PR#3
PREFIX /A2OSX.SRC
LOMEM $A00
INC 1
AUTO 6
				.LIST OFF	
*--------------------------------------
ARP.CLEAR		ldx #K.ARPCACHE.SIZE*S.ARPCACHE
.1				stz ARP.CACHE-1,x
				dex
				bne .1
				clc
				rts
*--------------------------------------
* ARP.QUERY
*  In:
*   PULLW PTR to IP
*   PULLW PTR to MAC (to fill)
*  Out:
*   CC: hit: MAC filled
*   CS: missed 
*--------------------------------------
ARP.QUERY		>PULLW ZPPtrIP			IP
				>PULLW ZPPtrMAC			MAC
				
				ldy #3
.1				lda (ZPPtrIP),y
				sta ARP.TmpCache+S.ARPCACHE.IP,y
				dey
				bpl .1
				jsr ARP.QUERY.I
				bcs .9
				
				ldy #5
.2				lda ARP.TmpCache+S.ARPCACHE.MAC,y
				sta (ZPPtrMAC),y
				dey
				bpl .2
				clc
.9				rts				
*--------------------------------------
* ARP.ADD
*  In:
*   PULLW PTR to IP
*   PULLW PTR to MAC
*--------------------------------------
ARP.ADD			>PULLW ZPPtrIP			IP
				>PULLW ZPPtrMAC			MAC
				
				stz ARP.TmpCache+S.ARPCACHE.TTL
				stz ARP.TmpCache+S.ARPCACHE.TTL+1

				ldy #3
.1				lda (ZPPtrIP),y
				sta ARP.TmpCache+S.ARPCACHE.IP,y
				dey
				bpl .1
				
				ldy #5
.2				lda (ZPPtrMAC),y
				sta ARP.TmpCache+S.ARPCACHE.MAC,y
				dey
				bpl .2

				lda #S.ARPCACHE.STATUS.RESOLVED+S.ARPCACHE.STATUS.STATIC
				
ARP.ADD.I		sta ARP.TmpCache

				jsr ARP.FIND.BY.IP
				bcc .1
				jsr ARP.FIND.FREE
				
.1				ldy #S.ARPCACHE-1
.2				lda ARP.TmpCache,y
				sta (ZPCachePtr),y
				dey
				bpl .2
				
				clc
				rts
*--------------------------------------
* ARP.GETCACHE
*  Out:
*   Y,A = PTR to ARP.CACHE
*--------------------------------------
ARP.GETCACHE	>LDYA L.ARP.CACHE
				clc
				rts
*--------------------------------------
*				PRIVATE
*--------------------------------------
ARP.IN			ldy #S.ARP.TPA+3
				ldx #3
				
.1				lda (ZPFrameInPtr),y
				cmp IPCFG+S.IPCFG.IP,x
				bne ARP.IN.EXIT
				dey
				dex
				bpl .1
				
				ldy #S.ARP.OPERATION+1	HI byte
				lda (ZPFrameInPtr),y
				cmp #S.ARP.OPERATION.REQ
				beq ARP.IN.REQ
				
				cmp #S.ARP.OPERATION.REP
				beq ARP.IN.REP
				
ARP.IN.EXIT		lda hFrameIn
				>SYSCALL FreeMemA
				clc
				rts
				
ARP.IN.REQ		ldy #S.ARP.SPA+3
				ldx #3
				
.1				lda (ZPFrameInPtr),y
				sta ARP.REP.TPA,x
				dey
				dex
				bpl .1
				
				ldy #S.ARP.SHA+5
				ldx #5
				
.2				lda (ZPFrameInPtr),y
				sta ARP.REP.DSTMAC,x
				sta ARP.REP.THA,x
				dey
				dex
				bpl .2
				
				>LDYA L.ARP.REP
				ldx #DEVMGR.WRITEBLOCK
				jsr NetDevJmp
				bra ARP.IN.EXIT

ARP.IN.REP		lda #K.ARP.TTL
				sta ARP.TmpCache+S.ARPCACHE.TTL
				lda /K.ARP.TTL
				sta ARP.TmpCache+S.ARPCACHE.TTL+1
				
				ldy #S.ARP.SPA+3
				ldx #3
				
.1				lda (ZPFrameInPtr),y
				sta ARP.TmpCache+S.ARPCACHE.IP,x
				dey
				dex
				bpl .1

				ldy #S.ARP.SHA+5
				ldx #5
				
.2				lda (ZPFrameInPtr),y
				sta ARP.TmpCache+S.ARPCACHE.MAC,x
				dey
				dex
				bpl .2
				
				lda #S.ARPCACHE.STATUS.RESOLVED
				
				jsr ARP.ADD.I
				jmp ARP.IN.EXIT
*--------------------------------------
ARP.QUERY.I		jsr ARP.FIND.BY.IP
				bcs .3					send an ARP request

				lda (ZPCachePtr)		get status...
				bpl .9					Pending...
				
				ldy #S.ARPCACHE.MAC
				
.2				lda (ZPCachePtr),y
				sta ARP.TmpCache,y
				iny
				cpy #S.ARPCACHE.MAC+6
				bne .2
				clc
				rts

.3				ldx #3

.4				lda ARP.TmpCache+S.ARPCACHE.IP,x
				sta ARP.REQ.TPA,x
				dex
				bpl .4
				
				>LDYA L.ARP.REQ
				ldx #DEVMGR.WRITEBLOCK
				jsr NetDevJmp

				bcs .99
				
				lda #K.ARP.PENDING.TTL
				sta ARP.TmpCache+S.ARPCACHE.TTL
				stz ARP.TmpCache+S.ARPCACHE.TTL+1
				
				lda #S.ARPCACHE.STATUS.PENDING
				jsr ARP.ADD.I
				
.9				lda #ERR.ARP.PENDING
				sec		
.99				rts		
*--------------------------------------
ARP.FIND.BY.IP	>LDYA L.ARP.CACHE
				>STYA ZPCachePtr

				lda #K.ARPCACHE.SIZE
				sta TmpOffset
				
.1				lda (ZPCachePtr)
				beq .3

				ldx #3
				ldy #S.ARPCACHE.IP+3
				
.2				lda ARP.TmpCache+S.ARPCACHE.IP,x
				cmp (ZPCachePtr),y
				bne .3
				dey
				dex
				bpl .2
				clc
				rts
				
.3				lda ZPCachePtr
				clc
				adc #S.ARPCACHE
				sta ZPCachePtr
				bcc .8
				inc ZPCachePtr+1
				
.8				dec TmpOffset
				bne .1
				sec
				rts
*--------------------------------------
ARP.FIND.FREE	>LDYA L.ARP.CACHE
				>STYA ZPCachePtr

				lda #$ff
				sta TmpDWord
				sta TmpDWord+1

				ldx #K.ARPCACHE.SIZE
				
.1				lda (ZPCachePtr)
				beq .8
				bpl .6
				
				ldy #S.ARPCACHE.TTL
				lda (ZPCachePtr),y
				sec
				sbc TmpDWord
				iny
				lda (ZPCachePtr),y
				sbc TmpDWord+1
				bcc .6
				
				lda (ZPCachePtr),y
				sta TmpDWord+1
				dey
				lda (ZPCachePtr),y
				sta TmpDWord
				
				>LDYA ZPCachePtr
				>STYA ZPTmpPtr1			save lowest TTL slot ...

.6				lda ZPCachePtr
				clc
				adc #S.ARPCACHE
				sta ZPCachePtr
				bcc .7
				inc ZPCachePtr+1
				
.7				dex
				bne .1
				
				>LDYA ZPTmpPtr1
				>STYA ZPCachePtr
				lda #0
				sta (ZPCachePtr)
				
.8				clc
				rts
*--------------------------------------
ARP.EXPIRE		>LDYA L.ARP.CACHE
				>STYA ZPCachePtr
				
				ldx #K.ARPCACHE.SIZE
				
.1				lda (ZPCachePtr)
				beq .2
				
				ldy #S.ARPCACHE.TTL
				sec
				lda (ZPCachePtr),y
				sbc #1
				sta (ZPCachePtr),y
				iny
				lda (ZPCachePtr),y
				sbc #0
				sta (ZPCachePtr),y
				bcs .2
				
				lda #0
				sta (ZPCachePtr)
				
.2				lda ZPCachePtr
				clc
				adc #S.ARPCACHE
				sta ZPCachePtr
				bcc .3
				inc ZPCachePtr+1
				
.3				dex
				bne .1
				rts
*--------------------------------------
MAN
SAVE LIB/LIBTCPIP.S.ARP
LOAD LIB/LIBTCPIP.S
ASM