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/**CFile****************************************************************
FileName [rwrCut.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [DAG-aware AIG rewriting package.]
Synopsis [Cut computation.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: rwrCut.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "rwr.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
static Rwr_Cut_t * Rwr_CutAlloc( Abc_ManRwr_t * p );
static Rwr_Cut_t * Rwr_CutCreateTriv( Abc_ManRwr_t * p, Abc_Obj_t * pNode );
static Rwr_Cut_t * Rwr_CutsMerge( Abc_ManRwr_t * p, Rwr_Cut_t * pCut0, Rwr_Cut_t * pCut1, int fCompl0, int fCompl1 );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Assigns elementary cuts to the PIs.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkManRwrStartCuts( Abc_ManRwr_t * p, Abc_Ntk_t * pNtk )
{
Abc_Obj_t * pNode;
int i;
// set the trivial cuts
Abc_NtkCleanCopy( pNtk );
Abc_NtkForEachCi( pNtk, pNode, i )
pNode->pCopy = (Abc_Obj_t *)Rwr_CutCreateTriv( p, pNode );
// precompute the required times for all internal nodes
p->vFanNums = Rwt_NtkFanoutCounters( pNtk );
// save the fanout counters for all internal nodes
p->vReqTimes = Rwt_NtkRequiredLevels( pNtk );
}
/**Function*************************************************************
Synopsis [Computes cuts for one node.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NodeRwrComputeCuts( Abc_ManRwr_t * p, Abc_Obj_t * pNode )
{
Rwr_Cut_t * pCuts0, * pCuts1, * pTemp0, * pTemp1, * pCut;
Rwr_Cut_t * pList = NULL, ** ppPlace = &pList; // linked list of cuts
assert( Abc_ObjIsNode(pNode) );
if ( Abc_NodeIsConst(pNode) )
return;
// create the elementary cut
pCut = Rwr_CutCreateTriv( p, pNode );
// add it to the linked list
*ppPlace = pCut; ppPlace = &pCut->pNext;
// create cuts by merging pairwise
pCuts0 = (Rwr_Cut_t *)Abc_ObjFanin0(pNode)->pCopy;
pCuts1 = (Rwr_Cut_t *)Abc_ObjFanin1(pNode)->pCopy;
assert( pCuts0 && pCuts1 );
for ( pTemp0 = pCuts0; pTemp0; pTemp0 = pTemp0->pNext )
for ( pTemp1 = pCuts1; pTemp1; pTemp1 = pTemp1->pNext )
{
pCut = Rwr_CutsMerge( p, pTemp0, pTemp1, Abc_ObjFaninC0(pNode), Abc_ObjFaninC1(pNode) );
if ( pCut == NULL )
continue;
// add it to the linked list
*ppPlace = pCut; ppPlace = &pCut->pNext;
}
// set the linked list
pNode->pCopy = (Abc_Obj_t *)pList;
}
/**Function*************************************************************
Synopsis [Start the cut computation.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Rwr_Cut_t * Rwr_CutsMerge( Abc_ManRwr_t * p, Rwr_Cut_t * pCut0, Rwr_Cut_t * pCut1, int fCompl0, int fCompl1 )
{
Abc_Obj_t * ppNodes[4], * pNodeTemp;
Rwr_Cut_t * pCut;
unsigned uPhase, uTruth0, uTruth1;
int i, k, min, nTotal;
// solve the most typical case: both cuts are four input
if ( pCut0->nLeaves == 4 && pCut1->nLeaves == 4 )
{
for ( i = 0; i < 4; i++ )
if ( pCut0->ppLeaves[i] != pCut1->ppLeaves[i] )
return NULL;
// create the cut
pCut = Rwr_CutAlloc( p );
pCut->nLeaves = 4;
for ( i = 0; i < 4; i++ )
pCut->ppLeaves[i] = pCut0->ppLeaves[i];
pCut->uTruth = (fCompl0? ~pCut0->uTruth : pCut0->uTruth) & (fCompl1? ~pCut1->uTruth : pCut1->uTruth) & 0xFFFF;
return pCut;
}
// create the set of new nodes
// count the number of unique entries in pCut1
nTotal = pCut0->nLeaves;
for ( i = 0; i < (int)pCut1->nLeaves; i++ )
{
// try to find this entry among the leaves of pCut0
for ( k = 0; k < (int)pCut0->nLeaves; k++ )
if ( pCut1->ppLeaves[i] == pCut0->ppLeaves[k] )
break;
if ( k < (int)pCut0->nLeaves ) // found
continue;
// we found a new entry to add
if ( nTotal == 4 )
return NULL;
ppNodes[nTotal++] = pCut1->ppLeaves[i];
}
// we know that the feasible cut exists
// add the starting entries
for ( k = 0; k < (int)pCut0->nLeaves; k++ )
ppNodes[k] = pCut0->ppLeaves[k];
// selection-sort the entries
for ( i = 0; i < nTotal - 1; i++ )
{
min = i;
for ( k = i+1; k < nTotal; k++ )
if ( ppNodes[k]->Id < ppNodes[min]->Id )
min = k;
pNodeTemp = ppNodes[i];
ppNodes[i] = ppNodes[min];
ppNodes[min] = pNodeTemp;
}
// find the mapping from the old nodes to the new
if ( pCut0->nLeaves == 4 )
uTruth0 = pCut0->uTruth;
else
{
uPhase = 0;
for ( i = 0; i < (int)pCut0->nLeaves; i++ )
{
for ( k = 0; k < nTotal; k++ )
if ( pCut0->ppLeaves[i] == ppNodes[k] )
break;
uPhase |= (1 << k);
}
assert( uPhase < 16 );
assert( pCut0->uTruth < 256 );
uTruth0 = p->puPerms[pCut0->uTruth][uPhase];
}
// find the mapping from the old nodes to the new
if ( pCut1->nLeaves == 4 )
uTruth1 = pCut1->uTruth;
else
{
uPhase = 0;
for ( i = 0; i < (int)pCut1->nLeaves; i++ )
{
for ( k = 0; k < nTotal; k++ )
if ( pCut1->ppLeaves[i] == ppNodes[k] )
break;
uPhase |= (1 << k);
}
assert( uPhase < 16 );
assert( pCut1->uTruth < 256 );
uTruth1 = p->puPerms[pCut1->uTruth][uPhase];
}
// create the cut
pCut = Rwr_CutAlloc( p );
pCut->nLeaves = nTotal;
for ( i = 0; i < nTotal; i++ )
pCut->ppLeaves[i] = ppNodes[i];
pCut->uTruth = (fCompl0? ~uTruth0 : uTruth0) & (fCompl1? ~uTruth1 : uTruth1) & 0xFFFF;
return pCut;
}
/**Function*************************************************************
Synopsis [Start the cut computation.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Rwr_Cut_t * Rwr_CutAlloc( Abc_ManRwr_t * p )
{
Rwr_Cut_t * pCut;
pCut = (Rwr_Cut_t *)Extra_MmFixedEntryFetch( p->pMmNode );
memset( pCut, 0, sizeof(Rwr_Cut_t) );
return pCut;
}
/**Function*************************************************************
Synopsis [Start the cut computation.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Rwr_Cut_t * Rwr_CutCreateTriv( Abc_ManRwr_t * p, Abc_Obj_t * pNode )
{
Rwr_Cut_t * pCut;
pCut = Rwr_CutAlloc( p );
pCut->nLeaves = 1;
pCut->ppLeaves[0] = pNode;
pCut->uTruth = 0xAAAA;
return pCut;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
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