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gem5/ext/dsent/model/electrical/Multiplexer.cc
Nilay Vaish c1aecc05e6 ext: dsent: adds a Python interface, drops C++ one 
This patch extensively modifies DSENT so that it can be accessed using Python.
To access the Python interface, DSENT needs to compiled as a shared library.
For this purpose a CMakeLists.txt file has been added.  Some of the code that
is not required is being removed.
2014-10-11 16:16:00 -05:00

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/* Copyright (c) 2012 Massachusetts Institute of Technology
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "model/electrical/Multiplexer.h"
#include <cmath>
#include "model/PortInfo.h"
#include "model/TransitionInfo.h"
#include "model/EventInfo.h"
#include "model/timing_graph/ElectricalDriverMultiplier.h"
#include "model/timing_graph/ElectricalNet.h"
#include "model/std_cells/StdCell.h"
#include "model/std_cells/StdCellLib.h"
namespace DSENT
{
Multiplexer::Multiplexer(const String& instance_name_, const TechModel* tech_model_)
: ElectricalModel(instance_name_, tech_model_)
{
initParameters();
initProperties();
}
Multiplexer::~Multiplexer()
{}
void Multiplexer::initParameters()
{
addParameterName("NumberInputs");
addParameterName("NumberBits");
addParameterName("BitDuplicate", "TRUE");
addParameterName("IsTopLevel", "TRUE");
return;
}
void Multiplexer::initProperties()
{
return;
}
Multiplexer* Multiplexer::clone() const
{
return NULL;
}
void Multiplexer::constructModel()
{
// Get parameters
unsigned int number_bits = (unsigned int) getParameter("NumberBits");
unsigned int number_inputs = (unsigned int) getParameter("NumberInputs");
unsigned int number_selects = (unsigned int) ceil(log2((double) number_inputs));
bool bit_duplicate = (bool) getParameter("BitDuplicate");
bool is_top_level = getParameter("IsTopLevel").toBool();
ASSERT(number_inputs > 0, "[Error] " + getInstanceName() + " -> Number of inputs must be > 0!");
ASSERT(number_bits > 0, "[Error] " + getInstanceName() + " -> Number of bits must be > 0!");
//Construct electrical ports and nets
//Create each input port
for(unsigned int i = 0; i < number_inputs; ++i)
createInputPort( "In" + (String) i, makeNetIndex(0, number_bits-1));
//Create select signals
for(unsigned int i = 0; i < number_selects; ++i)
{
createInputPort( "Sel" + (String)i);
}
//Create output
createOutputPort( "Out", makeNetIndex(0, number_bits-1));
//Create energy, power, and area results
createElectricalResults();
getEventInfo("Idle")->setStaticTransitionInfos();
createElectricalEventResult("Mux");
//Number of inputs on the 0 side
unsigned int inputs_0 = (unsigned int) ceil((double) number_inputs / 2.0);
unsigned int selects_0 = (unsigned int) ceil(log2((double) inputs_0));
//Number of inputs on the 1 side
unsigned int inputs_1 = (unsigned int) floor((double) number_inputs / 2.0);
unsigned int selects_1 = (unsigned int) ceil(log2((double) inputs_1));
//Depending on whether we want to create a 1-bit instance and have it multiplied
//up by number of bits or actually instantiate number_bits of 1-bit instances.
//Recursively instantiates smaller multiplexers
if (bit_duplicate || number_bits == 1)
{
//If it is just a 1-input multiplexer, just connect output to input and be done
if (number_inputs == 1)
{
assign("Out", "In0");
}
else
{
//If it is more than 1 input, instantiate two sub multiplexers (Mux_way0 and Mux_way1)
//and create a final 2:1 mux (muxf) to select between them
String mux0_name = "Mux_way0";
String mux1_name = "Mux_way1";
String muxf_name = "Mux2_i" + (String)number_inputs;
Multiplexer* mux0 = new Multiplexer(mux0_name, getTechModel());
mux0->setParameter("NumberInputs", inputs_0);
mux0->setParameter("NumberBits", 1);
mux0->setParameter("BitDuplicate", "TRUE");
mux0->setParameter("IsTopLevel", "FALSE");
mux0->construct();
Multiplexer* mux1 = new Multiplexer(mux1_name, getTechModel());
mux1->setParameter("NumberInputs", inputs_1);
mux1->setParameter("NumberBits", 1);
mux1->setParameter("BitDuplicate", "TRUE");
mux1->setParameter("IsTopLevel", "FALSE");
mux1->construct();
StdCell* muxf = getTechModel()->getStdCellLib()->createStdCell("MUX2", muxf_name);
muxf->construct();
// TODO hack
// create selector driver at the top level
if(is_top_level)
{
for(unsigned int i = 0; i < number_selects; ++i)
{
StdCell* selinv0 = getTechModel()->getStdCellLib()->createStdCell("INV", String::format("Sel%dInv0", i));
StdCell* selinv1 = getTechModel()->getStdCellLib()->createStdCell("INV", String::format("Sel%dInv1", i));
selinv0->construct();
selinv1->construct();
addSubInstances(selinv0, 1.0);
addElectricalSubResults(selinv0, 1.0);
addSubInstances(selinv1, 1.0);
addElectricalSubResults(selinv1, 1.0);
getEventResult("Mux")->addSubResult(selinv0->getEventResult("INV"), String::format("Sel%dInv0", i), 1.0);
getEventResult("Mux")->addSubResult(selinv1->getEventResult("INV"), String::format("Sel%dInv1", i), 1.0);
}
}
//Create outputs of way0 and way1 multiplexers with final mux
createNet("way0Out");
createNet("way1Out");
portConnect(mux0, "Out", "way0Out");
portConnect(mux1, "Out", "way1Out");
portConnect(muxf, "A", "way0Out");
portConnect(muxf, "B", "way1Out");
// TODO hack
// Connect selector bits
if(is_top_level)
{
for(unsigned int i = 0; i < number_selects; ++i)
{
ElectricalModel* selinv0 = (ElectricalModel*)getSubInstance(String::format("Sel%dInv0", i));
ElectricalModel* selinv1 = (ElectricalModel*)getSubInstance(String::format("Sel%dInv1", i));
createNet("SelInv" + (String)i);
createNet("SelBuf" + (String)i);
portConnect(selinv0, "A", "Sel" + (String)i);
portConnect(selinv0, "Y", "SelInv" + (String)i);
portConnect(selinv1, "A", "SelInv" + (String)i);
portConnect(selinv1, "Y", "SelBuf" + (String)i);
}
}
//Connect inputs to the sub multiplexers.
//Note that multiple inputs are connected to the mux0 and mux1 input and the
//selector signals are connected multiple times. This is just so that everything
//is loaded appropriately since bit duplication is applied
for (unsigned int n = 0; n < number_bits; ++n)
{
//Connect inputs
for (unsigned int i = 0; i < inputs_0; ++i)
portConnect(mux0, "In" + (String) i, "In" + (String) i, makeNetIndex(n));
for (unsigned int i = 0; i < inputs_1; ++i)
portConnect(mux1, "In" + (String) i, "In" + (String) (i + inputs_0), makeNetIndex(n));
// TODO hack
if(is_top_level)
{
//Connect selector bits
for (unsigned int i = 0; i < selects_0; ++i)
portConnect(mux0, "Sel" + (String)i, "SelBuf" + (String)i);
for (unsigned int i = 0; i < selects_1; ++i)
portConnect(mux1, "Sel" + (String)i, "SelBuf" + (String)i);
portConnect(muxf, "S0", "SelBuf" + (String)(number_selects - 1));
}
else
{
//Connect selector bits
for (unsigned int i = 0; i < selects_0; ++i)
portConnect(mux0, "Sel" + (String)i, "Sel" + (String)i);
for (unsigned int i = 0; i < selects_1; ++i)
portConnect(mux1, "Sel" + (String)i, "Sel" + (String)i);
portConnect(muxf, "S0", "Sel" + (String)(number_selects - 1));
}
}
//Connect final mux to outputs
//Because we use bit duplication and so there is only only one multiplexer
//instance, we must use driver multiplier to drive each output appropriately
if (number_bits == 1)
portConnect(muxf, "Y", "Out");
else
{
createNet("OutTemp");
createDriverMultiplier("OutMult");
ElectricalDriverMultiplier* drive_mult = getDriverMultiplier("OutMult");
portConnect(muxf, "Y", "OutTemp");
getNet("OutTemp")->addDownstreamNode(drive_mult);
for (unsigned int n = 0; n < number_bits; ++n)
drive_mult->addDownstreamNode(getNet("Out", makeNetIndex(n)));
}
//Add area, power, and event results for each mux
addSubInstances(mux0, number_bits);
addElectricalSubResults(mux0, number_bits);
addSubInstances(mux1, number_bits);
addElectricalSubResults(mux1, number_bits);
addSubInstances(muxf, number_bits);
addElectricalSubResults(muxf, number_bits);
getEventResult("Mux")->addSubResult(mux0->getEventResult("Mux"), mux0_name, number_bits);
getEventResult("Mux")->addSubResult(mux1->getEventResult("Mux"), mux1_name, number_bits);
getEventResult("Mux")->addSubResult(muxf->getEventResult("MUX2"), muxf_name, number_bits);
}
}
else
{
//Instantiate a bunch of 1-bit multiplexers
for (unsigned int n = 0; n < number_bits; ++n)
{
String mux_name = "Mux_bit" + (String) n;
Multiplexer* mux = new Multiplexer(mux_name, getTechModel());
mux->setParameter("NumberInputs", number_inputs);
mux->setParameter("NumberBits", 1);
mux->setParameter("BitDuplicate", "TRUE");
mux->construct();
// Connect inputs
for (unsigned int i = 0; i < number_inputs; ++i)
portConnect(mux, "In" + (String) i, "In" + (String) i, makeNetIndex(n));
for(unsigned int i = 0; i < number_selects; ++i)
portConnect(mux, "Sel" + (String)i, "Sel" + (String)i);
portConnect(mux, "Out", "Out", makeNetIndex(n));
//Add area, power, and event results for each mux
addSubInstances(mux, 1.0);
addElectricalSubResults(mux, 1.0);
getEventResult("Mux")->addSubResult(mux->getEventResult("Mux"), mux_name, 1.0);
}
}
return;
}
void Multiplexer::propagateTransitionInfo()
{
// The only thing can be updated are the input probabilities...so we will update them
unsigned int number_bits = (unsigned int) getParameter("NumberBits");
unsigned int number_inputs = (unsigned int) getParameter("NumberInputs");
unsigned int number_selects = (unsigned int) ceil(log2((double) number_inputs));
bool bit_duplicate = (bool) getParameter("BitDuplicate");
bool is_top_level = getParameter("IsTopLevel").toBool();
//Number of inputs on the 0 side
unsigned int inputs_0 = (unsigned int) ceil((double) number_inputs / 2.0);
unsigned int selects_0 = (unsigned int) ceil(log2((double) inputs_0));
//Number of inputs on the 1 side
unsigned int inputs_1 = (unsigned int) floor((double) number_inputs / 2.0);
unsigned int selects_1 = (unsigned int) ceil(log2((double) inputs_1));
if (bit_duplicate || number_bits == 1)
{
if (number_inputs == 1)
{
//If theres only 1 input, output transition = input transition
propagatePortTransitionInfo("Out", "In0");
}
else
{
// Update sub muxes with appropriate probabilities
ElectricalModel* mux0 = (ElectricalModel*)getSubInstance("Mux_way0");
for(unsigned int i = 0; i < inputs_0; ++i)
{
propagatePortTransitionInfo(mux0, "In" + (String)i, "In" + (String)i);
}
for(unsigned int i = 0; i < selects_0; ++i)
{
propagatePortTransitionInfo(mux0, "Sel" + (String)i, "Sel" + (String)i);
}
mux0->use();
ElectricalModel* mux1 = (ElectricalModel*)getSubInstance("Mux_way1");
for(unsigned int i = 0; i < inputs_1; ++i)
{
propagatePortTransitionInfo(mux1, "In" + (String)i, "In" + (String)(i + inputs_0));
}
for(unsigned int i = 0; i < selects_1; ++i)
{
propagatePortTransitionInfo(mux1, "Sel" + (String)i, "Sel" + (String)i);
}
mux1->use();
ElectricalModel* muxf = (ElectricalModel*)getSubInstance("Mux2_i" + (String)number_inputs);
propagatePortTransitionInfo(muxf, "A", mux0, "Out");
propagatePortTransitionInfo(muxf, "B", mux1, "Out");
propagatePortTransitionInfo(muxf, "S0", "Sel" + (String)(number_selects-1));
muxf->use();
// TODO hack
if(is_top_level)
{
for(unsigned int i = 0; i < number_selects; ++i)
{
ElectricalModel* selinv0 = (ElectricalModel*)getSubInstance(String::format("Sel%dInv0", i));
ElectricalModel* selinv1 = (ElectricalModel*)getSubInstance(String::format("Sel%dInv1", i));
propagatePortTransitionInfo(selinv0, "A", "Sel" + (String)i);
selinv0->use();
propagatePortTransitionInfo(selinv1, "A", selinv0, "Y");
selinv1->use();
}
}
// Set output transition
propagatePortTransitionInfo("Out", muxf, "Y");
}
}
else
{
// Go through each bit and set the appropriate probability
for (unsigned int n = 0; n < number_bits; ++n)
{
ElectricalModel* mux_bit = (ElectricalModel*)getSubInstance("Mux_bit" + (String) n);
for(unsigned int i = 0; i < number_inputs; ++i)
{
propagatePortTransitionInfo(mux_bit, "In" + (String)i, "In" + (String)i);
}
for(unsigned int i = 0; i < number_selects; ++i)
{
propagatePortTransitionInfo(mux_bit, "Sel" + (String)i, "Sel" + (String)i);
}
mux_bit->use();
}
// Set output probability to be average that of probabilties of each output bit
ElectricalModel* mux_bit = (ElectricalModel*)getSubInstance("Mux_bit0");
propagatePortTransitionInfo("Out", mux_bit, "Out");
}
return;
}
} // namespace DSENT
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