X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/43282fcf13e571f4a57dd8df10ea9b4f7f8d1bca..f8fc136727e9a5259529a58e2a2ada1c93d0dd17:/ethernet.asm

diff --git a/ethernet.asm b/ethernet.asm
index 4bcee82..8fb4fed 100644
--- a/ethernet.asm
+++ b/ethernet.asm
@@ -1,35 +1,10 @@
+	INCLUDE "serial.inc"
+
 ETH_STATUS EQU $FF68
 ETH_DATA EQU $FF69
+ARP_ENTRIES EQU 6
+ARP_ENTRY_SIZE EQU 13
 
-PUTC: MACRO
-	ld a, \1
-	call putc
-	ENDM
-
-PUTS: MACRO
-	ld hl, \1
-	call puts
-	ENDM
-
-PUTSI: MACRO
-	push hl
-	call putsi
-	db \1, 0
-	pop hl
-	ENDM
-
-PUTSIL: MACRO
-	push hl
-	call putsi
-	db \1, 13, 10, 0
-	pop hl
-	ENDM
-
-PUTHEX: MACRO
-	ld a, \1
-	call puthex
-	ENDM
-	
 	SECTION "config", HOME[$0]
 myMAC:	db $12, $34, $56, $78, $9A, $00
 myIP:	db $0A, $00, $00, $02
@@ -58,22 +33,35 @@ myGW:	db $0A, $00, $00, $01
 
 start:
 	ld sp, $D800
+	call zerobss
 	PUTSIL "Ethernet test ROM"
-.lp:	xor a			; Rest state machines
+.lp:	xor a			; Reset state machines
 	ld [ETH_STATUS], a
-	ld a, [ETH_STATUS]	; New shit?
+	ld a, [ETH_STATUS]	; Load current status
 	ld [$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, $D000
+	ld hl, packet
 .cplp:	ld a, b
 	or c
 	jr z, .done
@@ -86,7 +74,7 @@ getpacket:
 	PUTHEX b
 	PUTHEX c
 	PUTSIL " byte packet from hardware."
-	ld hl, $D000
+	ld hl, packet
 	call ether_input
 	ret
 
@@ -133,82 +121,307 @@ ether_input:
 	inc hl
 	dec c
 	jr nz, .maclp
-	PUTSIL "ether_input: It's to us!"
+	; Done? Then it was to us!
+	jr .us
+.notus:	; Was it to broadcast?
 	pop hl
-	
-	ret
-.notus:	PUTSIL "ether_input: Not to us..."
+	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
-	ret
+	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
 
-; SERIAL ROUTINES ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+.notbc:	pop hl
+	PUTSIL "ether_input: Not addressed to us and not broadcast."
+	ret
+	
+.unknownproto:
+	PUTSIL "ether_input: Unknown protocol; dropping"
+	ret
 
-putc:
-	push af
-.waitport:
-	ld a,[$FF53]
-	and $01
-	jr nz,.waitport
-	pop af
-	ld [$FF52],a
+.arp:
+	PUTSIL "ether_input: ARP packet"
+	call arp_input
+	ret
+.ip:
+	PUTSIL "ether_input: IP packet"
+	call ip_input
 	ret
 
-puts:
+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 $00
-	ret z
-	call putc
-	jr puts
-
-EX_SP_HL: MACRO
-	push de
-	di
-	add sp, 2
-	pop de
+	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 l, e
-	ld h, d
-	add sp, -2
-	ei
-	pop de
-	ENDM
-
-putsi:
-	pop hl
-	push af
-	push bc
-	push de
-.lp:	ld a, [hli]
-	or a
-	jr z, .done
-	call putc
-	jr .lp
-.done:	pop de
-	pop bc
-	pop af
+	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
 
-puthex:				; Put two hex nibbles to the serial console.
-	push bc
-	push hl
-	push af
-	swap a
-	and $0F
-	ld hl,hex
-	ld b,0
-	ld c,a
-	add hl,bc
+ip_input:
+	; check for ipv4
 	ld a, [hl]
-	call putc
-	pop af
+	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
-	ld hl,hex
-	ld c,a
-	add hl,bc
-	ld a, [hl]
-	call putc
+	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
-hex:	db "0123456789ABCDEF"
+
+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