/// <summary>
/// Replaces all value-flows transferring don't-care values by real values.
/// </summary>
/// <remarks>
/// The semantics of the don't-care symbol admit any such symbol to be replaced with any other symbol, e.g. '0' or '1'
/// without changing the behavior. However, if we blindly replace any don't care symbol with - let's say - logical zeroes,
/// we won't perform optimally, since we might introduce unnecessary multiplexers. Therefore, the method first tries to
/// find existing non-don't-care value-flows as suitable replacement candidates. Only if no such is found, it arbitrarily
/// chooses to replace don't-cares with logical zeroes.
/// </remarks>
public void ReplaceDontCares()
{
var picks = new Dictionary <SignalRef, Flow>();
foreach (var target in FlowTargets)
{
Flow pick = GetFlowsTo(target)
.Where(f => !IsDontCareFlow(f))
.FirstOrDefault();
if (pick == null)
{
ValueFlow vflow = (ValueFlow)GetFlowsTo(target).First();
StdLogicVector data = (StdLogicVector)vflow.Value;
pick = new ValueFlow(StdLogicVector._0s(data.Size), target);
}
picks[target] = pick;
}
var allGraphs = _graphs.Concat(Enumerable.Repeat(_neutral, 1));
foreach (FlowGraph g in allGraphs)
{
var pflow = g.ToFlow();
foreach (Flow flow in pflow.Flows)
{
if (IsDontCareFlow(flow))
{
Flow pick = picks[flow.Target];
g.Add(pick);
}
}
}
}
/// <summary>
/// Replaces the data symbol of a value-flow with the specified symbol.
/// If the old data symbol is a logic vector, the specified symbol is replicated to a vector.
/// </summary>
/// <param name="vflow">a value-flow</param>
/// <param name="symbol">replacement symbol</param>
/// <returns>new value-flow - same target, but different data symbol</returns>
public static ValueFlow AsDontCareFlow(ValueFlow vflow, StdLogic symbol)
{
StdLogicVector?slvdata = vflow.Value as StdLogicVector?;
StdLogic? sldata = vflow.Value as StdLogic?;
if (slvdata.HasValue)
{
return(new ValueFlow(StdLogicVector.AllSame(symbol, slvdata.Value.Size), vflow.Target));
}
if (sldata.HasValue)
{
return(new ValueFlow(symbol, vflow.Target));
}
return(new ValueFlow(StdLogicVector.AllSame(symbol, Marshal.SerializeForHW(vflow.Value).Size), vflow.Target));
}
/// <summary>
/// Replaces any don't-care symbol with the high-impedance symbol.
/// </summary>
public void ReplaceDontCaresByTriStates()
{
var allGraphs = _graphs.Concat(Enumerable.Repeat(_neutral, 1));
foreach (FlowGraph g in allGraphs)
{
var pflow = g.ToFlow();
foreach (Flow flow in pflow.Flows)
{
if (IsDontCareFlow(flow))
{
var oflow = flow as ValueFlow;
var slv = (StdLogicVector)oflow.Value;
var zslv = StdLogicVector.Zs(slv.Size);
var nflow = new ValueFlow(zslv, flow.Target);
g.Add(nflow);
}
}
}
}
/// <summary>
/// Checks whether a given dataflow transfers the don't care literal to its destination.
/// </summary>
/// <param name="flow">a dataflow</param>
public static bool IsDontCareFlow(Flow flow)
{
ValueFlow vflow = flow as ValueFlow;
if (vflow == null)
{
return(false);
}
StdLogicVector?slvdata = vflow.Value as StdLogicVector?;
StdLogic? sldata = vflow.Value as StdLogic?;
if (slvdata.HasValue)
{
return(slvdata.Value.Equals(StdLogicVector.DCs(slvdata.Value.Size)));
}
if (sldata.HasValue)
{
return(sldata.Value.Equals(StdLogic.DC));
}
return(false);
}
public void Transitize()
{
Queue <Flow> q = new Queue <Flow>(_flows.Values);
// DEBUG only
// var copy = new List<KeyValuePair<SignalBase, Flow>>(_flows);
while (q.Any())
{
var flow = q.Dequeue();
SignalFlow sflow = flow as SignalFlow;
if (sflow != null)
{
Flow trflow;
if (_flows.TryGetValue(sflow.Source, out trflow))
{
SignalFlow strflow = trflow as SignalFlow;
if (strflow != null)
{
trflow = new SignalFlow(strflow.Source, sflow.Target);
}
ValueFlow vtrflow = trflow as ValueFlow;
if (vtrflow != null)
{
trflow = new ValueFlow(vtrflow.Value, sflow.Target);
}
_flows[sflow.Target] = trflow;
if (trflow.Equals(sflow))
{
throw new InvalidOperationException("Cyclic dataflow");
}
q.Enqueue(trflow);
}
}
}
}
/// <summary>
/// Replaces the data symbol of a value-flow with the don't care symbol
/// </summary>
/// <param name="vflow">a value-flow</param>
/// <returns>new value-flow - same target, but with don't care symbol</returns>
public static ValueFlow AsDontCareFlow(ValueFlow vflow)
{
return(AsDontCareFlow(vflow, StdLogic.DC));
}
public void Transitize()
{
Queue<Flow> q = new Queue<Flow>(_flows.Values);
// DEBUG only
// var copy = new List<KeyValuePair<SignalBase, Flow>>(_flows);
while (q.Any())
{
var flow = q.Dequeue();
SignalFlow sflow = flow as SignalFlow;
if (sflow != null)
{
Flow trflow;
if (_flows.TryGetValue(sflow.Source, out trflow))
{
SignalFlow strflow = trflow as SignalFlow;
if (strflow != null)
{
trflow = new SignalFlow(strflow.Source, sflow.Target);
}
ValueFlow vtrflow = trflow as ValueFlow;
if (vtrflow != null)
{
trflow = new ValueFlow(vtrflow.Value, sflow.Target);
}
_flows[sflow.Target] = trflow;
if (trflow.Equals(sflow))
throw new InvalidOperationException("Cyclic dataflow");
q.Enqueue(trflow);
}
}
}
}
/// <summary>
/// Replaces any don't-care symbol with the high-impedance symbol.
/// </summary>
public void ReplaceDontCaresByTriStates()
{
var allGraphs = _graphs.Concat(Enumerable.Repeat(_neutral, 1));
foreach (FlowGraph g in allGraphs)
{
var pflow = g.ToFlow();
foreach (Flow flow in pflow.Flows)
{
if (IsDontCareFlow(flow))
{
var oflow = flow as ValueFlow;
var slv = (StdLogicVector)oflow.Value;
var zslv = StdLogicVector.Zs(slv.Size);
var nflow = new ValueFlow(zslv, flow.Target);
g.Add(nflow);
}
}
}
}
/// <summary>
/// Replaces all value-flows transferring don't-care values by real values.
/// </summary>
/// <remarks>
/// The semantics of the don't-care symbol admit any such symbol to be replaced with any other symbol, e.g. '0' or '1'
/// without changing the behavior. However, if we blindly replace any don't care symbol with - let's say - logical zeroes,
/// we won't perform optimally, since we might introduce unnecessary multiplexers. Therefore, the method first tries to
/// find existing non-don't-care value-flows as suitable replacement candidates. Only if no such is found, it arbitrarily
/// chooses to replace don't-cares with logical zeroes.
/// </remarks>
public void ReplaceDontCares()
{
var picks = new Dictionary<SignalRef, Flow>();
foreach (var target in FlowTargets)
{
Flow pick = GetFlowsTo(target)
.Where(f => !IsDontCareFlow(f))
.FirstOrDefault();
if (pick == null)
{
ValueFlow vflow = (ValueFlow)GetFlowsTo(target).First();
StdLogicVector data = (StdLogicVector)vflow.Value;
pick = new ValueFlow(StdLogicVector._0s(data.Size), target);
}
picks[target] = pick;
}
var allGraphs = _graphs.Concat(Enumerable.Repeat(_neutral, 1));
foreach (FlowGraph g in allGraphs)
{
var pflow = g.ToFlow();
foreach (Flow flow in pflow.Flows)
{
if (IsDontCareFlow(flow))
{
Flow pick = picks[flow.Target];
g.Add(pick);
}
}
}
}
/// <summary>
/// Replaces the data symbol of a value-flow with the don't care symbol
/// </summary>
/// <param name="vflow">a value-flow</param>
/// <returns>new value-flow - same target, but with don't care symbol</returns>
public static ValueFlow AsDontCareFlow(ValueFlow vflow)
{
return AsDontCareFlow(vflow, StdLogic.DC);
}
/// <summary>
/// Replaces the data symbol of a value-flow with the specified symbol.
/// If the old data symbol is a logic vector, the specified symbol is replicated to a vector.
/// </summary>
/// <param name="vflow">a value-flow</param>
/// <param name="symbol">replacement symbol</param>
/// <returns>new value-flow - same target, but different data symbol</returns>
public static ValueFlow AsDontCareFlow(ValueFlow vflow, StdLogic symbol)
{
StdLogicVector? slvdata = vflow.Value as StdLogicVector?;
StdLogic? sldata = vflow.Value as StdLogic?;
if (slvdata.HasValue)
return new ValueFlow(StdLogicVector.AllSame(symbol, slvdata.Value.Size), vflow.Target);
if (sldata.HasValue)
return new ValueFlow(symbol, vflow.Target);
return new ValueFlow(StdLogicVector.AllSame(symbol, Marshal.SerializeForHW(vflow.Value).Size), vflow.Target);
}
