet_send:
	408	ld a, [ETH_STATUS] ; Wait for the port to become available.
	409	and $01
	410	jr nz, packet_send
	411	ld a, b
	412	ld [ETH_DATA], a
	413	ld a, c
	414	ld [ETH_DATA], a
	415	.pkts: ld a, b
	416	or c
	417	ret z
	418	dec bc
	419	ld a, [hli]
	420	ld [ETH_DATA], a
	421	jr .pkts
	422
a6035e0c JW	423	SECTION "ethdata", BSS
	424	bssstart DS 0
	425	packet DS 1552
3a0bde75	426	arptable DS ARP_ENTRIES * ARP_ENTRY_SIZE
a6035e0c	427	bssend DS 0