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SSwitch.cpp
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SSwitch.cpp
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// Copyright (c) 2011, Richard Osborne, All rights reserved
// This software is freely distributable under a derivative of the
// University of Illinois/NCSA Open Source License posted in
// LICENSE.txt and at <http://github.xcore.com/>
#include "SSwitch.h"
#include "Resource.h"
#include "Node.h"
#include "SystemState.h"
#include "Trace.h"
#include <cassert>
SSwitch::SSwitch(Node *p) :
parent(p),
regs(p),
recievedTokens(0),
junkIncomingTokens(0),
sendingResponse(false),
sentTokens(0),
responseLength(0)
{
setJunkIncoming(false);
}
static uint16_t read16_be(const Token *p)
{
return (p[0].getValue() << 8) | p[1].getValue();
}
static uint32_t read32_be(const Token *p)
{
return (p[0].getValue() << 24) | (p[1].getValue() << 16) |
(p[2].getValue() << 8) | p[3].getValue();
}
static void write32_be(Token *p, uint32_t value)
{
p[0] = Token(value >> 24);
p[1] = Token((value >> 16) & 0xff);
p[2] = Token((value >> 8) & 0xff);
p[3] = Token(value & 0xff);
}
static bool containsControlToken(const Token *p, unsigned size)
{
for (unsigned i = 0; i < size; ++i) {
if (p[i].isControl())
return true;
}
return false;
}
bool SSwitch::parseRequest(ticks_t time, Request &request) const
{
if (recievedTokens == 0)
return false;
if (!buf[0].isControl())
return false;
unsigned expectedLength;
switch (buf[0].getValue()) {
default:
return false;
case CT_READC:
expectedLength = readRequestLength;
request.write = false;
break;
case CT_WRITEC:
expectedLength = writeRequestLength;
request.write = true;
break;
}
if (recievedTokens != expectedLength)
return false;
if (containsControlToken(&buf[1], expectedLength - 1))
return false;
request.returnNode = read16_be(&buf[1]);
request.returnNum = buf[3].getValue();
request.regNum = read16_be(&buf[4]);
if (request.write) {
request.data = read32_be(&buf[6]);
} else {
request.data = 0;
}
return true;
}
void SSwitch::handleRequest(ticks_t time, const Request &request)
{
bool ack;
uint32_t value = 0;
ResourceID destID = ResourceID::chanendID(request.returnNum,
request.returnNode);
if (request.write) {
ack = regs.write(request.regNum, request.data);
if (Tracer::get().getTracingEnabled()) {
Tracer::get().SSwitchWrite(*parent, destID, request.regNum, request.data);
if (ack)
Tracer::get().SSwitchAck(*parent, destID);
else
Tracer::get().SSwitchNack(*parent, destID);
}
} else {
ack = regs.read(request.regNum, value);
if (Tracer::get().getTracingEnabled()) {
Tracer::get().SSwitchRead(*parent, destID, request.regNum);
if (ack)
Tracer::get().SSwitchAck(*parent, value, destID);
else
Tracer::get().SSwitchNack(*parent, destID);
}
}
ChanEndpoint *dest = parent->getChanendDest(destID);
if (!dest)
return;
bool junkPacket = false;
if (!dest->claim(this, junkPacket)) {
assert(0 && "TODO");
}
if (junkPacket)
return;
sendingResponse = true;
sentTokens = 0;
responseLength = 0;
if (ack) {
buf[responseLength++] = Token(CT_ACK, true);
if (!request.write) {
write32_be(&buf[responseLength], value);
responseLength += 4;
}
} else {
buf[responseLength++] = Token(CT_NACK, true);
}
buf[responseLength++] = Token(CT_END, true);
if (!dest->canAcceptTokens(responseLength)) {
assert(0 && "TODO");
}
for (unsigned i = 0; i < responseLength; i++) {
if (buf[i].isControl()) {
dest->receiveCtrlToken(time, buf[i].getValue());
} else {
dest->receiveDataToken(time, buf[i].getValue());
}
}
sendingResponse = false;
}
void SSwitch::notifyDestClaimed(ticks_t time)
{
// TODO
assert(0);
}
void SSwitch::notifyDestCanAcceptTokens(ticks_t time, unsigned tokens)
{
// TODO
assert(0);
}
bool SSwitch::canAcceptToken()
{
return !sendingResponse;
}
bool SSwitch::canAcceptTokens(unsigned tokens)
{
return !sendingResponse;
}
void SSwitch::receiveDataToken(ticks_t time, uint8_t value)
{
if (junkIncomingTokens) {
return;
}
if (recievedTokens == writeRequestLength) {
junkIncomingTokens = true;
return;
}
buf[recievedTokens++] = Token(value);
}
void SSwitch::receiveDataTokens(ticks_t time, uint8_t *values, unsigned num)
{
if (junkIncomingTokens) {
return;
}
if (recievedTokens + num > writeRequestLength) {
junkIncomingTokens = true;
return;
}
for (unsigned i = 0; i < num; i++) {
buf[recievedTokens++] = Token(values[i]);
}
}
void SSwitch::receiveCtrlToken(ticks_t time, uint8_t value)
{
switch (value) {
case CT_END:
Request request;
if (!junkIncomingTokens && parseRequest(time, request)) {
handleRequest(time, request);
}
recievedTokens = 0;
junkIncomingTokens = false;
release(time);
return;
case CT_PAUSE:
release(time);
return;
}
if (junkIncomingTokens) {
return;
}
if (recievedTokens == writeRequestLength) {
junkIncomingTokens = true;
return;
}
buf[recievedTokens++] = Token(value, true);
}