Merge branch 'devel' of gitlab.lip6.fr:vlsi-eda/coriolis into devel

More generic H-Tree support to accomodate the LS180 PLL internal clock.
The H-Tree support is now allowed for any net, not only the clocks and not only top-level nets. This allow to better management of the LS180 internal clock signal. * New: In Cell::flattenNets(Instance*,set<string>,uint64_t) new overload of the function to allow the user to select nets that will *not* be flattened. This makes the NoClockFlatten flag effectively obsolete, we keep it for backward compatibility. The net names can be of non top level ones. In that case, they must use the name an HyperNet will get (the Occurrence name). For example: "instance1.instance2.deep_net_name". * New: In PyCell, update the wrapper for the new parameter of flattenNets(), new utility function pyListToStringSet() to translate a Python list into a C++ set of names. * New: In EtesianEngine, add support for a list of nets to be excluded from the flattening procedure. Those excluded nets will also be excludeds from the Coloquinte nets *and* HFNS synthesis, as they are likely to be manageds by a H-Tree. * Change: In AnabaticEngine::_loadGrByNet(), now also skip nets that are flagged as manually detailed route. * New: In AnabaticEngine::antennaProtect(), do not try to insert diodes on nets that are already fixed or detaled route. This replace the clock exclusion. * New: In cumulus/plugins.{block,htree,chip}, replace the concept of clock-tree by the more generic H-Tree. That is, we can ask the P&R to create H-Tree on any net of the design, not only the ones matcheds as clock. The net does not even need to be top-level. This is to manage the PLL internal clock generated by the PLL in the LS180 chip. Start to change all reference to "clock" into "H-Tree". * Bug: In cumulus/plugins.chip.powerplanes.Builder._connectHTree(), there was an inversion of the H & V routing gauges to compute the track into which put the H-Tree center to corona edge wiring. This was causing tracks to be used twice, seen in the ao68000 test bench.
2021-05-31 00:07:15 +02:00 · 2021-05-31 00:02:23 +02:00
17 changed files with 299 additions and 170 deletions
--- a/anabatic/src/AnabaticEngine.cpp
+++ b/anabatic/src/AnabaticEngine.cpp
@ -1241,6 +1241,8 @@ namespace Anabatic {
        //AutoSegment::setShortNetMode( true );
          ++shortNets;
        }
+        if (NetRoutingExtension::isManualDetailRoute(net))
+          continue;
        if (  NetRoutingExtension::isManualGlobalRoute(net)
           or NetRoutingExtension::isAutomaticGlobalRoute(net)) {
          DebugSession::open( net, 145, 150 );
--- a/anabatic/src/AntennaProtect.cpp
+++ b/anabatic/src/AntennaProtect.cpp
@ -1057,7 +1057,9 @@ namespace Anabatic {
    uint32_t total  = 0;
    for ( Net* net : getCell()->getNets() ) {
      if (net->isSupply()) continue;
-      if (net->isClock ()) continue;
+      if (  NetRoutingExtension::isManualDetailRoute(net)
+         or NetRoutingExtension::isFixed(net))
+        continue;
      antennaProtect( net, failed, total );
    }
    cmess2 << Dots::asString    ( "     - Antenna gate maximum WL"   , DbU::getValueString(etesian->getAntennaGateMaxWL()) ) << endl;
--- a/anabatic/src/AutoHorizontal.cpp
+++ b/anabatic/src/AutoHorizontal.cpp
@ -94,13 +94,13 @@ namespace Anabatic {
      }
    }

-    if (getId() == 1518590) {
-      cerr << "AutoHorizontal::_postCreate(): " << this << endl;
-      cerr << "| Source contact:" << source     << endl; 
-      cerr << "| Source GCell:  " << getGCell() << endl; 
-      cerr << "| Target contact:" << target     << endl; 
-      cerr << "| Target GCell:  " << target->getGCell() << endl; 
-    }
+    // if (getId() == 1518590) {
+    //   cerr << "AutoHorizontal::_postCreate(): " << this << endl;
+    //   cerr << "| Source contact:" << source     << endl; 
+    //   cerr << "| Source GCell:  " << getGCell() << endl; 
+    //   cerr << "| Target contact:" << target     << endl; 
+    //   cerr << "| Target GCell:  " << target->getGCell() << endl; 
+    // }
  }


--- a/cumulus/src/CMakeLists.txt
+++ b/cumulus/src/CMakeLists.txt
@ -52,7 +52,7 @@
                                       ${CMAKE_CURRENT_SOURCE_DIR}/plugins/alpha/block/bigvia.py
                                       ${CMAKE_CURRENT_SOURCE_DIR}/plugins/alpha/block/spares.py
                                       ${CMAKE_CURRENT_SOURCE_DIR}/plugins/alpha/block/block.py
-                                       ${CMAKE_CURRENT_SOURCE_DIR}/plugins/alpha/block/clocktree.py
+                                       ${CMAKE_CURRENT_SOURCE_DIR}/plugins/alpha/block/htree.py
                                       ${CMAKE_CURRENT_SOURCE_DIR}/plugins/alpha/block/timing.py
                                       ${CMAKE_CURRENT_SOURCE_DIR}/plugins/alpha/block/rsmt.py
                                       ${CMAKE_CURRENT_SOURCE_DIR}/plugins/alpha/block/hfns1.py
--- a/cumulus/src/plugins/alpha/block/block.py
+++ b/cumulus/src/plugins/alpha/block/block.py
@ -16,6 +16,7 @@
 from   __future__ import print_function
 import sys
 import os.path
+from   copy      import deepcopy
 import Cfg
 from   Hurricane import Breakpoint, DbU, Box, Transformation, Point, \
                        Box, Path, Layer, Occurrence, Net,           \
@ -35,7 +36,7 @@ from   plugins                   import getParameter
 from   plugins.alpha.macro.macro         import Macro
 from   plugins.alpha.block               import timing
 from   plugins.alpha.block.spares        import Spares
-from   plugins.alpha.block.clocktree     import ClockTree
+from   plugins.alpha.block.htree         import HTree
 #from   plugins.alpha.block.hfns1         import BufferTree
 #from   plugins.alpha.block.hfns2         import BufferTree
 #from   plugins.alpha.block.hfns3         import BufferTree
@ -286,6 +287,7 @@ class Block ( object ):
    """

    LUT = {}
+    FLATTENED = 0x0001

    @staticmethod
    def lookup ( cell ):
@ -300,10 +302,11 @@ class Block ( object ):
        self.flags            = 0
        self.conf             = conf
        self.spares           = Spares( self )
-        self.clockTrees       = []
+        self.hTrees           = []
        self.hfnTrees         = []
        self.blockInstances   = []
        self.placeHolderCount = 0
+        self.excludedNets     = deepcopy( self.conf.hTreeNames )
        self.sides            = { IoPin.WEST  : Side( self.conf, IoPin.WEST  )
                                , IoPin.EAST  : Side( self.conf, IoPin.EAST  )
                                , IoPin.SOUTH : Side( self.conf, IoPin.SOUTH )
@ -329,7 +332,6 @@ class Block ( object ):
                   .format(self.conf.cell.getName()) )
        Block.LUT[ self.conf.cell ] = self

-
    @staticmethod
    def _getInstance ( cell, pattern, level=0 ):
        """
@ -370,6 +372,35 @@ class Block ( object ):
        """
        return Block._rgetInstance( self.conf.core, path )

+    @staticmethod
+    def _rinstancesToPath ( path, instances ):
+        instance = path.getTailInstance().getMasterCell().getInstance( instances[0] )
+        path     = Path( path, instance )
+        if len(instances) > 1:
+            return Block._rinstanceToPath( path, instances[1:] )
+        return path
+
+    @staticmethod
+    def _instancesToPath ( cell, instances ):
+        instance = cell.getInstance( instances[0] )
+        return Block._rinstancesToPath( Path(instance), instances[1:] )
+
+    def getFlattenedNet ( self, path ):
+        """
+        Find a net in the hierarchy. The path argument is a  list pathname of instance
+        endind by a net name, like "instance1.instance2.net_name". The function returns
+        a an Occurrence, the instance path and the Net, or None.
+        """
+        for net in self.conf.cellPnR.getNets():
+            if net.getName() == path:
+                return Occurrence( net, Path() )
+        elements = path.split('.')
+        if len(elements) == 1:
+            return None
+        path = Block._instancesToPath( self.conf.cellPnR, elements[:-1] )
+        net  = path.getTailInstance().getMasterCell().getNet( elements[-1] )
+        return Occurrence( net, path )
+
    def setUnexpandPins ( self, sides ):
        """
        Prevent Pins from the selected sides to be stick out of one pitch.
@ -433,43 +464,65 @@ class Block ( object ):
        else:
            self.conf.setRoutingBb( self.conf.cell.getAbutmentBox() )

-    def addClockTrees ( self ):
-        """Create the trunk of all the clock trees (recursive H-Tree)."""
-        print( '  o  Building clock tree(s).' )
-        af = CRL.AllianceFramework.get()
-        clockNets = []
-        for net in self.conf.cellPnR.getNets():
-            if af.isCLOCK(net.getName()): 'CLOCK: {}'.format(net)
-            if net.isClock():
-                trace( 550, '\tBlock.addClockTrees(): Found clock {}.\n'.format(net) )
-                clockNets.append( net )
-        if not clockNets:
-            raise ErrorMessage( 3, 'Block.clockTree(): Cell "{}" has no clock net(s).'.format(self.conf.cell.getName()) )
-        with UpdateSession():
-            for clockNet in clockNets:
-                print( '     - "{}".'.format(clockNet.getName()) )
-                trace( 550, ',+', '\tBlock.addClockTrees(): Build clock tree for {}.\n'.format(clockNet) )
-                self.clockTrees.append( ClockTree(self.spares,clockNet,len(self.clockTrees)) )
-                self.clockTrees[-1].buildHTree()
-                trace( 550, '-' )
-        Breakpoint.stop( 100, 'Block.addClockTrees() on {} done.'.format(self.conf.cellPnR) )
+    def flattenNets ( self ):
+        if self.flags & Block.FLATTENED: return
+        if self.conf.isCoreBlock:
+            self.conf.corona.flattenNets( self.conf.icore, self.conf.hTreeNames, Cell.Flags_NoClockFlatten )
+        else:
+            self.conf.cell.flattenNets( None, self.excludedNets, Cell.Flags_NoClockFlatten )
+        self.flags |= Block.FLATTENED

-    def splitClocks ( self ):
+    def addHTrees ( self ):
+        """Create the trunk of all the clock trees (recursive H-Tree)."""
+        print( '  o  Building H-Tree(s).' )
+        af = CRL.AllianceFramework.get()
+        hTreeNets = []
+        netOcc    = None
+        self.flattenNets()
+        for netName in self.conf.hTreeNames:
+            netOcc = self.getFlattenedNet( netName )
+           #if self.conf.isCoreBlock:
+           #    coreNet = self.conf.cell.getNet( netName )
+           #    if coreNet is not None:
+           #        trace( 550, '\tFound coreNet={}\n'.format(coreNet) )
+           #        for plug in self.conf.icore.getPlugs():
+           #            if plug.getMasterNet() == coreNet:
+           #                net = plug.getNet()
+           #                break
+           #else:
+           #    net = self.conf.cellPnR.getNet( netName )
+            if netOcc is None:
+                print( ErrorMessage( 3, 'Block.addHTrees(): Cell "{}" has no H-Tree net "{}".' \
+                                        .format( self.conf.cellPnR.getName(), netName )))
+                continue
+            trace( 550, '\tBlock.addHTrees(): Found H-Tree {}.\n'.format(netOcc) )
+            hTreeNets.append( netOcc )
+            self.etesian.exclude( netName )
+        with UpdateSession():
+            for hTreeNet in hTreeNets:
+                print( '     - "{}".'.format(hTreeNet.getName()) )
+                trace( 550, ',+', '\tBlock.addHTrees(): Build clock tree for {}.\n'.format(hTreeNet) )
+                self.hTrees.append( HTree(self.spares,hTreeNet,len(self.hTrees)) )
+                self.hTrees[-1].buildHTree()
+                for net in self.hTrees[-1].subNets:
+                    self.etesian.exclude( net.getName() )
+                    self.excludedNets.append( net.getName() )
+                trace( 550, '-' )
+        Breakpoint.stop( 100, 'Block.addHTrees() on {} done.'.format(self.conf.cellPnR) )
+
+    def splitHTrees ( self ):
        """
-        Break the clock net and attach all it's Pins to the closest leaf
+        Break the H-Tree root nets and attach all it's Pins to the closest leaf
        if the H-Tree.
        """
-        for clockTree in self.clockTrees:
-            clockTree.splitClock()
+        for hTree in self.hTrees:
+            hTree.splitNet()

    def findHfnTrees4 ( self ):
        """Perform simple HFNS, just break nets regardless of placement."""
        print( '  o  Building high fanout nets trees.' )
        if self.spares:
-            if self.conf.isCoreBlock:
-               self.conf.corona.flattenNets( self.conf.icore, Cell.Flags_NoClockFlatten )
-            else:
-               self.conf.cell.flattenNets( None, Cell.Flags_NoClockFlatten )
+            self.flattenNets()
            beginCount = self.conf.bufferConf.count
            maxSinks   = 10
            dots( 82
@ -578,7 +631,7 @@ class Block ( object ):
            for side in self.sides.values():
                side.expand()

-    def place ( self ):
+    def initEtesian ( self ):
        editor = self.conf.editor
        if self.conf.isCoreBlock:
            self.etesian = Etesian.EtesianEngine.create( self.conf.corona )
@ -588,9 +641,11 @@ class Block ( object ):
                Breakpoint.stop( 100, 'Block.place(), corona loaded.')
        else:
            self.etesian = Etesian.EtesianEngine.create( self.conf.cell )
+        self.etesian.getCell().flattenNets( None, self.excludedNets, Cell.Flags_NoClockFlatten )
+
+    def place ( self ):
        if self.conf.placeArea:
            self.etesian.setPlaceArea( self.conf.placeArea )
-        self.etesian.getCell().flattenNets( None, Cell.Flags_NoClockFlatten )
        if self.conf.useHFNS: self.etesian.doHFNS()
        self.etesian.place()
        Breakpoint.stop( 100, 'Placement done.' )
@ -738,6 +793,7 @@ class Block ( object ):
                blockInstance.block.build()
        if editor: editor.setCell( self.conf.cellPnR )
        self.conf.cfg.apply()
+        self.initEtesian()
        iteration = -1
        while True:
            iteration += 1
@ -748,14 +804,14 @@ class Block ( object ):
                self.checkIoPins()
            self.spares.build()
           #if self.conf.useHFNS:      self.findHfnTrees4()
-            if self.conf.useClockTree: self.addClockTrees()
+            self.addHTrees()
           #if self.conf.useHFNS:      self.addHfnBuffers()
            if editor: editor.fit()
           #Breakpoint.stop( 0, 'Clock tree(s) done.' )
            self.place()
           #if self.conf.useHFNS: self.findHfnTrees()
            break
-        if self.conf.useClockTree: self.splitClocks()
+        self.splitHTrees()
        self.spares.removeUnusedBuffers()
        self.etesian.toHurricane()
        self.etesian.flattenPower()
--- a/cumulus/src/plugins/alpha/block/configuration.py
+++ b/cumulus/src/plugins/alpha/block/configuration.py
@ -1109,6 +1109,7 @@ class BlockConf ( GaugeConf ):
        self.placeArea     = None
        self.deltaAb       = [ 0, 0, 0, 0 ]
        self.useClockTree  = False
+        self.hTreeNames    = [ ]
        self.useHFNS       = False
        self.useSpares     = True
        self.isBuilt       = False
@ -1210,6 +1211,10 @@ class BlockConf ( GaugeConf ):
            trace( 550, '\tNew cloned cell: "{}"\n'.format(masterCell) )
            self.cloneds.append( masterCell )
        return
+
+    def useHTree ( self, netName ):
+        if not netName in self.hTreeNames:
+            self.hTreeNames.append( netName );
  
    def save ( self, flags ):
        """
--- a/cumulus/src/plugins/alpha/block/clocktree.py
+++ b/cumulus/src/plugins/alpha/block/clocktree.py
@ -9,7 +9,7 @@
 # |  Author      :                    Jean-Paul CHAPUT              |
 # |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
 # | =============================================================== |
-# |  Python      :       "./plugins/block/clocktree.py"             |
+# |  Python      :       "./plugins/block/htree.py"                 |
 # +-----------------------------------------------------------------+


@ -17,29 +17,14 @@ from   __future__ import print_function
 import sys
 import os.path
 import Cfg
-from   Hurricane import Breakpoint
-from   Hurricane import DbU
-from   Hurricane import Box
-from   Hurricane import Transformation
-from   Hurricane import Box
-from   Hurricane import Path
-from   Hurricane import Layer
-from   Hurricane import Occurrence
-from   Hurricane import Net
-from   Hurricane import HyperNet
-from   Hurricane import RoutingPad
-from   Hurricane import Horizontal
-from   Hurricane import Vertical
-from   Hurricane import Contact
-from   Hurricane import Pin
-from   Hurricane import Plug
-from   Hurricane import Instance
+from   Hurricane import Breakpoint, DbU, Box, Transformation, Box, \
+                        Path, Layer, Occurrence, Net, HyperNet,    \
+                        RoutingPad, Horizontal, Vertical, Contact, \
+                        Pin, Plug, Instance
 import CRL
 from   CRL             import RoutingLayerGauge
 from   helpers         import trace
-from   helpers.io      import ErrorMessage
-from   helpers.io      import WarningMessage
-from   helpers.io      import catch
+from   helpers.io      import ErrorMessage, WarningMessage, catch
 from   helpers.overlay import UpdateSession
 from   plugins         import getParameter
 from   plugins.alpha   import utils
@ -48,33 +33,47 @@ from   plugins.alpha.block.spares        import Spares


 # ----------------------------------------------------------------------------
-# Class  :  "clocktree.ClockTree".
+# Class  :  "htree.HTree".

-class ClockTree ( object ):
+class HTree ( object ):
    """
-    Build a clock tree on a block.
+    Build a H-Tree on a net occurrene.
    """

-    def __init__ ( self, spares, clockNet, index ):
+    def __init__ ( self, spares, treeNetOcc, index ):
        self.spares     = spares
-        self.clockNet   = clockNet
-        self.clockIndex = index
+        self.treeNetOcc = treeNetOcc
+        self.treeIndex  = index
        self.subNets    = []
-        if not self.clockNet.isClock():
-            print( WarningMessage( 'ClockTree.__init__(): Net "{}" is not of CLOCK type.' \
-                                   .format(self.clockNet.getName()) ))
+       #if not self.treeNetOcc.getEntity().isClock():
+       #    print( WarningMessage( 'HTree.__init__(): Net "{}" is not of CLOCK type.' \
+       #                           .format(self.treeNet.getEntity().getName()) ))
+        if treeNetOcc.getPath().isEmpty():
+            self.treeNet = self.treeNetOcc.getEntity()
+        else:
+            botNet = self.treeNetOcc.getEntity()
+            botNet.setExternal( True )
+            topNetName = self.treeNetOcc.getName()
+            topNet     = Net.create( self.treeNetOcc.getPath().getOwnerCell(), topNetName )
+            topNet.setType     ( botNet.getType() )
+            topNet.setDirection( botNet.getDirection() )
+            path   = self.treeNetOcc.getPath().getHeadPath()
+            self.spares.raddTransNet( topNet, path )
+            botInstance = self.treeNetOcc.getPath().getTailInstance()
+            botInstance.getPlug( botNet ).setNet( botInstance.getCell().getNet( topNetName ))
+            self.treeNet = topNet

    def destroy ( self ):
-        trace( 550, ',+', '\tClockTree.destroy() "{}"\n'.format(self.clockNet.getName()) )
+        trace( 550, ',+', '\tHTree.destroy() "{}"\n'.format(self.treeNet.getName()) )
        with UpdateSession():
-            for subNet in self.subNets + [ self.clockNet ]:
+            for subNet in self.subNets + [ self.treeNet ]:
                components = []
                for comp in subNet.getComponents():
                    if isinstance(comp,RoutingPad): components.append( comp )
                    if isinstance(comp,Pin       ): components.append( comp )
                for comp in components:
                    comp.destroy()
-                if subNet != self.clockNet:
+                if subNet != self.treeNet:
                    subNet.destroy()
        trace( 550, '-' )

@ -82,7 +81,7 @@ class ClockTree ( object ):
        if qt.isLeaf(): return False
        qt.rconnectBuffer()
        driverNet = qt.bOutputPlug.getNet()
-        driverNet.setType( Net.Type.CLOCK )
+        driverNet.setType( self.treeNet.getType() )
        for leaf in qt.leafs:
            leaf.bInputPlug.setNet( driverNet )
            self._rconnectHTree( leaf )
@ -92,7 +91,7 @@ class ClockTree ( object ):
        """
        Recursively build one HTree branch for all non-terminal nodes of the QuadTree.
        """
-        trace( 550, ',+', '\tClockTree._rrouteHTree() {}\n'.format(qt.bOutputPlug.getNet()) )
+        trace( 550, ',+', '\tHTree._rrouteHTree() {}\n'.format(qt.bOutputPlug.getNet()) )
        trace( 550, '\tOn: {}\n'.format(qt) )
        if qt.isLeaf():
            trace( 550, '-' )
@ -165,13 +164,13 @@ class ClockTree ( object ):
            gaugeConf.setStackPosition( brContact, rightX, blY )
            gaugeConf.createVertical  ( rightContact, brContact, rightX, 0 )
        if qt.isRoot():
-            ckNet = self.clockNet
+            ckNet = self.treeNet
            if not self.spares.conf.isCoreBlock:
                trace( 550, '\tRemoving any previous pin...\n' )
                pins = []
                for pin in ckNet.getPins(): pins.append( pin )
                for pin in pins:
-                    print( WarningMessage('ClockTree._rrouteHTree(): Removing {}.'.format(pin)) )
+                    print( WarningMessage('HTree._rrouteHTree(): Removing {}.'.format(pin)) )
                    pin.destroy()
                layerGauge  = gaugeConf.vRoutingGauge
                rootContact = gaugeConf.rpAccessByPlugName( qt.buffer, bufferConf.input, ckNet, 0 )
@ -196,41 +195,44 @@ class ClockTree ( object ):
        
    def buildHTree ( self ):
        """
-        Create the clock tree netlist in two steps:
+        Create the tree tree netlist in two steps:
        1. Connect the buffers of the spares QuadTree to form a H-Tree.
-        2. Detach the all the clock sink point and reconnect them to the
+        2. Detach the all the tree sink point and reconnect them to the
           buffers of the leafs of the QuadTree.
        """
        qt           = self.spares.quadTree
-        qt.bufferTag = self.clockNet.getName()
-        qt.rselectBuffer( self.clockIndex, self.clockIndex, Spares.CHECK_USED|Spares.MARK_USED)
+        qt.bufferTag = self.treeNet.getName()
+        qt.rselectBuffer( self.treeIndex, self.treeIndex, Spares.CHECK_USED|Spares.MARK_USED)
        with UpdateSession():
            self._rconnectHTree( qt )
            self._rrouteHTree  ( qt )

-    def splitClock ( self ):
+    def splitNet ( self ):
        """
-        Disconnect the registers from the main clock and reconnect them to
-        the leaf buffers of the clock tree.
+        Disconnect the sinks from the main tree and reconnect them to
+        the leaf buffers of the tree tree.
        """
        bufferConf         = self.spares.conf.bufferConf
        quadTree           = self.spares.quadTree
-        quadTree.bufferTag = self.clockNet.getName()
-        quadTree.rselectBuffer( self.clockIndex, self.clockIndex, 0 )
+        quadTree.bufferTag = self.treeNet.getName()
+        quadTree.rselectBuffer( self.treeIndex, self.treeIndex, 0 )
        with UpdateSession():
-            coronaPlugs = []
-            hyperClock  = HyperNet.create( Occurrence(self.clockNet) )
-            for plugOccurrence in hyperClock.getTerminalNetlistPlugOccurrences():
-                if quadTree.isUnderArea(plugOccurrence):
-                    quadTree.attachToLeaf( plugOccurrence )
+            driverPlugs = []
+            hyperNet    = HyperNet.create( Occurrence(self.treeNet) )
+            for plugOcc in hyperNet.getTerminalNetlistPlugOccurrences():
+                trace( 550, '\tReattach "{}"\n'.format(plugOcc) )
+                plug = plugOcc.getEntity()
+                if not (plug.getMasterNet().getDirection() & Net.Direction.OUT) \
+                   and quadTree.isUnderArea(plugOcc):
+                    quadTree.attachToLeaf( plugOcc )
                else:
-                    coronaPlugs.append( plugOccurrence )
+                    driverPlugs.append( plugOcc )
            quadTree.rsplitNetlist()
            if self.spares.conf.isCoreBlock:
                plug = utils.getPlugByName( quadTree.buffer, bufferConf.input )
-                plug.setNet( self.clockNet )
-                trace( 550, '\tCore mode, setting only root plug "{}"\n'.format(self.clockNet.getName()) )
-                trace( 550, '\tPlug of "{}" (Cell:{})\n'.format(self.clockNet.getName()
-                                                               ,self.clockNet.getCell()) )
-                for plug in self.clockNet.getPlugs():
+                plug.setNet( self.treeNet )
+                trace( 550, '\tCore mode, setting only root plug "{}"\n'.format(self.treeNet.getName()) )
+                trace( 550, '\tPlug of "{}" (Cell:{})\n'.format(self.treeNet.getName()
+                                                               ,self.treeNet.getCell()) )
+                for plug in self.treeNet.getPlugs():
                    trace( 550, '\t| {}\n'.format(plug) )
--- a/cumulus/src/plugins/alpha/chip/chip.py
+++ b/cumulus/src/plugins/alpha/chip/chip.py
@ -120,7 +120,7 @@ class Chip ( Block ):
        if self.conf.routingGauge.hasPowerSupply():
            power = plugins.alpha.chip.powerplane.Builder( self.conf )
            power.connectPower()
-            power.connectClocks()
+            power.connectHTrees( self.hTrees )
            power.doLayout()
            Breakpoint.stop( 101, 'After Query power.' )
        else:
--- a/cumulus/src/plugins/alpha/chip/powerplane.py
+++ b/cumulus/src/plugins/alpha/chip/powerplane.py
@ -455,23 +455,23 @@ class Builder ( object ):
            trace( 550, '-' )
        self.activePlane = None
  
-    def _connectClock ( self, ck, trackNb ):
-        trace( 550, '\tpower.Builder._connectClock() {}\n'.format(ck) )
-        blockCk = None
+    def _connectHTree ( self, coronaNet, trackNb ):
+        trace( 550, '\tpower.Builder._connectHTree() {} on track {}\n'.format(coronaNet,trackNb) )
+        coreNet = None
        for plug in self.conf.icore.getPlugs():
-            if plug.getNet() == ck:
-                blockCk = plug.getMasterNet()
-        if not blockCk:
-            raise ErrorMessage( 1, 'Block "{}" has no net connected to the clock "{}".' \
-                                   .format(self.conf.icore.getName(),ck.getName()) )
+            if plug.getNet() == coronaNet:
+                coreNet = plug.getMasterNet()
+        if not coreNet:
+            raise ErrorMessage( 1, 'Block "{}" has no net connected to the H-Tree "{}".' \
+                                   .format(self.conf.icore.getName(),coronaNet.getName()) )
            return
        htPlugs = []
-        for plug in ck.getPlugs():
+        for plug in coronaNet.getPlugs():
            if plug.getInstance().isTerminalNetlist():
                htPlugs.append( plug )
        if len(htPlugs) != 1:
-            message = [ 'Clock "{}" of block "{}" is not organized as a H-Tree ({} plugs).' \
-                        .format( ck.getName()
+            message = [ 'Net "{}" of block "{}" is not organized as a H-Tree ({} plugs).' \
+                        .format( coronaNet.getName()
                               , self.conf.icore.getName()
                               , len(htPlugs)) ]
            for plug in htPlugs:
@ -479,17 +479,17 @@ class Builder ( object ):
            raise ErrorMessage( 1, message )
            return
        coronaPin = None
-        for pin in ck.getPins():
+        for pin in coronaNet.getPins():
            coronaPin = pin
            break
        if not coronaPin:
-            message = [ 'Clock "{}" of block "{}" is not connected to a corona Pin.' \
-                        .format( ck.getName() , self.conf.icore.getName() ) ]
+            message = [ 'Net "{}" of block "{}" is not connected to a corona Pin.' \
+                        .format( coronaNet.getName() , self.conf.icore.getName() ) ]
            raise ErrorMessage( 1, message )
        with UpdateSession():
            coronaAb   = self.conf.cellPnR.getAbutmentBox()
-            bufferRp   = self.conf.rpAccessByOccurrence( Occurrence(htPlugs[0], Path()), ck, 0 )
-            pinRp      = self.conf.rpAccessByOccurrence( Occurrence(coronaPin , Path()), ck, 0 )
+            bufferRp   = self.conf.rpAccessByOccurrence( Occurrence(htPlugs[0], Path()), coronaNet, 0 )
+            pinRp      = self.conf.rpAccessByOccurrence( Occurrence(coronaPin , Path()), coronaNet, 0 )
            trace( 550, '\tpinRp={}\n'.format(pinRp) )
            self.conf.expandMinArea( bufferRp )
            self.conf.expandMinArea( pinRp )
@ -508,40 +508,39 @@ class Builder ( object ):
                isVertical = False
                axis       = coronaAb.getXMin()
            if isVertical:
-                pitch    = self.conf.vRoutingGauge.getPitch()
-                yaxis    = axis + pitch * trackNb
+                pitch    = self.conf.hRoutingGauge.getPitch()
+                yaxis    = axis + 2 * pitch * trackNb
+                trace( 550, '\tyaxis(request)={}\n'.format(DbU.getValueString(yaxis)) )
                yaxis    = self.conf.getNearestHorizontalTrack( yaxis, 0 )
                xaxisRp  = self.conf.getNearestVerticalTrack( bufferRp.getX(), 0 )
                xaxisPin = self.conf.getNearestVerticalTrack( pin.getX(), 0 )
-                contact1 = self.conf.createContact( ck, xaxisRp , yaxis, 0 )
-                contact2 = self.conf.createContact( ck, xaxisPin, yaxis, 0 )
+                contact1 = self.conf.createContact( coronaNet, xaxisRp , yaxis, 0 )
+                contact2 = self.conf.createContact( coronaNet, xaxisPin, yaxis, 0 )
                self.conf.createVertical  ( bufferRp, contact1, xaxisRp , 0 )
                self.conf.createHorizontal( contact1, contact2, yaxis   , 0 )
                self.conf.createVertical  ( contact2, pinRp   , xaxisPin, 0 )
+                trace( 550, '\tyaxis(track)={}\n'.format(DbU.getValueString(yaxis)) )
                trace( 550, '\tcontact1={}\n'.format(contact1) )
                trace( 550, '\tcontact2={}\n'.format(contact2) )
            else:
-                pitch    = self.conf.hRoutingGauge.getPitch()
-                xaxis    = axis + pitch * trackNb
+                pitch    = self.conf.vRoutingGauge.getPitch()
+                xaxis    = axis + 2 * pitch * trackNb
+                trace( 550, '\txaxis(request)={} vpitch={}\n' \
+                            .format(DbU.getValueString(xaxis), DbU.getValueString(pitch)) )
                xaxis    = self.conf.getNearestVerticalTrack( xaxis, 0 )
                yaxisRp  = self.conf.getNearestHorizontalTrack( bufferRp.getY(), 0 )
                yaxisPin = self.conf.getNearestHorizontalTrack( pin.getY(), 0 )
-                contact1 = self.conf.createContact( ck, xaxis, yaxisRp , 0 )
-                contact2 = self.conf.createContact( ck, xaxis, yaxisPin, 0 )
+                contact1 = self.conf.createContact( coronaNet, xaxis, yaxisRp , 0 )
+                contact2 = self.conf.createContact( coronaNet, xaxis, yaxisPin, 0 )
                self.conf.createHorizontal( bufferRp, contact1, yaxisRp , 0 )
                self.conf.createVertical  ( contact1, contact2, xaxis   , 0 )
                self.conf.createHorizontal( contact2, pinRp   , yaxisPin, 0 )
+                trace( 550, '\txaxis(track)={}\n'.format(DbU.getValueString(xaxis)) )
        return
  
-    def connectClocks ( self ):
-        if not self.conf.useClockTree:
-            print( WarningMessage( "Clock tree generation has been disabled ('chip.clockTree':False)." ))
-            return
-        if len(self.conf.coronaCks) == 0:
-            raise ErrorMessage( 1, 'Cannot build clock terminal as no clock is not known.' )
-            return
-        for i in range(len(self.conf.coronaCks)):
-            self._connectClock( self.conf.coronaCks[i], i+2 )
+    def connectHTrees ( self, hTrees ):
+        for i in range(len(hTrees)):
+            self._connectHTree( hTrees[i].treeNet, i+2 )
  
    def doLayout ( self ):
        with UpdateSession():
--- a/etesian/src/EtesianEngine.cpp
+++ b/etesian/src/EtesianEngine.cpp
@ -323,6 +323,7 @@ namespace Etesian {
    , _fixedAbWidth (0)
    , _diodeCount   (0)
    , _bufferCount  (0)
+    , _excludedNets ()
  { }


@ -792,7 +793,7 @@ namespace Etesian {
    cmess1 << "     - Building RoutingPads (transhierarchical)" << endl;
  //getCell()->flattenNets( Cell::Flags::BuildRings|Cell::Flags::NoClockFlatten );
  //getCell()->flattenNets( getBlockInstance(), Cell::Flags::NoClockFlatten );
-    getCell()->flattenNets( NULL, Cell::Flags::NoClockFlatten );
+    getCell()->flattenNets( NULL, _excludedNets, Cell::Flags::NoClockFlatten );

    bool    tooManyInstances = false;
    index_t instanceId       = 0;
@ -929,9 +930,10 @@ namespace Etesian {
    for ( Net* net : getCell()->getNets() )
    {
      const char* excludedType = NULL;
-      if (net->getType() == Net::Type::POWER ) excludedType = "POWER";
-      if (net->getType() == Net::Type::GROUND) excludedType = "GROUND";
-      if (net->getType() == Net::Type::CLOCK ) excludedType = "CLOCK";
+      if (net->getType() == Net::Type::POWER )   excludedType = "POWER";
+      if (net->getType() == Net::Type::GROUND)   excludedType = "GROUND";
+      if (net->getType() == Net::Type::CLOCK )   excludedType = "CLOCK";
+      if (isExcluded(getString(net->getName()))) excludedType = "USER_EXCLUDED";
      if (excludedType) {
        cparanoid << Warning( "%s is not a routable net (%s,excluded)."
                            , getString(net).c_str(), excludedType ) << endl;
@ -952,9 +954,10 @@ namespace Etesian {
    for ( Net* net : getCell()->getNets() )
    {
      const char* excludedType = NULL;
-      if (net->getType() == Net::Type::POWER ) excludedType = "POWER";
-      if (net->getType() == Net::Type::GROUND) excludedType = "GROUND";
-      if (net->getType() == Net::Type::CLOCK ) excludedType = "CLOCK";
+      if (net->getType() == Net::Type::POWER )   excludedType = "POWER";
+      if (net->getType() == Net::Type::GROUND)   excludedType = "GROUND";
+      if (net->getType() == Net::Type::CLOCK )   excludedType = "CLOCK";
+      if (isExcluded(getString(net->getName()))) excludedType = "USER_EXCLUDED";
      if (excludedType) continue;
      if (af->isBLOCKAGE(net->getName())) continue;

--- a/etesian/src/HFNS.cpp
+++ b/etesian/src/HFNS.cpp
@ -456,6 +456,8 @@ namespace Etesian {
    BufferDatas* bufferDatas = getBufferCells().getBiggestBuffer();
    vector< tuple<Net*,uint32_t> > netDatas;
    for ( Net* net : getCell()->getNets() ) {
+      if (isExcluded(getString(net->getName()))) continue;
+      
      uint32_t rpCount = 0;
      for ( RoutingPad* rp : net->getRoutingPads() ) {
        Occurrence rpOcc = rp->getPlugOccurrence();
--- a/etesian/src/PyEtesianEngine.cpp
+++ b/etesian/src/PyEtesianEngine.cpp
@ -77,13 +77,14 @@ extern "C" {
  DirectVoidMethod(EtesianEngine,etesian,clearColoquinte)
  DirectVoidMethod(EtesianEngine,etesian,flattenPower)
  DirectVoidMethod(EtesianEngine,etesian,toHurricane)
-  DirectGetUIntAttribute  (PyEtesianEngine_doHFNS          ,doHFNS          ,PyEtesianEngine,EtesianEngine)
-  DirectSetLongAttribute  (PyEtesianEngine_setFixedAbHeight,setFixedAbHeight,PyEtesianEngine,EtesianEngine)
-  DirectSetLongAttribute  (PyEtesianEngine_setFixedAbWidth ,setFixedAbWidth ,PyEtesianEngine,EtesianEngine)
-  DirectSetDoubleAttribute(PyEtesianEngine_setSpaceMargin  ,setSpaceMargin  ,PyEtesianEngine,EtesianEngine)
-  DirectSetDoubleAttribute(PyEtesianEngine_setAspectRatio  ,setAspectRatio  ,PyEtesianEngine,EtesianEngine)
-  DirectGetLongAttribute  (PyEtesianEngine_getFixedAbHeight,getFixedAbHeight,PyEtesianEngine,EtesianEngine)
-  DirectGetLongAttribute  (PyEtesianEngine_getFixedAbWidth ,getFixedAbWidth ,PyEtesianEngine,EtesianEngine)
+  DirectGetUIntAttribute   (PyEtesianEngine_doHFNS          ,doHFNS          ,PyEtesianEngine,EtesianEngine)
+  DirectSetLongAttribute   (PyEtesianEngine_setFixedAbHeight,setFixedAbHeight,PyEtesianEngine,EtesianEngine)
+  DirectSetLongAttribute   (PyEtesianEngine_setFixedAbWidth ,setFixedAbWidth ,PyEtesianEngine,EtesianEngine)
+  DirectSetDoubleAttribute (PyEtesianEngine_setSpaceMargin  ,setSpaceMargin  ,PyEtesianEngine,EtesianEngine)
+  DirectSetDoubleAttribute (PyEtesianEngine_setAspectRatio  ,setAspectRatio  ,PyEtesianEngine,EtesianEngine)
+  DirectGetLongAttribute   (PyEtesianEngine_getFixedAbHeight,getFixedAbHeight,PyEtesianEngine,EtesianEngine)
+  DirectGetLongAttribute   (PyEtesianEngine_getFixedAbWidth ,getFixedAbWidth ,PyEtesianEngine,EtesianEngine)
+  DirectSetCStringAttribute(PyEtesianEngine_exclude         ,exclude         ,PyEtesianEngine,EtesianEngine)


  static PyObject* PyEtesianEngine_get ( PyObject*, PyObject* args )
@ -236,6 +237,8 @@ extern "C" {
                            , "Returns the Etesian engine attached to the Cell, None if there isn't." }
    , { "create"            , (PyCFunction)PyEtesianEngine_create            , METH_VARARGS|METH_STATIC
                            , "Create an Etesian engine on this cell." }
+    , { "exclude"           , (PyCFunction)PyEtesianEngine_exclude           , METH_VARARGS
+                            , "Add the specified net to the exclusion list." }
    , { "getFixedAbHeight"  , (PyCFunction)PyEtesianEngine_getFixedAbHeight  , METH_NOARGS
                            , "Returns the forced abutment box height." }
    , { "getFixedAbWidth"   , (PyCFunction)PyEtesianEngine_getFixedAbWidth   , METH_NOARGS
--- a/etesian/src/etesian/EtesianEngine.h
+++ b/etesian/src/etesian/EtesianEngine.h
@ -71,11 +71,13 @@ namespace Etesian {
      typedef std::tuple<Instance*, std::vector<RoutingPad*> > InstanceInfos;
      typedef std::map<Instance*,size_t,DBo::CompareById>      InstancesToIds;
      typedef std::map<Net*,size_t,DBo::CompareById>           NetsToIds;
+      typedef std::set<std::string>                            NetNameSet;
    public:
      static  const Name&            staticGetName             ();
      static  EtesianEngine*         create                    ( Cell* );
      static  EtesianEngine*         get                       ( const Cell* );
    public:                                                    
+      inline  bool                   isExcluded                ( std::string ) const;
      virtual Configuration*         getConfiguration          ();
      virtual const Configuration*   getConfiguration          () const;
      virtual const Name&            getName                   () const;
@ -106,6 +108,7 @@ namespace Etesian {
      inline  void                   setViewer                 ( Hurricane::CellViewer* );
      inline  Cell*                  getBlockCell              () const;
      inline  Instance*              getBlockInstance          () const;
+      inline  const NetNameSet&      getExcludedNets           () const;
      inline  void                   setBlock                  ( Instance* );
      inline  void                   setFixedAbHeight          ( DbU::Unit );
      inline  void                   setFixedAbWidth           ( DbU::Unit );
@ -136,6 +139,7 @@ namespace Etesian {
              uint32_t               doHFNS                    ();
      inline  void                   useFeed                   ( Cell* );
              size_t                 findYSpin                 ();
+      inline  void                   exclude                   ( string netName );
              void                   addFeeds                  ();
              void                   toHurricane               ();
              void                   flattenPower              ();
@ -174,6 +178,7 @@ namespace Etesian {
             DbU::Unit                            _fixedAbWidth;
             uint32_t                             _diodeCount;
             uint32_t                             _bufferCount;
+             NetNameSet                           _excludedNets;

    protected:
    // Constructors & Destructors.
@ -229,6 +234,8 @@ namespace Etesian {
  inline  uint32_t               EtesianEngine::_getNewDiodeId            () { return _diodeCount++; }
  inline  const Box&             EtesianEngine::getPlaceArea              () const { return _placeArea; }
  inline  Area*                  EtesianEngine::getArea                   () const { return _area; }
+  inline  const EtesianEngine::NetNameSet&
+                                 EtesianEngine::getExcludedNets           () const { return _excludedNets; }

  inline  void  EtesianEngine::setBlock ( Instance* block )
  {
@ -319,6 +326,24 @@ namespace Etesian {
  }


+  inline  bool  EtesianEngine::isExcluded ( string netName ) const
+  { return (_excludedNets.find(netName) != _excludedNets.end()); }
+
+
+  inline  void  EtesianEngine::exclude ( string netName )
+  {
+    // Net* net = getCell()->getNet( netName );
+    // if (not net) {
+    //   std::cerr << Error( "EtesianEngine::exclude(Net*): %s has no net named \"%s\"."
+    //                     , getString(getCell()).c_str()
+    //                     , netName.c_str()
+    //                     ) << std::endl;
+    //   return;
+    // }
+    if (isExcluded(netName)) return;
+    _excludedNets.insert( netName );
+  }
+
 // Variables.
  extern const char* missingEtesian;

--- a/hurricane/src/hurricane/Cell.cpp
+++ b/hurricane/src/hurricane/Cell.cpp
@ -820,6 +820,13 @@ void Cell::flattenNets (uint64_t flags )

 void Cell::flattenNets ( const Instance* instance, uint64_t flags )
 // ****************************************************************
+{
+  static set<string> excludeds;
+  flattenNets( instance, excludeds, flags );
+}
+
+void Cell::flattenNets ( const Instance* instance, const std::set<string>& excludeds, uint64_t flags )
+// ***************************************************************************************************
 {
  cdebug_log(18,1) << "Cell::flattenNets() flags:0x" << hex << flags << endl;

@ -837,6 +844,7 @@ void Cell::flattenNets ( const Instance* instance, uint64_t flags )

    if (net->isClock() and (flags & Flags::NoClockFlatten)) continue;
    if (net->isPower() or net->isGround() or net->isBlockage()) continue;
+    if (excludeds.find(getString(occurrence.getName())) != excludeds.end()) continue;

    HyperNet  hyperNet ( occurrence );
    if ( not occurrence.getPath().isEmpty() ) {
--- a/hurricane/src/hurricane/Net.cpp
+++ b/hurricane/src/hurricane/Net.cpp
@ -728,9 +728,6 @@ void Net::_preDestroy()
 // *******************
 {
  cdebug_log(18,1) << "entering Net::_preDestroy: " << this << endl;
-  if (getName() == "pipe_middle_0_rb[0]")
-    cerr << "entering Net::_preDestroy: " << this << endl;
-
  Inherit::_preDestroy();

  cdebug_log(18,0) << "Net::_preDestroy: " << this << " slave Plugs..." << endl;
--- a/hurricane/src/hurricane/hurricane/Cell.h
+++ b/hurricane/src/hurricane/hurricane/Cell.h
@ -507,6 +507,7 @@ class Cell : public Entity {
    public: void setAbstractedSupply(bool state) { _flags.set(Flags::AbstractedSupply,state); };
    public: void flattenNets(uint64_t flags=Flags::BuildRings);
    public: void flattenNets(const Instance* instance, uint64_t flags=Flags::BuildRings);
+    public: void flattenNets(const Instance* instance, const std::set<std::string>& excludeds, uint64_t flags=Flags::BuildRings);
    public: void createRoutingPadRings(uint64_t flags=Flags::BuildRings);
    public: void setFlags(uint64_t flags) { _flags |= flags; }
    public: void resetFlags(uint64_t flags) { _flags &= ~flags; }
--- a/hurricane/src/isobar/PyCell.cpp
+++ b/hurricane/src/isobar/PyCell.cpp
@ -29,6 +29,24 @@

 namespace  Isobar {

+  
+  bool  pyListToStringSet ( PyObject* list, set<string>& v )
+  {
+    if (not PyList_Check(list)) return false;
+
+    int length = PyList_Size( list );
+    for ( int i=0 ; i<length ; ++i ) {
+      PyObject* item = PyList_GetItem( list, i );
+      if (not PyString_Check(item)) {
+        string message =  "pyListToStringSet: Item at position " + getString(i) + " is not a string.";
+        PyErr_SetString( ConstructorError, message.c_str() );
+        return false;
+      }
+      v.insert( PyString_AsString(item) );
+    }
+    return true;
+  }
+

 using namespace Hurricane;

@ -730,30 +748,36 @@ extern "C" {
  {
    cdebug_log(20,0) << "PyCell_flattenNets()" << endl;
    
-    Instance* instance = NULL;
-    PyObject* arg0     = NULL;
-    PyObject* arg1     = NULL;
+    uint64_t     flags    = 0;
+    set<string>  excludeds;
+    Instance*    instance = NULL;
+    PyObject*    arg0     = NULL;
+    PyObject*    arg1     = NULL;
+    PyObject*    arg2     = NULL;

    HTRY
      METHOD_HEAD ( "Cell.flattenNets()" )
      __cs.init( "Cell.flattenNets" );
-      if (not PyArg_ParseTuple(args,"O&O&:Cell.flattenNets"
-                              ,Converter,&arg0
-                              ,Converter,&arg1
-                              )) {
-          PyErr_SetString( ConstructorError, "Cell.flattenNets(): Takes exactly two parameters." );
-          return NULL;
-      }
-  
-      if (arg0 == Py_None) {
-        cell->flattenNets( NULL, PyInt_AsLong(arg1) );
-      } else if (__cs.getObjectIds() == ":ent:int") {
-        cell->flattenNets( PYINSTANCE_O(arg0), PyInt_AsLong(arg1) );
-      } else {
-        string message = "Cell.flattenNets(): Bad type of parameter(s), \"" + __cs.getObjectIds() + "\".";
-        PyErr_SetString( ConstructorError, message.c_str() );
+      if (not PyArg_ParseTuple(args,"OO|O:Cell.flattenNets", &arg0, &arg1, &arg2 )) {
+        PyErr_SetString( ConstructorError, "Cell.flattenNets(): Takes between two and three parameters." );
        return NULL;
      }
+  
+      if (arg0 != Py_None) {
+        if (not IsPyInstance(arg0)) {
+          PyErr_SetString( ConstructorError, "Cell.flattenNets(): First argument must be None or an Instance." );
+          return NULL;
+        }
+        instance = PYINSTANCE_O( arg0 );
+      }
+      if (arg2) {
+        pyListToStringSet( arg1, excludeds );
+        flags = PyInt_AsLong( arg2 );
+      } else {
+        flags = PyInt_AsLong( arg1 );
+      }
+
+      cell->flattenNets( instance, excludeds, flags );
    HCATCH
    Py_RETURN_NONE;
  }