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/**CFile****************************************************************
FileName [sclBuff.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Standard-cell library representation.]
Synopsis [Buffering algorithms.]
Author [Alan Mishchenko, Niklas Een]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - August 24, 2012.]
Revision [$Id: sclBuff.c,v 1.0 2012/08/24 00:00:00 alanmi Exp $]
***********************************************************************/
#include "sclInt.h"
#include "map/mio/mio.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Make sure the network is in topo order without dangling nodes.]
Description [Returns 1 iff the network is fine.]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_SclCheckNtk( Abc_Ntk_t * p, int fVerbose )
{
Abc_Obj_t * pObj, * pFanin;
int i, k, fFlag = 1;
Abc_NtkIncrementTravId( p );
Abc_NtkForEachCi( p, pObj, i )
Abc_NodeSetTravIdCurrent( pObj );
Abc_NtkForEachNode( p, pObj, i )
{
Abc_ObjForEachFanin( pObj, pFanin, k )
if ( !Abc_NodeIsTravIdCurrent( pFanin ) )
printf( "obj %d and its fanin %d are not in the topo order\n", Abc_ObjId(pObj), Abc_ObjId(pFanin) ), fFlag = 0;
Abc_NodeSetTravIdCurrent( pObj );
if ( Abc_ObjFanoutNum(pObj) == 0 )
printf( "node %d has no fanout\n", Abc_ObjId(pObj) ), fFlag = 0;
if ( !fFlag )
break;
}
if ( fFlag && fVerbose )
printf( "The network is in topo order and no dangling nodes.\n" );
return fFlag;
}
/**Function*************************************************************
Synopsis []
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_SclCheckNtk2( Abc_Ntk_t * p )
{
Abc_Obj_t * pObj, * pFanout;
int i, k;
Abc_NtkStartReverseLevels( p, 0 );
Abc_NtkForEachNode( p, pObj, i )
{
if ( Abc_ObjFanoutNum(pObj) <= 3 )
continue;
printf( "Node %5d (%2d) : fans = %3d ", i, Abc_ObjLevel(pObj), Abc_ObjFanoutNum(pObj) );
Abc_ObjForEachFanout( pObj, pFanout, k )
printf( "%d ", Abc_ObjReverseLevel(pFanout) );
printf( "\n" );
}
return 1;
}
/**Function*************************************************************
Synopsis [Performs buffering of the mapped network.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NodeCompareLevels( Abc_Obj_t ** pp1, Abc_Obj_t ** pp2 )
{
int Diff = Abc_ObjLevel(*pp1) - Abc_ObjLevel(*pp2);
if ( Diff < 0 )
return -1;
if ( Diff > 0 )
return 1;
Diff = (*pp1)->Id - (*pp2)->Id; // needed to make qsort() platform-infependent
if ( Diff < 0 )
return -1;
if ( Diff > 0 )
return 1;
return 0;
}
int Abc_SclComputeReverseLevel( Abc_Obj_t * pObj )
{
Abc_Obj_t * pFanout;
int i, Level = 0;
Abc_ObjForEachFanout( pObj, pFanout, i )
Level = Abc_MaxInt( Level, pFanout->Level );
return Level + 1;
}
Abc_Obj_t * Abc_SclPerformBufferingOne( Abc_Obj_t * pObj, int Degree, int fVerbose )
{
Vec_Ptr_t * vFanouts;
Abc_Obj_t * pBuffer, * pFanout;
int i, Degree0 = Degree;
assert( Abc_ObjFanoutNum(pObj) > Degree );
// collect fanouts and sort by reverse level
vFanouts = Vec_PtrAlloc( Abc_ObjFanoutNum(pObj) );
Abc_NodeCollectFanouts( pObj, vFanouts );
Vec_PtrSort( vFanouts, (int (*)(void))Abc_NodeCompareLevels );
// select the first Degree fanouts
pBuffer = Abc_NtkCreateNodeBuf( pObj->pNtk, NULL );
// check if it is possible to not increase level
if ( Vec_PtrSize(vFanouts) < 2 * Degree )
{
Abc_Obj_t * pFanPrev = (Abc_Obj_t *)Vec_PtrEntry(vFanouts, Vec_PtrSize(vFanouts)-1-Degree);
Abc_Obj_t * pFanThis = (Abc_Obj_t *)Vec_PtrEntry(vFanouts, Degree-1);
Abc_Obj_t * pFanLast = (Abc_Obj_t *)Vec_PtrEntryLast(vFanouts);
if ( Abc_ObjLevel(pFanThis) == Abc_ObjLevel(pFanLast) &&
Abc_ObjLevel(pFanPrev) < Abc_ObjLevel(pFanThis) )
{
// find the first one whose level is the same as last
Vec_PtrForEachEntry( Abc_Obj_t *, vFanouts, pFanout, i )
if ( Abc_ObjLevel(pFanout) == Abc_ObjLevel(pFanLast) )
break;
assert( i < Vec_PtrSize(vFanouts) );
if ( i > 1 )
Degree = i;
}
// make the last two more well-balanced
if ( Degree == Degree0 && Degree > Vec_PtrSize(vFanouts) - Degree )
Degree = Vec_PtrSize(vFanouts)/2 + (Vec_PtrSize(vFanouts) & 1);
assert( Degree <= Degree0 );
}
// select fanouts
Vec_PtrForEachEntryStop( Abc_Obj_t *, vFanouts, pFanout, i, Degree )
Abc_ObjPatchFanin( pFanout, pObj, pBuffer );
if ( fVerbose )
{
printf( "%5d : ", Abc_ObjId(pObj) );
Vec_PtrForEachEntry( Abc_Obj_t *, vFanouts, pFanout, i )
printf( "%d%s ", Abc_ObjLevel(pFanout), i == Degree-1 ? " " : "" );
printf( "\n" );
}
Vec_PtrFree( vFanouts );
Abc_ObjAddFanin( pBuffer, pObj );
pBuffer->Level = Abc_SclComputeReverseLevel( pBuffer );
return pBuffer;
}
void Abc_SclPerformBuffering_rec( Abc_Obj_t * pObj, int Degree, int fVerbose )
{
Abc_Obj_t * pFanout;
int i;
if ( Abc_NodeIsTravIdCurrent( pObj ) )
return;
Abc_NodeSetTravIdCurrent( pObj );
pObj->Level = 0;
if ( Abc_ObjIsCo(pObj) )
return;
assert( Abc_ObjIsCi(pObj) || Abc_ObjIsNode(pObj) );
// buffer fanouts and collect reverse levels
Abc_ObjForEachFanout( pObj, pFanout, i )
Abc_SclPerformBuffering_rec( pFanout, Degree, fVerbose );
// perform buffering as long as needed
while ( Abc_ObjFanoutNum(pObj) > Degree )
Abc_SclPerformBufferingOne( pObj, Degree, fVerbose );
// compute the new level of the node
pObj->Level = Abc_SclComputeReverseLevel( pObj );
}
Abc_Ntk_t * Abc_SclPerformBuffering( Abc_Ntk_t * p, int Degree, int fVerbose )
{
Vec_Int_t * vCiLevs;
Abc_Ntk_t * pNew;
Abc_Obj_t * pObj;
int i;
assert( Abc_NtkHasMapping(p) );
// remember CI levels
vCiLevs = Vec_IntAlloc( Abc_NtkCiNum(p) );
Abc_NtkForEachCi( p, pObj, i )
Vec_IntPush( vCiLevs, Abc_ObjLevel(pObj) );
// perform buffering
Abc_NtkIncrementTravId( p );
Abc_NtkForEachCi( p, pObj, i )
Abc_SclPerformBuffering_rec( pObj, Degree, fVerbose );
// recompute logic levels
Abc_NtkForEachCi( p, pObj, i )
pObj->Level = Vec_IntEntry( vCiLevs, i );
Abc_NtkForEachNode( p, pObj, i )
Abc_ObjLevelNew( pObj );
Vec_IntFree( vCiLevs );
// duplication in topo order
pNew = Abc_NtkDupDfs( p );
Abc_SclCheckNtk( pNew, fVerbose );
// Abc_NtkDelete( pNew );
return pNew;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
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