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/**CFile****************************************************************
FileName [abcBalance.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Network and node package.]
Synopsis [Performs global balancing of the AIG by the number of levels.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: abcBalance.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "abc.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
static void Abc_NtkBalancePerform( Abc_Ntk_t * pNtk, Abc_Ntk_t * pNtkAig, bool fDuplicate );
static Abc_Obj_t * Abc_NodeBalance_rec( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pNode, bool fDuplicate );
static Vec_Ptr_t * Abc_NodeBalanceCone( Abc_Obj_t * pNode, int fDuplicate );
static int Abc_NodeBalanceCone_rec( Abc_Obj_t * pNode, Vec_Ptr_t * vSuper, bool fFirst, bool fDuplicate );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Balances the AIG network.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Ntk_t * Abc_NtkBalance( Abc_Ntk_t * pNtk, bool fDuplicate )
{
int fCheck = 1;
Abc_Ntk_t * pNtkAig;
assert( Abc_NtkIsStrash(pNtk) );
// perform balancing
pNtkAig = Abc_NtkStartFrom( pNtk, ABC_TYPE_STRASH, ABC_FUNC_AIG );
Abc_NtkBalancePerform( pNtk, pNtkAig, fDuplicate );
Abc_NtkFinalize( pNtk, pNtkAig );
// make sure everything is okay
if ( fCheck && !Abc_NtkCheck( pNtkAig ) )
{
printf( "Abc_NtkBalance: The network check has failed.\n" );
Abc_NtkDelete( pNtkAig );
return NULL;
}
return pNtkAig;
}
/**Function*************************************************************
Synopsis [Balances the AIG network.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkBalancePerform( Abc_Ntk_t * pNtk, Abc_Ntk_t * pNtkAig, bool fDuplicate )
{
int fCheck = 1;
ProgressBar * pProgress;
Abc_Obj_t * pNode, * pDriver;
int i;
// copy the constant node
Abc_AigConst1(pNtk->pManFunc)->pCopy = Abc_AigConst1(pNtkAig->pManFunc);
// set the level of PIs of AIG according to the arrival times of the old network
Abc_NtkSetNodeLevelsArrival( pNtk );
// perform balancing of POs
pProgress = Extra_ProgressBarStart( stdout, Abc_NtkCoNum(pNtk) );
Abc_NtkForEachCo( pNtk, pNode, i )
{
Extra_ProgressBarUpdate( pProgress, i, NULL );
// strash the driver node
pDriver = Abc_ObjFanin0(pNode);
Abc_NodeBalance_rec( pNtkAig, pDriver, fDuplicate );
}
Extra_ProgressBarStop( pProgress );
}
/**Function*************************************************************
Synopsis [Rebalances the multi-input node rooted at pNodeOld.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NodeBalance_rec( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pNodeOld, bool fDuplicate )
{
Abc_Aig_t * pMan = pNtkNew->pManFunc;
Abc_Obj_t * pNodeNew, * pNode1, * pNode2;
Vec_Ptr_t * vSuper;
int i;
assert( !Abc_ObjIsComplement(pNodeOld) );
// return if the result if known
if ( pNodeOld->pCopy )
return pNodeOld->pCopy;
assert( Abc_ObjIsNode(pNodeOld) );
// get the implication supergate
vSuper = Abc_NodeBalanceCone( pNodeOld, fDuplicate );
if ( vSuper->nSize == 0 )
{ // it means that the supergate contains two nodes in the opposite polarity
Vec_PtrFree( vSuper );
pNodeOld->pCopy = Abc_ObjNot(Abc_AigConst1(pMan));
return pNodeOld->pCopy;
}
// for each old node, derive the new well-balanced node
for ( i = 0; i < vSuper->nSize; i++ )
{
pNodeNew = Abc_NodeBalance_rec( pNtkNew, Abc_ObjRegular(vSuper->pArray[i]), fDuplicate );
vSuper->pArray[i] = Abc_ObjNotCond( pNodeNew, Abc_ObjIsComplement(vSuper->pArray[i]) );
}
// sort the new nodes by level in the decreasing order
Vec_PtrSort( vSuper, Abc_NodeCompareLevelsDecrease );
// balance the nodes
assert( vSuper->nSize > 1 );
while ( vSuper->nSize > 1 )
{
pNode1 = Vec_PtrPop(vSuper);
pNode2 = Vec_PtrPop(vSuper);
Abc_VecObjPushUniqueOrderByLevel( vSuper, Abc_AigAnd(pMan, pNode1, pNode2) );
}
// make sure the balanced node is not assigned
assert( pNodeOld->pCopy == NULL );
// mark the old node with the new node
pNodeOld->pCopy = vSuper->pArray[0];
Vec_PtrFree( vSuper );
return pNodeOld->pCopy;
}
/**Function*************************************************************
Synopsis [Collects the nodes in the cone delimited by fMarkA==1.]
Description [Returns -1 if the AND-cone has the same node in both polarities.
Returns 1 if the AND-cone has the same node in the same polarity. Returns 0
if the AND-cone has no repeated nodes.]
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Ptr_t * Abc_NodeBalanceCone( Abc_Obj_t * pNode, int fDuplicate )
{
Vec_Ptr_t * vNodes;
int RetValue, i;
assert( !Abc_ObjIsComplement(pNode) );
vNodes = Vec_PtrAlloc( 4 );
RetValue = Abc_NodeBalanceCone_rec( pNode, vNodes, 1, fDuplicate );
assert( vNodes->nSize > 0 );
for ( i = 0; i < vNodes->nSize; i++ )
Abc_ObjRegular((Abc_Obj_t *)vNodes->pArray[i])->fMarkB = 0;
if ( RetValue == -1 )
vNodes->nSize = 0;
return vNodes;
}
/**Function*************************************************************
Synopsis [Collects the nodes in the cone delimited by fMarkA==1.]
Description [Returns -1 if the AND-cone has the same node in both polarities.
Returns 1 if the AND-cone has the same node in the same polarity. Returns 0
if the AND-cone has no repeated nodes.]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NodeBalanceCone_rec( Abc_Obj_t * pNode, Vec_Ptr_t * vSuper, bool fFirst, bool fDuplicate )
{
int RetValue1, RetValue2, i;
// check if the node is visited
if ( Abc_ObjRegular(pNode)->fMarkB )
{
// check if the node occurs in the same polarity
for ( i = 0; i < vSuper->nSize; i++ )
if ( vSuper->pArray[i] == pNode )
return 1;
// check if the node is present in the opposite polarity
for ( i = 0; i < vSuper->nSize; i++ )
if ( vSuper->pArray[i] == Abc_ObjNot(pNode) )
return -1;
assert( 0 );
return 0;
}
// if the new node is complemented or a PI, another gate begins
if ( !fFirst && (Abc_ObjIsComplement(pNode) || !Abc_ObjIsNode(pNode) || !fDuplicate && (Abc_ObjFanoutNum(pNode) > 1)) )
{
Vec_PtrPush( vSuper, pNode );
Abc_ObjRegular(pNode)->fMarkB = 1;
return 0;
}
assert( !Abc_ObjIsComplement(pNode) );
assert( Abc_ObjIsNode(pNode) );
// go through the branches
RetValue1 = Abc_NodeBalanceCone_rec( Abc_ObjChild0(pNode), vSuper, 0, fDuplicate );
RetValue2 = Abc_NodeBalanceCone_rec( Abc_ObjChild1(pNode), vSuper, 0, fDuplicate );
if ( RetValue1 == -1 || RetValue2 == -1 )
return -1;
// return 1 if at least one branch has a duplicate
return RetValue1 || RetValue2;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
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