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nes-proj/platform/c64/net/cs8900a.c

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/*
* Copyright (c) 2001, Adam Dunkels.
* 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. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 C64 RealAudio server demo project.
*
* $Id: cs8900a.c,v 1.1 2006/06/17 22:41:26 adamdunkels Exp $
*
*/
/* cs8900a.c: device driver for the CS8900a chip in 8-bit mode. Mostly
written in 6502 assembler for speed. */
#include "cs8900a.h"
#include "contiki-net.h"
extern u8_t *cs8900a_rxtxreg,
*cs8900a_txcmd,
*cs8900a_txlen,
*cs8900a_packetpp,
*cs8900a_ppdata;
static u16_t len;
static u16_t cnt;
/*-----------------------------------------------------------------------------------*/
#pragma optimize(push, off)
void
cs8900a_init(void)
{
/* Turn on transmission and reception of frames. */
/* PACKETPP = 0x0112;
PPDATA = 0x00c0; */
asm("lda #$12");
asm("sta %v", cs8900a_packetpp);
asm("lda #$01");
asm("sta %v+1", cs8900a_packetpp);
asm("lda #$c0");
asm("sta %v", cs8900a_ppdata);
asm("lda #$00");
asm("sta %v+1", cs8900a_ppdata);
/* Accept valid unicast+broadcast frames. */
/* PACKETPP = 0x0104;
PPDATA = 0x0d05; */
asm("lda #$04");
asm("sta %v", cs8900a_packetpp);
asm("lda #$01");
asm("sta %v+1", cs8900a_packetpp);
asm("lda #$05");
asm("sta %v", cs8900a_ppdata);
asm("lda #$0d");
asm("sta %v+1", cs8900a_ppdata);
/* Set MAC address. */
/* PACKETPP = 0x0158;
PPDATA = (ETHADDR1 << 8) | (ETHADDR0); */
asm("lda #$58");
asm("sta %v", cs8900a_packetpp);
asm("lda #$01");
asm("sta %v+1", cs8900a_packetpp);
asm("lda %v", uip_ethaddr);
asm("sta %v", cs8900a_ppdata);
asm("lda %v+1", uip_ethaddr);
asm("sta %v+1", cs8900a_ppdata);
/* PACKETPP = 0x015a;
PPDATA = (ETHADDR3 << 8) | (ETHADDR2); */
asm("lda #$5a");
asm("sta %v", cs8900a_packetpp);
asm("lda #$01");
asm("sta %v+1", cs8900a_packetpp);
asm("lda %v+2", uip_ethaddr);
asm("sta %v", cs8900a_ppdata);
asm("lda %v+3", uip_ethaddr);
asm("sta %v+1", cs8900a_ppdata);
/* PACKETPP = 0x015c;
PPDATA = (ETHADDR5 << 8) | (ETHADDR4); */
asm("lda #$5c");
asm("sta %v", cs8900a_packetpp);
asm("lda #$01");
asm("sta %v+1", cs8900a_packetpp);
asm("lda %v+4", uip_ethaddr);
asm("sta %v", cs8900a_ppdata);
asm("lda %v+5", uip_ethaddr);
asm("sta %v+1", cs8900a_ppdata);
}
#pragma optimize(pop)
/*-----------------------------------------------------------------------------------*/
#pragma optimize(push, off)
void
cs8900a_send(void)
{
/* Transmit command. */
asm("lda #$c0");
asm("sta %v", cs8900a_txcmd);
asm("lda #$00");
asm("sta %v+1", cs8900a_txcmd);
asm("lda %v", uip_len);
asm("sta %v", cs8900a_txlen);
asm("lda %v+1", uip_len);
asm("sta %v+1", cs8900a_txlen);
asm("ldy #8");
tryagain:
/* Check for avaliable buffer space. */
asm("lda #$38");
asm("sta %v", cs8900a_packetpp);
asm("lda #$01");
asm("sta %v+1", cs8900a_packetpp);
asm("lda %v+1", cs8900a_ppdata);
asm("and #1");
asm("bne %g", send);
/* No space avaliable, skip a received frame and try again. */
asm("lda #$02");
asm("sta %v", cs8900a_packetpp);
asm("lda #$01");
asm("sta %v+1", cs8900a_packetpp);
asm("lda %v", cs8900a_ppdata);
asm("ora #$40");
asm("sta %v", cs8900a_ppdata);
asm("dey");
asm("bne %g", tryagain);
return;
/* Send the frame. */
send:
/* First, send 14+40=54 bytes of header. */
asm("ldy #0");
sendloop1:
asm("lda %v,y", uip_buf);
asm("sta %v", cs8900a_rxtxreg);
asm("iny");
asm("lda %v,y", uip_buf);
asm("sta %v+1", cs8900a_rxtxreg);
asm("iny");
asm("cpy #%b", UIP_LLH_LEN + UIP_TCPIP_HLEN);
asm("bne %g", sendloop1);
if(uip_len <= UIP_LLH_LEN + UIP_TCPIP_HLEN) {
return;
}
/* Next, send rest of the packet. */
cnt = uip_len - (UIP_LLH_LEN + UIP_TCPIP_HLEN);
asm("lda %v", cnt);
asm("lsr");
asm("bcc %g", noinc);
asm("inc %v", cnt);
asm("bne %g", noinc);
asm("inc %v+1", cnt);
noinc:
asm("lda %v", uip_appdata);
asm("sta ptr1");
asm("lda %v+1", uip_appdata);
asm("sta ptr1+1");
asm("ldy #0");
sendloop2:
asm("lda (ptr1),y");
asm("sta %v", cs8900a_rxtxreg);
asm("iny");
asm("lda (ptr1),y");
asm("sta %v+1", cs8900a_rxtxreg);
asm("iny");
asm("bne %g", check);
asm("inc ptr1+1");
check:
asm("cpy %v", cnt);
asm("bne %g", sendloop2);
asm("dec %v+1", cnt);
asm("bpl %g", sendloop2);
}
#pragma optimize(pop)
/*-----------------------------------------------------------------------------------*/
#pragma optimize(push, off)
static void
skip_frame(void)
{
/* PACKETPP = 0x0102;
PPDATA = PPDATA | 0x0040; */
asm("lda #$02");
asm("sta %v", cs8900a_packetpp);
asm("lda #$01");
asm("sta %v+1", cs8900a_packetpp);
asm("lda %v", cs8900a_ppdata);
asm("ora #$40");
asm("sta %v", cs8900a_ppdata);
}
#pragma optimize(pop)
/*-----------------------------------------------------------------------------------*/
#pragma optimize(push, off)
u16_t
cs8900a_poll(void)
{
/* Check receiver event register to see if there are any valid
unicast frames avaliable. */
/* PACKETPP = 0x0124;
if(PPDATA & 0x000d == 0x0000) {
return 0;
}
*/
asm("lda #$24");
asm("sta %v", cs8900a_packetpp);
asm("lda #$01");
asm("sta %v+1", cs8900a_packetpp);
asm("lda %v+1", cs8900a_ppdata);
asm("and #$0d");
asm("cmp #$00");
asm("bne %g", noreturn);
/* No frame ready. */
return 0;
noreturn:
/* Process the incoming frame. */
/* Read receiver event and discard it. */
/* RXTXREG; */
asm("lda %v+1", cs8900a_rxtxreg);
asm("lda %v", cs8900a_rxtxreg);
/* Read frame length. */
/* cnt = len = RXTXREG; */
asm("lda %v+1", cs8900a_rxtxreg);
asm("sta %v+1", len);
asm("sta %v+1", cnt);
asm("lda %v", cs8900a_rxtxreg);
asm("sta %v", len);
asm("sta %v", cnt);
asm("lsr");
asm("bcc %g", noinc);
asm("inc %v", cnt);
asm("bne %g", noinc);
asm("inc %v+1", cnt);
noinc:
if(cnt > UIP_BUFSIZE) {
skip_frame();
return 0;
}
/* Read bytes into uip_buf. */
asm("lda #<%v", uip_buf);
asm("sta ptr1");
asm("lda #>%v", uip_buf);
asm("sta ptr1+1");
asm("ldy #0");
readloop:
asm("lda %v", cs8900a_rxtxreg);
asm("sta (ptr1),y");
asm("iny");
asm("lda %v+1", cs8900a_rxtxreg);
asm("sta (ptr1),y");
asm("iny");
asm("bne %g", check);
asm("inc ptr1+1");
check:
asm("cpy %v", cnt);
asm("bne %g", readloop);
asm("dec %v+1", cnt);
asm("bpl %g", readloop);
return len;
}
#pragma optimize(pop)
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