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diff --git a/src/opt/lpk/lpkAbcMux.c b/src/opt/lpk/lpkAbcMux.c
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+/**CFile****************************************************************
+
+  FileName    [lpkAbcMux.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Fast Boolean matching for LUT structures.]
+
+  Synopsis    [Iterative MUX decomposition.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - April 28, 2007.]
+
+  Revision    [$Id: lpkAbcMux.c,v 1.00 2007/04/28 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "lpkInt.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Computes cofactors w.r.t. the given var.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Lpk_FunComputeCofs( Lpk_Fun_t * p, int iVar )
+{
+    unsigned * pTruth  = Lpk_FunTruth( p, 0 );
+    unsigned * pTruth0 = Lpk_FunTruth( p, 1 );
+    unsigned * pTruth1 = Lpk_FunTruth( p, 2 );
+    Kit_TruthCofactor0New( pTruth0, pTruth, p->nVars, iVar );
+    Kit_TruthCofactor1New( pTruth1, pTruth, p->nVars, iVar );
+}
+
+
+/**Function*************************************************************
+
+  Synopsis    [Computes cofactors w.r.t. each variable.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Lpk_FunComputeCofSupps( Lpk_Fun_t * p, unsigned * puSupps )
+{
+    unsigned * pTruth  = Lpk_FunTruth( p, 0 );
+    unsigned * pTruth0 = Lpk_FunTruth( p, 1 );
+    unsigned * pTruth1 = Lpk_FunTruth( p, 2 );
+    int Var;
+    Lpk_SuppForEachVar( p->uSupp, Var )
+    {
+        Lpk_FunComputeCofs( p, Var );
+        puSupps[2*Var+0] = Kit_TruthSupport( pTruth0, p->nVars );
+        puSupps[2*Var+1] = Kit_TruthSupport( pTruth1, p->nVars );
+    }
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Checks the possibility of MUX decomposition.]
+
+  Description [Returns the best variable to use for MUX decomposition.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Lpk_FunAnalizeMux( Lpk_Fun_t * p )
+{
+    unsigned puSupps[32] = {0};
+    int nSuppSize0, nSuppSize1, Delay, Delay0, Delay1, DelayA, DelayB;
+    int Var, Area, Polarity, VarBest, AreaBest, PolarityBest, nSuppSizeBest;
+
+    if ( p->nVars > p->nAreaLim * (p->nLutK - 1) + 1 )
+        return -1;
+    // get cofactor supports for each variable
+    Lpk_FunComputeCofSupps( p, puSupps );
+    // derive the delay and area of each MUX-decomposition
+    VarBest = -1;
+    Lpk_SuppForEachVar( p->uSupp, Var )
+    {
+        nSuppSize0 = Kit_WordCountOnes(puSupps[2*Var+0]);
+        nSuppSize1 = Kit_WordCountOnes(puSupps[2*Var+1]);
+        if ( nSuppSize0 <= (int)p->nLutK - 2 && nSuppSize1 <= (int)p->nLutK - 2 )
+        {
+            // include cof var into 0-block
+            DelayA = Lpk_SuppDelay( puSupps[2*Var+0] | (1<<Var), p->pDelays );
+            DelayB = Lpk_SuppDelay( puSupps[2*Var+1]           , p->pDelays );
+            Delay0 = ABC_MAX( DelayA, DelayB + 1 );
+            // include cof var into 1-block
+            DelayA = Lpk_SuppDelay( puSupps[2*Var+1] | (1<<Var), p->pDelays );
+            DelayB = Lpk_SuppDelay( puSupps[2*Var+0]           , p->pDelays );
+            Delay1 = ABC_MAX( DelayA, DelayB + 1 );
+            // get the best delay
+            Delay = ABC_MIN( Delay0, Delay1 );
+            Area = 2;
+            Polarity = (int)(Delay1 == Delay);
+        }
+        else if ( nSuppSize0 <= (int)p->nLutK - 2 )
+        {
+            DelayA = Lpk_SuppDelay( puSupps[2*Var+0] | (1<<Var), p->pDelays );
+            DelayB = Lpk_SuppDelay( puSupps[2*Var+1]           , p->pDelays );
+            Delay = ABC_MAX( DelayA, DelayB + 1 );
+            Area = 1 + Lpk_LutNumLuts( nSuppSize1, p->nLutK );
+            Polarity = 0;
+        }
+        else if ( nSuppSize0 <= (int)p->nLutK )
+        {
+            DelayA = Lpk_SuppDelay( puSupps[2*Var+1] | (1<<Var), p->pDelays );
+            DelayB = Lpk_SuppDelay( puSupps[2*Var+0]           , p->pDelays );
+            Delay = ABC_MAX( DelayA, DelayB + 1 );
+            Area = 1 + Lpk_LutNumLuts( nSuppSize1+2, p->nLutK );
+            Polarity = 1;
+        }
+        else if ( nSuppSize1 <= (int)p->nLutK - 2 )
+        {
+            DelayA = Lpk_SuppDelay( puSupps[2*Var+1] | (1<<Var), p->pDelays );
+            DelayB = Lpk_SuppDelay( puSupps[2*Var+0]           , p->pDelays );
+            Delay = ABC_MAX( DelayA, DelayB + 1 );
+            Area = 1 + Lpk_LutNumLuts( nSuppSize0, p->nLutK );
+            Polarity = 1;
+        }
+        else if ( nSuppSize1 <= (int)p->nLutK )
+        {
+            DelayA = Lpk_SuppDelay( puSupps[2*Var+0] | (1<<Var), p->pDelays );
+            DelayB = Lpk_SuppDelay( puSupps[2*Var+1]           , p->pDelays );
+            Delay = ABC_MAX( DelayA, DelayB + 1 );
+            Area = 1 + Lpk_LutNumLuts( nSuppSize0+2, p->nLutK );
+            Polarity = 0;
+        }
+        else
+        {
+            // include cof var into 0-block
+            DelayA = Lpk_SuppDelay( puSupps[2*Var+0] | (1<<Var), p->pDelays );
+            DelayB = Lpk_SuppDelay( puSupps[2*Var+1]           , p->pDelays );
+            Delay0 = ABC_MAX( DelayA, DelayB + 1 );
+            // include cof var into 1-block
+            DelayA = Lpk_SuppDelay( puSupps[2*Var+1] | (1<<Var), p->pDelays );
+            DelayB = Lpk_SuppDelay( puSupps[2*Var+0]           , p->pDelays );
+            Delay1 = ABC_MAX( DelayA, DelayB + 1 );
+            // get the best delay
+            Delay = ABC_MIN( Delay0, Delay1 );
+            if ( Delay == Delay0 )
+                Area = Lpk_LutNumLuts( nSuppSize0+2, p->nLutK ) + Lpk_LutNumLuts( nSuppSize1, p->nLutK );
+            else
+                Area = Lpk_LutNumLuts( nSuppSize1+2, p->nLutK ) + Lpk_LutNumLuts( nSuppSize0, p->nLutK );
+            Polarity = (int)(Delay1 == Delay);
+        }
+        // find the best variable
+        if ( Delay > (int)p->nDelayLim )
+            continue;
+        if ( Area > (int)p->nAreaLim )
+            continue;
+        if ( VarBest == -1 || AreaBest > Area || (AreaBest == Area && nSuppSizeBest > nSuppSize0+nSuppSize1) )
+        {
+            VarBest = Var;
+            AreaBest = Area;
+            PolarityBest = Polarity;
+            nSuppSizeBest = nSuppSize0+nSuppSize1;
+        }
+    }
+    return (VarBest == -1)? -1 : (2*VarBest + Polarity);
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Transforms the function decomposed by the MUX decomposition.]
+
+  Description [Returns the best variable to use for MUX decomposition.]
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Lpk_Fun_t * Lpk_FunSplitMux( Lpk_Fun_t * p, int VarPol )
+{
+    Lpk_Fun_t * pNew;
+    unsigned * pTruth  = Lpk_FunTruth( p, 0 );
+    unsigned * pTruth0 = Lpk_FunTruth( p, 1 );
+    unsigned * pTruth1 = Lpk_FunTruth( p, 2 );
+    int Var = VarPol / 2;
+    int Pol = VarPol % 2;
+    int iVarVac;
+    assert( VarPol >= 0 && VarPol < 2 * (int)p->nVars );
+    assert( p->nAreaLim >= 2 );
+    Lpk_FunComputeCofs( p, Var );
+    if ( Pol == 0 )
+    {
+        // derive the new component
+        pNew = Lpk_FunDup( p, pTruth1 );
+        // update the old component
+        p->uSupp = Kit_TruthSupport( pTruth0, p->nVars );
+        iVarVac = Kit_WordFindFirstBit( ~(p->uSupp | (1 << Var)) );
+        assert( iVarVac < (int)p->nVars );
+        Kit_TruthIthVar( pTruth, p->nVars, iVarVac );
+        // update the truth table
+        Kit_TruthMux( pTruth, pTruth0, pTruth1, pTruth, p->nVars );
+        p->pFanins[iVarVac] = pNew->Id;
+        p->pDelays[iVarVac] = Lpk_SuppDelay( pNew->uSupp, pNew->pDelays );
+        // support minimize both
+        Lpk_FunSuppMinimize( p );
+        Lpk_FunSuppMinimize( pNew );
+        // update delay and area requirements
+        pNew->nDelayLim = p->nDelayLim - 1;
+        if ( p->nVars <= p->nLutK )
+        {
+            pNew->nAreaLim = p->nAreaLim - 1;
+            p->nAreaLim = 1;
+        }
+        else if ( pNew->nVars <= pNew->nLutK )
+        {
+            pNew->nAreaLim = 1;
+            p->nAreaLim = p->nAreaLim - 1;
+        }
+        else if ( p->nVars < pNew->nVars )
+        {
+            pNew->nAreaLim = p->nAreaLim / 2 + p->nAreaLim % 2;
+            p->nAreaLim = p->nAreaLim / 2 - p->nAreaLim % 2;
+        }
+        else // if ( pNew->nVars < p->nVars )
+        {
+            pNew->nAreaLim = p->nAreaLim / 2 - p->nAreaLim % 2;
+            p->nAreaLim = p->nAreaLim / 2 + p->nAreaLim % 2;
+        }
+    }
+    return p;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+