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/**CFile****************************************************************
FileName [abcRes.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Network and node package.]
Synopsis [Reconvergence=driven cut computation.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: abcRes.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "abc.h"
#include "ft.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
struct Abc_ManCut_t_
{
// user specified parameters
int nNodeSizeMax; // the limit on the size of the supernode
int nConeSizeMax; // the limit on the size of the containing cone
// internal parameters
Vec_Ptr_t * vFaninsNode; // fanins of the supernode
Vec_Ptr_t * vInsideNode; // inside of the supernode
Vec_Ptr_t * vFaninsCone; // fanins of the containing cone
Vec_Ptr_t * vInsideCone; // inside of the containing cone
Vec_Ptr_t * vVisited; // the visited nodes
};
static int Abc_NodeFindCut_int( Vec_Ptr_t * vInside, Vec_Ptr_t * vFanins, int nSizeLimit );
static int Abc_NodeGetFaninCost( Abc_Obj_t * pNode );
static void Abc_NodeConeMarkCollect_rec( Abc_Obj_t * pNode, Vec_Ptr_t * vVisited );
static void Abc_NodeConeMark( Vec_Ptr_t * vVisited );
static void Abc_NodeConeUnmark( Vec_Ptr_t * vVisited );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Finds a reconvergence-driven cut.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Ptr_t * Abc_NodeFindCut( Abc_ManCut_t * p, Abc_Obj_t * pRoot )
{
Abc_Obj_t * pNode;
int i;
// mark TFI using fMarkA
Vec_PtrClear( p->vVisited );
Abc_NodeConeMarkCollect_rec( pRoot, p->vVisited );
// start the reconvergence-driven node
Vec_PtrClear( p->vInsideNode );
Vec_PtrClear( p->vFaninsNode );
Vec_PtrPush( p->vFaninsNode, pRoot );
pRoot->fMarkB = 1;
// compute reconvergence-driven node
while ( Abc_NodeFindCut_int( p->vInsideNode, p->vFaninsNode, p->nNodeSizeMax ) );
// compute reconvergence-driven cone
Vec_PtrClear( p->vInsideCone );
Vec_PtrClear( p->vFaninsCone );
if ( p->nConeSizeMax > p->nNodeSizeMax )
{
// copy the node into the cone
Vec_PtrForEachEntry( p->vInsideNode, pNode, i )
Vec_PtrPush( p->vInsideCone, pNode );
Vec_PtrForEachEntry( p->vFaninsNode, pNode, i )
Vec_PtrPush( p->vFaninsCone, pNode );
// compute reconvergence-driven cone
while ( Abc_NodeFindCut_int( p->vInsideCone, p->vFaninsCone, p->nConeSizeMax ) );
// unmark the nodes of the sets
Vec_PtrForEachEntry( p->vInsideCone, pNode, i )
pNode->fMarkB = 0;
Vec_PtrForEachEntry( p->vFaninsCone, pNode, i )
pNode->fMarkB = 0;
}
else
{
// unmark the nodes of the sets
Vec_PtrForEachEntry( p->vInsideNode, pNode, i )
pNode->fMarkB = 0;
Vec_PtrForEachEntry( p->vFaninsNode, pNode, i )
pNode->fMarkB = 0;
}
// unmark TFI using fMarkA
Abc_NodeConeUnmark( p->vVisited );
return p->vFaninsNode;
}
/**Function*************************************************************
Synopsis [Finds a reconvergence-driven cut.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NodeFindCut_int( Vec_Ptr_t * vInside, Vec_Ptr_t * vFanins, int nSizeLimit )
{
Abc_Obj_t * pNode, * pFaninBest, * pNext;
int CostBest, CostCur, i;
// find the best fanin
CostBest = 100;
pFaninBest = NULL;
Vec_PtrForEachEntry( vFanins, pNode, i )
{
CostCur = Abc_NodeGetFaninCost( pNode );
if ( CostBest > CostCur )
{
CostBest = CostCur;
pFaninBest = pNode;
}
}
if ( pFaninBest == NULL )
return 0;
assert( CostBest < 3 );
if ( vFanins->nSize - 1 + CostBest > nSizeLimit )
return 0;
assert( Abc_ObjIsNode(pFaninBest) );
// remove the node from the array
Vec_PtrRemove( vFanins, pFaninBest );
// add the node to the set
Vec_PtrPush( vInside, pFaninBest );
// add the left child to the fanins
pNext = Abc_ObjFanin0(pFaninBest);
if ( !pNext->fMarkB )
{
pNext->fMarkB = 1;
Vec_PtrPush( vFanins, pNext );
}
// add the right child to the fanins
pNext = Abc_ObjFanin1(pFaninBest);
if ( !pNext->fMarkB )
{
pNext->fMarkB = 1;
Vec_PtrPush( vFanins, pNext );
}
assert( vFanins->nSize <= nSizeLimit );
// keep doing this
return 1;
}
/**Function*************************************************************
Synopsis [Evaluate the fanin cost.]
Description [Returns the number of fanins that will be brought in.
Returns large number if the node cannot be added.]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NodeGetFaninCost( Abc_Obj_t * pNode )
{
Abc_Obj_t * pFanout;
int i;
assert( pNode->fMarkA == 1 ); // this node is in the TFI
assert( pNode->fMarkB == 1 ); // this node is in the constructed cone
// check the PI node
if ( !Abc_ObjIsNode(pNode) )
return 999;
// check the fanouts
Abc_ObjForEachFanout( pNode, pFanout, i )
if ( pFanout->fMarkA && pFanout->fMarkB == 0 ) // in the cone but not in the set
return 999;
// the fanouts are in the TFI and inside the constructed cone
// return the number of fanins that will be on the boundary if this node is added
return (!Abc_ObjFanin0(pNode)->fMarkB) + (!Abc_ObjFanin1(pNode)->fMarkB);
}
/**Function*************************************************************
Synopsis [Marks the TFI cone.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NodeConeMarkCollect_rec( Abc_Obj_t * pNode, Vec_Ptr_t * vVisited )
{
if ( pNode->fMarkA == 1 )
return;
// visit transitive fanin
if ( Abc_ObjIsNode(pNode) )
{
Abc_NodeConeMarkCollect_rec( Abc_ObjFanin0(pNode), vVisited );
Abc_NodeConeMarkCollect_rec( Abc_ObjFanin1(pNode), vVisited );
}
assert( pNode->fMarkA == 0 );
pNode->fMarkA = 1;
Vec_PtrPush( vVisited, pNode );
}
/**Function*************************************************************
Synopsis [Unmarks the TFI cone.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NodeConeMark( Vec_Ptr_t * vVisited )
{
int i;
for ( i = 0; i < vVisited->nSize; i++ )
((Abc_Obj_t *)vVisited->pArray)->fMarkA = 1;
}
/**Function*************************************************************
Synopsis [Unmarks the TFI cone.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NodeConeUnmark( Vec_Ptr_t * vVisited )
{
int i;
for ( i = 0; i < vVisited->nSize; i++ )
((Abc_Obj_t *)vVisited->pArray)->fMarkA = 0;
}
/**Function*************************************************************
Synopsis [Returns BDD representing the logic function of the cone.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
DdNode * Abc_NodeConeBdd( DdManager * dd, DdNode ** pbVars, Abc_Obj_t * pNode, Vec_Ptr_t * vFanins, Vec_Ptr_t * vVisited )
{
DdNode * bFunc0, * bFunc1, * bFunc;
int i;
// mark the fanins of the cone
Abc_NodeConeMark( vFanins );
// collect the nodes in the DFS order
Vec_PtrClear( vVisited );
Abc_NodeConeMarkCollect_rec( pNode, vVisited );
// unmark both sets
Abc_NodeConeUnmark( vFanins );
Abc_NodeConeUnmark( vVisited );
// set the elementary BDDs
Vec_PtrForEachEntry( vFanins, pNode, i )
pNode->pCopy = (Abc_Obj_t *)pbVars[i];
// compute the BDDs for the collected nodes
Vec_PtrForEachEntry( vVisited, pNode, i )
{
bFunc0 = Cudd_NotCond( Abc_ObjFanin0(pNode)->pCopy, Abc_ObjFaninC0(pNode) );
bFunc1 = Cudd_NotCond( Abc_ObjFanin1(pNode)->pCopy, Abc_ObjFaninC1(pNode) );
bFunc = Cudd_bddAnd( dd, bFunc0, bFunc1 ); Cudd_Ref( bFunc );
pNode->pCopy = (Abc_Obj_t *)bFunc;
}
Cudd_Ref( bFunc );
// dereference the intermediate ones
Vec_PtrForEachEntry( vVisited, pNode, i )
Cudd_RecursiveDeref( dd, (DdNode *)pNode->pCopy );
Cudd_Deref( bFunc );
return bFunc;
}
/**Function*************************************************************
Synopsis [Starts the resynthesis manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_ManCut_t * Abc_NtkManCutStart( int nNodeSizeMax, int nConeSizeMax )
{
Abc_ManCut_t * p;
p = ALLOC( Abc_ManCut_t, 1 );
memset( p, 0, sizeof(Abc_ManCut_t) );
p->vFaninsNode = Vec_PtrAlloc( 100 );
p->vInsideNode = Vec_PtrAlloc( 100 );
p->vFaninsCone = Vec_PtrAlloc( 100 );
p->vInsideCone = Vec_PtrAlloc( 100 );
p->vVisited = Vec_PtrAlloc( 100 );
p->nNodeSizeMax = nNodeSizeMax;
p->nConeSizeMax = nConeSizeMax;
return p;
}
/**Function*************************************************************
Synopsis [Stops the resynthesis manager.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkManCutStop( Abc_ManCut_t * p )
{
Vec_PtrFree( p->vFaninsNode );
Vec_PtrFree( p->vInsideNode );
Vec_PtrFree( p->vFaninsCone );
Vec_PtrFree( p->vInsideCone );
Vec_PtrFree( p->vVisited );
free( p );
}
/**Function*************************************************************
Synopsis [Collects the TFO of the cut in the topological order.]
Description [TFO of the cut is defined as a set of nodes, for which the cut
is a cut, that is, every path from the collected nodes to the CIs goes through
a node in the cut. The nodes are collected if their level does not exceed
the given number (LevelMax). The nodes are returned in the topological order.
If the root node is given, its MFFC is marked, so that the collected nodes
do not contain any nodes in the MFFC.]
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NodeCollectTfoCands( Abc_Ntk_t * pNtk, Abc_Obj_t * pRoot,
Vec_Ptr_t * vFanins, int LevelMax, Vec_Vec_t * vLevels, Vec_Ptr_t * vResult )
{
Vec_Ptr_t * vVec;
Abc_Obj_t * pNode, * pFanout;
int i, k, v, LevelMin;
assert( Abc_NtkIsAig(pNtk) );
// assuming that the structure is clean
Vec_VecForEachLevel( vLevels, vVec, i )
assert( vVec->nSize == 0 );
// put fanins into the structure while labeling them
Abc_NtkIncrementTravId( pNtk );
LevelMin = ABC_INFINITY;
Vec_PtrForEachEntry( vFanins, pNode, i )
{
if ( pNode->Level > (unsigned)LevelMax )
continue;
Abc_NodeSetTravIdCurrent( pNode );
Vec_VecPush( vLevels, pNode->Level, pNode );
if ( LevelMin < (int)pNode->Level )
LevelMin = pNode->Level;
}
assert( LevelMin >= 0 );
// mark MFFC
if ( pRoot )
Abc_NodeMffcLabel( pRoot );
// go through the levels up
Vec_PtrClear( vResult );
Vec_VecForEachEntryStartStop( vLevels, pNode, i, k, LevelMin, LevelMax )
{
// if the node is not marked, it is not a fanin
if ( !Abc_NodeIsTravIdCurrent(pNode) )
{
// check if it belongs to the TFO
if ( !Abc_NodeIsTravIdCurrent(Abc_ObjFanin0(pNode)) ||
!Abc_NodeIsTravIdCurrent(Abc_ObjFanin1(pNode)) )
continue;
// save the node in the TFO and label it
Vec_PtrPush( vResult, pNode );
Abc_NodeSetTravIdCurrent( pNode );
}
// go through the fanouts and add them to the structure if they meet the conditions
Abc_ObjForEachFanout( pNode, pFanout, v )
{
// skip if fanout is a CO or its level exceeds
if ( Abc_ObjIsCo(pFanout) || pFanout->Level > (unsigned)LevelMax )
continue;
// skip if it is already added or if it is in MFFC
if ( Abc_NodeIsTravIdCurrent(pFanout) )
continue;
// add it to the structure but do not mark it (until tested later)
Vec_VecPush( vLevels, pFanout->Level, pFanout );
}
}
// clear the levelized structure
Vec_VecForEachLevelStartStop( vLevels, vVec, i, LevelMin, LevelMax )
Vec_PtrClear( vVec );
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
|
