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/**CFile****************************************************************
FileName [mfsDiv.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [The good old minimization with complete don't-cares.]
Synopsis [Procedures to compute candidate divisors.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: mfsDiv.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "mfsInt.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Marks and collects the TFI cone of the node.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_MfsWinMarkTfi_rec( Abc_Obj_t * pObj, Vec_Ptr_t * vCone )
{
Abc_Obj_t * pFanin;
int i;
if ( Abc_NodeIsTravIdCurrent(pObj) )
return;
Abc_NodeSetTravIdCurrent( pObj );
if ( Abc_ObjIsCi(pObj) )
{
Vec_PtrPush( vCone, pObj );
return;
}
assert( Abc_ObjIsNode(pObj) );
// visit the fanins of the node
Abc_ObjForEachFanin( pObj, pFanin, i )
Abc_MfsWinMarkTfi_rec( pFanin, vCone );
Vec_PtrPush( vCone, pObj );
}
/**Function*************************************************************
Synopsis [Marks and collects the TFI cone of the node.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Ptr_t * Abc_MfsWinMarkTfi( Abc_Obj_t * pNode )
{
Vec_Ptr_t * vCone;
vCone = Vec_PtrAlloc( 100 );
Abc_MfsWinMarkTfi_rec( pNode, vCone );
return vCone;
}
/**Function*************************************************************
Synopsis [Marks the TFO of the collected nodes up to the given level.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_MfsWinSweepLeafTfo_rec( Abc_Obj_t * pObj, int nLevelLimit )
{
Abc_Obj_t * pFanout;
int i;
if ( Abc_ObjIsCo(pObj) || (int)pObj->Level > nLevelLimit )
return;
if ( Abc_NodeIsTravIdCurrent(pObj) )
return;
Abc_NodeSetTravIdCurrent( pObj );
Abc_ObjForEachFanout( pObj, pFanout, i )
Abc_MfsWinSweepLeafTfo_rec( pFanout, nLevelLimit );
}
/**Function*************************************************************
Synopsis [Dereferences the node's MFFC.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_MfsNodeDeref_rec( Abc_Obj_t * pNode )
{
Abc_Obj_t * pFanin;
int i, Counter = 1;
if ( Abc_ObjIsCi(pNode) )
return 0;
Abc_NodeSetTravIdCurrent( pNode );
Abc_ObjForEachFanin( pNode, pFanin, i )
{
assert( pFanin->vFanouts.nSize > 0 );
if ( --pFanin->vFanouts.nSize == 0 )
Counter += Abc_MfsNodeDeref_rec( pFanin );
}
return Counter;
}
/**Function*************************************************************
Synopsis [References the node's MFFC.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_MfsNodeRef_rec( Abc_Obj_t * pNode )
{
Abc_Obj_t * pFanin;
int i, Counter = 1;
if ( Abc_ObjIsCi(pNode) )
return 0;
Abc_ObjForEachFanin( pNode, pFanin, i )
{
if ( pFanin->vFanouts.nSize++ == 0 )
Counter += Abc_MfsNodeRef_rec( pFanin );
}
return Counter;
}
/**Function*************************************************************
Synopsis [Labels MFFC of the node with the current trav ID.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_MfsWinVisitMffc( Abc_Obj_t * pNode )
{
int Count1, Count2;
assert( Abc_ObjIsNode(pNode) );
// dereference the node (mark with the current trav ID)
Count1 = Abc_MfsNodeDeref_rec( pNode );
// reference it back
Count2 = Abc_MfsNodeRef_rec( pNode );
assert( Count1 == Count2 );
return Count1;
}
/**Function*************************************************************
Synopsis [Computes divisors and add them to nodes in the window.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Ptr_t * Abc_MfsComputeDivisors( Mfs_Man_t * p, Abc_Obj_t * pNode, int nLevDivMax )
{
Vec_Ptr_t * vCone, * vDivs;
Abc_Obj_t * pObj, * pFanout, * pFanin;
int k, f, m;
int nDivsPlus = 0, nTrueSupp;
assert( p->vDivs == NULL );
// mark the TFI with the current trav ID
Abc_NtkIncrementTravId( pNode->pNtk );
vCone = Abc_MfsWinMarkTfi( pNode );
// count the number of PIs
nTrueSupp = 0;
Vec_PtrForEachEntry( Abc_Obj_t *, vCone, pObj, k )
nTrueSupp += Abc_ObjIsCi(pObj);
// printf( "%d(%d) ", Vec_PtrSize(p->vSupp), m );
// mark with the current trav ID those nodes that should not be divisors:
// (1) the node and its TFO
// (2) the MFFC of the node
// (3) the node's fanins (these are treated as a special case)
Abc_NtkIncrementTravId( pNode->pNtk );
Abc_MfsWinSweepLeafTfo_rec( pNode, nLevDivMax );
Abc_MfsWinVisitMffc( pNode );
Abc_ObjForEachFanin( pNode, pObj, k )
Abc_NodeSetTravIdCurrent( pObj );
// at this point the nodes are marked with two trav IDs:
// nodes to be collected as divisors are marked with previous trav ID
// nodes to be avoided as divisors are marked with current trav ID
// start collecting the divisors
vDivs = Vec_PtrAlloc( p->pPars->nDivMax );
Vec_PtrForEachEntry( Abc_Obj_t *, vCone, pObj, k )
{
if ( !Abc_NodeIsTravIdPrevious(pObj) )
continue;
if ( (int)pObj->Level > nLevDivMax )
continue;
Vec_PtrPush( vDivs, pObj );
if ( Vec_PtrSize(vDivs) >= p->pPars->nDivMax )
break;
}
Vec_PtrFree( vCone );
// explore the fanouts of already collected divisors
if ( Vec_PtrSize(vDivs) < p->pPars->nDivMax )
Vec_PtrForEachEntry( Abc_Obj_t *, vDivs, pObj, k )
{
// consider fanouts of this node
Abc_ObjForEachFanout( pObj, pFanout, f )
{
// stop if there are too many fanouts
if ( f > 20 )
break;
// skip nodes that are already added
if ( Abc_NodeIsTravIdPrevious(pFanout) )
continue;
// skip nodes in the TFO or in the MFFC of node
if ( Abc_NodeIsTravIdCurrent(pFanout) )
continue;
// skip COs
if ( !Abc_ObjIsNode(pFanout) )
continue;
// skip nodes with large level
if ( (int)pFanout->Level > nLevDivMax )
continue;
// skip nodes whose fanins are not divisors -- here we skip more than we need to skip!!! (revise later) August 7, 2009
Abc_ObjForEachFanin( pFanout, pFanin, m )
if ( !Abc_NodeIsTravIdPrevious(pFanin) )
break;
if ( m < Abc_ObjFaninNum(pFanout) )
continue;
// make sure this divisor in not among the nodes
// Vec_PtrForEachEntry( Abc_Obj_t *, p->vNodes, pFanin, m )
// assert( pFanout != pFanin );
// add the node to the divisors
Vec_PtrPush( vDivs, pFanout );
// Vec_PtrPush( p->vNodes, pFanout );
Vec_PtrPushUnique( p->vNodes, pFanout );
Abc_NodeSetTravIdPrevious( pFanout );
nDivsPlus++;
if ( Vec_PtrSize(vDivs) >= p->pPars->nDivMax )
break;
}
if ( Vec_PtrSize(vDivs) >= p->pPars->nDivMax )
break;
}
// sort the divisors by level in the increasing order
Vec_PtrSort( vDivs, (int (*)(void))Abc_NodeCompareLevelsIncrease );
// add the fanins of the node
Abc_ObjForEachFanin( pNode, pFanin, k )
Vec_PtrPush( vDivs, pFanin );
/*
printf( "Node level = %d. ", Abc_ObjLevel(p->pNode) );
Vec_PtrForEachEntryStart( Abc_Obj_t *, vDivs, pObj, k, Vec_PtrSize(vDivs)-p->nDivsPlus )
printf( "%d ", Abc_ObjLevel(pObj) );
printf( "\n" );
*/
//printf( "%d ", p->nDivsPlus );
// printf( "(%d+%d)(%d+%d+%d) ", Vec_PtrSize(p->vSupp), Vec_PtrSize(p->vNodes),
// nTrueSupp, Vec_PtrSize(vDivs)-nTrueSupp-nDivsPlus, nDivsPlus );
return vDivs;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
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