osd-contiki/cpu/6502/net/cs8900a.S
2013-10-03 22:32:12 +02:00

351 lines
7.2 KiB
ArmAsm

;
; Copyright (c) 2007, Adam Dunkels and Oliver Schmidt
; All rights reserved.
;
; Redistribution and use in source and binary forms, with or without
; modification, are permitted provided that the following conditions
; are met:
; 1. Redistributions of source code must retain the above copyright
; notice, this list of conditions and the following disclaimer.
; 2. Redistributions in binary form must reproduce the above copyright
; notice, this list of conditions and the following disclaimer in the
; documentation and/or other materials provided with the distribution.
; 3. Neither the name of the Institute nor the names of its contributors
; may be used to endorse or promote products derived from this software
; without specific prior written permission.
;
; THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
; ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
; IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
; ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
; FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
; OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
; HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
; LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
; OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
; SUCH DAMAGE.
;
; This file is part of the Contiki operating system.
;
; Author: Adam Dunkels <adam@sics.se>, Oliver Schmidt <ol.sc@web.de>
;
;---------------------------------------------------------------------
.segment "JUMPTABLE"
; Driver signature
.byte $65, $74, $68 ; "eth"
.byte $01 ; Ethernet driver API version number
; Ethernet address
mac: .byte $00, $0E, $3A ; OUI of Cirrus Logic
.byte $11, $11, $11
; Buffer attributes
bufaddr:.res 2 ; Address
bufsize:.res 2 ; Size
; Jump table.
.addr init
.addr poll
.addr send
.addr exit
;---------------------------------------------------------------------
.zeropage
sp: .res 2 ; Stack pointer (Do not trash !)
reg: .res 2 ; Address of rxtxreg
ptr: .res 2 ; Indirect addressing pointer
len: .res 2 ; Frame length
cnt: .res 2 ; Frame length counter
;---------------------------------------------------------------------
.rodata
fixup: .byte fixup02-fixup01, fixup03-fixup02, fixup04-fixup03
.byte fixup05-fixup04, fixup06-fixup05, fixup07-fixup06
.byte fixup08-fixup07, fixup09-fixup08, fixup10-fixup09
.byte fixup11-fixup10, fixup12-fixup11, fixup13-fixup12
.byte fixup14-fixup13, fixup15-fixup14, fixup16-fixup15
.byte fixup17-fixup16, fixup18-fixup17, fixup19-fixup18
.byte fixup20-fixup19, fixup21-fixup20, fixup22-fixup21
.byte fixup23-fixup22, fixup24-fixup23, fixup25-fixup24
.byte fixup26-fixup25
fixups = * - fixup
;---------------------------------------------------------------------
rxtxreg := $FF00 ; High byte patched at runtime
txcmd := $FF04 ; High byte patched at runtime
txlen := $FF06 ; High byte patched at runtime
isq := $FF08 ; High byte patched at runtime
packetpp := $FF0A ; High byte patched at runtime
ppdata := $FF0C ; High byte patched at runtime
.data
;---------------------------------------------------------------------
init:
; Save address of rxtxreg
sta reg
stx reg+1
; Start with first fixup location
lda #<(fixup01+1)
ldx #>(fixup01+1)
sta ptr
stx ptr+1
ldx #$FF
ldy #$00
; Fixup address at location
: lda reg
eor (ptr),y ; Use XOR to support C64 RR-Net
sta (ptr),y
iny
lda reg+1
sta (ptr),y
dey
; Advance to next fixup location
inx
cpx #fixups
bcs :+
lda ptr
clc
adc fixup,x
sta ptr
bcc :-
inc ptr+1
bcs :- ; Always
; Activate C64 RR clockport in order to operate RR-Net
; - RR config register overlays CS8900A ISQ register
; - No need to distinguish as ISQ access doesn't hurt
:
fixup01:lda isq+1
ora #$01 ; Set clockport bit
fixup02:sta isq+1
; Accept valid unicast + broadcast frames
; PACKETPP = $0104, PPDATA = $0D05
lda #$04
jsr packetpp_01
lda #$05
ldx #$0D
fixup03:sta ppdata
fixup04:stx ppdata+1
; Set MAC address
; PACKETPP = $0158, PPDATA = MAC[0], MAC[1]
; PACKETPP = $015A, PPDATA = MAC[2], MAC[3]
; PACKETPP = $015C, PPDATA = MAC[4], MAC[5]
ldy #$58
: tya
jsr packetpp_01
lda mac-$58,y
ldx mac-$58+1,y
fixup05:sta ppdata
fixup06:stx ppdata+1
iny
iny
cpy #$58+6
bcc :-
; Turn on transmission and reception of frames
; PACKETPP = $0112, PPDATA = $00D3
lda #$12
jsr packetpp_01
lda #$D3
ldx #$00
fixup07:sta ppdata
fixup08:stx ppdata+1
rts
;---------------------------------------------------------------------
poll:
; Check receiver event register to see if there
; are any valid unicast frames avaliable
; PACKETPP = $0124, PPDATA & $0D00 ?
lda #$24
jsr packetpp_01
fixup09:lda ppdata+1
and #$0D
bne :+
; No frame ready
tax
rts
; Process the incoming frame
; --------------------------
; Read receiver event and discard it
; RXTXREG
:
fixup10:ldx rxtxreg+1
fixup11:lda rxtxreg
; Read frame length
; cnt = len = RXTXREG
fixup12:ldx rxtxreg+1
fixup13:lda rxtxreg
sta len
stx len+1
sta cnt
stx cnt+1
; Adjust odd frame length
jsr adjustcnt
; Is bufsize < cnt ?
lda bufsize
cmp cnt
lda bufsize+1
sbc cnt+1
bcs :+
; Yes, skip frame
jsr skipframe
; No frame ready
lda #$00
tax
rts
; Read bytes into buffer
: jsr adjustptr
:
fixup14:lda rxtxreg
sta (ptr),y
iny
fixup15:lda rxtxreg+1
sta (ptr),y
iny
bne :-
inc ptr+1
dex
bpl :-
; Return frame length
lda len
ldx len+1
rts
;---------------------------------------------------------------------
send:
; Save frame length
sta cnt
stx cnt+1
; Transmit command
lda #$C9
ldx #$00
fixup16:sta txcmd
fixup17:stx txcmd+1
lda cnt
ldx cnt+1
fixup18:sta txlen
fixup19:stx txlen+1
; Adjust odd frame length
jsr adjustcnt
; 8 retries
ldy #$08
; Check for avaliable buffer space
; PACKETPP = $0138, PPDATA & $0100 ?
: lda #$38
jsr packetpp_01
fixup20:lda ppdata+1
and #$01
bne :+
; No space avaliable, skip a received frame
jsr skipframe
; And try again
dey
bne :-
rts
; Send the frame
; --------------
; Write bytes from buffer
: jsr adjustptr
: lda (ptr),y
fixup21:sta rxtxreg
iny
lda (ptr),y
fixup22:sta rxtxreg+1
iny
bne :-
inc ptr+1
dex
bpl :-
rts
;---------------------------------------------------------------------
exit:
rts
;---------------------------------------------------------------------
packetpp_01:
ldx #$01
fixup23:sta packetpp
fixup24:stx packetpp+1
rts
;---------------------------------------------------------------------
skipframe:
; PACKETPP = $0102, PPDATA = PPDATA | $0040
lda #$02
jsr packetpp_01
fixup25:lda ppdata
ora #$40
fixup26:sta ppdata
rts
;---------------------------------------------------------------------
adjustcnt:
lsr
bcc :+
inc cnt
bne :+
inc cnt+1
: rts
;---------------------------------------------------------------------
adjustptr:
lda cnt
ldx cnt+1
eor #$FF ; Two's complement part 1
tay
iny ; Two's complement part 2
sty reg
sec
lda bufaddr
sbc reg
sta ptr
lda bufaddr+1
sbc #$00
sta ptr+1
rts
;---------------------------------------------------------------------