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/**CFile****************************************************************
FileName [giaShrink.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Scalable AIG package.]
Synopsis [Implementation of mapShrink based on ideas of Niklas Een.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: giaShrink.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "gia.h"
#include "aig/aig/aig.h"
#include "opt/dar/dar.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
extern int Dar_LibEvalBuild( Gia_Man_t * p, Vec_Int_t * vCut, unsigned uTruth, int fKeepLevel, Vec_Int_t * vLeavesBest );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Performs AIG shrinking using the current mapping.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Gia_Man_t * Gia_ManPerformMapShrink( Gia_Man_t * p, int fKeepLevel, int fVerbose )
{
Vec_Int_t * vLeaves, * vTruth, * vVisited, * vLeavesBest;
Gia_Man_t * pNew, * pTemp;
Gia_Obj_t * pObj, * pFanin;
unsigned * pTruth;
int i, k, iFan;
clock_t clk = clock();
// int ClassCounts[222] = {0};
int * pLutClass, Counter = 0;
assert( p->pMapping != NULL );
if ( Gia_ManLutSizeMax( p ) > 4 )
{
printf( "Resynthesis is not performed when nodes have more than 4 inputs.\n" );
return NULL;
}
pLutClass = ABC_CALLOC( int, Gia_ManObjNum(p) );
vLeaves = Vec_IntAlloc( 0 );
vTruth = Vec_IntAlloc( (1<<16) );
vVisited = Vec_IntAlloc( 0 );
vLeavesBest = Vec_IntAlloc( 4 );
// prepare the library
Dar_LibPrepare( 5 );
// clean the old manager
Gia_ManCleanTruth( p );
Gia_ManSetPhase( p );
Gia_ManFillValue( p );
Gia_ManConst0(p)->Value = 0;
// start the new manager
pNew = Gia_ManStart( Gia_ManObjNum(p) );
pNew->pName = Abc_UtilStrsav( p->pName );
Gia_ManHashAlloc( pNew );
Gia_ManCleanLevels( pNew, Gia_ManObjNum(p) );
Gia_ManForEachObj1( p, pObj, i )
{
if ( Gia_ObjIsCi(pObj) )
{
pObj->Value = Gia_ManAppendCi( pNew );
Gia_ObjSetLevel( pNew, Gia_ObjFromLit(pNew, Gia_ObjValue(pObj)), Gia_ObjLevel(p, pObj) );
}
else if ( Gia_ObjIsCo(pObj) )
{
pObj->Value = Gia_ManAppendCo( pNew, Gia_ObjFanin0Copy(pObj) );
}
else if ( Gia_ObjIsLut(p, i) )
{
Counter++;
// collect leaves of this gate
Vec_IntClear( vLeaves );
Gia_LutForEachFanin( p, i, iFan, k )
Vec_IntPush( vLeaves, iFan );
for ( ; k < 4; k++ )
Vec_IntPush( vLeaves, 0 );
//.compute the truth table
pTruth = Gia_ManConvertAigToTruth( p, pObj, vLeaves, vTruth, vVisited );
// change from node IDs to their literals
Gia_ManForEachObjVec( vLeaves, p, pFanin, k )
{
assert( Gia_ObjValue(pFanin) != ~0 );
Vec_IntWriteEntry( vLeaves, k, Gia_ObjValue(pFanin) );
}
// derive new structre
if ( Gia_ManTruthIsConst0(pTruth, Vec_IntSize(vLeaves)) )
pObj->Value = 0;
else if ( Gia_ManTruthIsConst1(pTruth, Vec_IntSize(vLeaves)) )
pObj->Value = 1;
else
{
pObj->Value = Dar_LibEvalBuild( pNew, vLeaves, 0xffff & *pTruth, fKeepLevel, vLeavesBest );
pObj->Value = Abc_LitNotCond( pObj->Value, Gia_ObjPhaseRealLit(pNew, pObj->Value) ^ pObj->fPhase );
}
}
}
// cleanup the AIG
Gia_ManHashStop( pNew );
// check the presence of dangling nodes
if ( Gia_ManHasDangling(pNew) )
{
pNew = Gia_ManCleanup( pTemp = pNew );
if ( Gia_ManAndNum(pNew) != Gia_ManAndNum(pTemp) )
printf( "Gia_ManPerformMapShrink() node reduction after sweep %6d -> %6d.\n", Gia_ManAndNum(pTemp), Gia_ManAndNum(pNew) );
Gia_ManStop( pTemp );
}
Gia_ManSetRegNum( pNew, Gia_ManRegNum(p) );
Vec_IntFree( vLeaves );
Vec_IntFree( vTruth );
Vec_IntFree( vVisited );
Vec_IntFree( vLeavesBest );
if ( fVerbose )
{
printf( "Total gain in AIG nodes = %d. ", Gia_ManObjNum(p)-Gia_ManObjNum(pNew) );
ABC_PRT( "Total runtime", clock() - clk );
}
ABC_FREE( pLutClass );
return pNew;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
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