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/**CFile****************************************************************
FileName [abcUnreach.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Network and node package.]
Synopsis [Computes unreachable states for small benchmarks.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: abcUnreach.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "abc.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
static DdNode * Abc_NtkTransitionRelation( DdManager * dd, Abc_Ntk_t * pNtk, int fVerbose );
static DdNode * Abc_NtkInitStateAndVarMap( DdManager * dd, Abc_Ntk_t * pNtk, int fVerbose );
static DdNode * Abc_NtkComputeUnreachable( DdManager * dd, Abc_Ntk_t * pNtk, DdNode * bRelation, DdNode * bInitial, bool fVerbose );
static Abc_Ntk_t * Abc_NtkConstructExdc ( DdManager * dd, Abc_Ntk_t * pNtk, DdNode * bUnreach );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Extracts sequential DCs of the network.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NtkExtractSequentialDcs( Abc_Ntk_t * pNtk, bool fVerbose )
{
int fReorder = 1;
DdManager * dd;
DdNode * bRelation, * bInitial, * bUnreach;
// remove EXDC network if present
if ( pNtk->pExdc )
{
Abc_NtkDelete( pNtk->pExdc );
pNtk->pExdc = NULL;
}
// compute the global BDDs of the latches
dd = Abc_NtkGlobalBdds( pNtk, 1 );
if ( dd == NULL )
return 0;
if ( fVerbose )
printf( "The shared BDD size is %d nodes.\n", Cudd_ReadKeys(dd) - Cudd_ReadDead(dd) );
// create the transition relation (dereferenced global BDDs)
bRelation = Abc_NtkTransitionRelation( dd, pNtk, fVerbose ); Cudd_Ref( bRelation );
// create the initial state and the variable map
bInitial = Abc_NtkInitStateAndVarMap( dd, pNtk, fVerbose ); Cudd_Ref( bInitial );
// compute the unreachable states
bUnreach = Abc_NtkComputeUnreachable( dd, pNtk, bRelation, bInitial, fVerbose ); Cudd_Ref( bUnreach );
Cudd_RecursiveDeref( dd, bRelation );
Cudd_RecursiveDeref( dd, bInitial );
// reorder and disable reordering
if ( fReorder )
{
if ( fVerbose )
fprintf( stdout, "BDD nodes in the unreachable states before reordering %d.\n", Cudd_DagSize(bUnreach) );
Cudd_ReduceHeap( dd, CUDD_REORDER_SYMM_SIFT, 1 );
Cudd_AutodynDisable( dd );
if ( fVerbose )
fprintf( stdout, "BDD nodes in the unreachable states after reordering %d.\n", Cudd_DagSize(bUnreach) );
}
// allocate ZDD variables
Cudd_zddVarsFromBddVars( dd, 2 );
// create the EXDC network representing the unreachable states
pNtk->pExdc = Abc_NtkConstructExdc( dd, pNtk, bUnreach );
Cudd_RecursiveDeref( dd, bUnreach );
Extra_StopManager( dd );
pNtk->pManGlob = NULL;
// make sure that everything is okay
if ( !Abc_NtkCheck( pNtk->pExdc ) )
{
printf( "Abc_NtkExtractSequentialDcs: The network check has failed.\n" );
Abc_NtkDelete( pNtk->pExdc );
return 0;
}
return 1;
}
/**Function*************************************************************
Synopsis [Computes the transition relation of the network.]
Description [Assumes that the global BDDs are computed.]
SideEffects []
SeeAlso []
***********************************************************************/
DdNode * Abc_NtkTransitionRelation( DdManager * dd, Abc_Ntk_t * pNtk, int fVerbose )
{
DdNode * bRel, * bTemp, * bProd, * bVar, * bInputs;
Abc_Obj_t * pNode;
int fReorder = 1;
int i;
// extand the BDD manager to represent NS variables
assert( dd->size == Abc_NtkCiNum(pNtk) );
Cudd_bddIthVar( dd, Abc_NtkCiNum(pNtk) + Abc_NtkLatchNum(pNtk) - 1 );
// enable reordering
if ( fReorder )
Cudd_AutodynEnable( dd, CUDD_REORDER_SYMM_SIFT );
else
Cudd_AutodynDisable( dd );
// compute the transition relation
bRel = b1; Cudd_Ref( bRel );
Abc_NtkForEachLatch( pNtk, pNode, i )
{
bVar = Cudd_bddIthVar( dd, Abc_NtkCiNum(pNtk) + i );
bProd = Cudd_bddXnor( dd, bVar, pNtk->vFuncsGlob->pArray[i] ); Cudd_Ref( bProd );
bRel = Cudd_bddAnd( dd, bTemp = bRel, bProd ); Cudd_Ref( bRel );
Cudd_RecursiveDeref( dd, bTemp );
Cudd_RecursiveDeref( dd, bProd );
}
// free the global BDDs
Abc_NtkFreeGlobalBdds( pNtk );
// quantify the PI variables
bInputs = Extra_bddComputeRangeCube( dd, 0, Abc_NtkPiNum(pNtk) ); Cudd_Ref( bInputs );
bRel = Cudd_bddExistAbstract( dd, bTemp = bRel, bInputs ); Cudd_Ref( bRel );
Cudd_RecursiveDeref( dd, bTemp );
Cudd_RecursiveDeref( dd, bInputs );
// reorder and disable reordering
if ( fReorder )
{
if ( fVerbose )
fprintf( stdout, "BDD nodes in the transition relation before reordering %d.\n", Cudd_DagSize(bRel) );
Cudd_ReduceHeap( dd, CUDD_REORDER_SYMM_SIFT, 100 );
Cudd_AutodynDisable( dd );
if ( fVerbose )
fprintf( stdout, "BDD nodes in the transition relation after reordering %d.\n", Cudd_DagSize(bRel) );
}
Cudd_Deref( bRel );
return bRel;
}
/**Function*************************************************************
Synopsis [Computes the initial state and sets up the variable map.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
DdNode * Abc_NtkInitStateAndVarMap( DdManager * dd, Abc_Ntk_t * pNtk, int fVerbose )
{
DdNode ** pbVarsX, ** pbVarsY;
DdNode * bTemp, * bProd, * bVar;
Abc_Obj_t * pLatch;
int i;
// set the variable mapping for Cudd_bddVarMap()
pbVarsX = ALLOC( DdNode *, dd->size );
pbVarsY = ALLOC( DdNode *, dd->size );
bProd = b1; Cudd_Ref( bProd );
Abc_NtkForEachLatch( pNtk, pLatch, i )
{
pbVarsX[i] = dd->vars[ Abc_NtkPiNum(pNtk) + i ];
pbVarsY[i] = dd->vars[ Abc_NtkCiNum(pNtk) + i ];
// get the initial value of the latch
bVar = Cudd_NotCond( pbVarsX[i], !Abc_LatchIsInit1(pLatch) );
bProd = Cudd_bddAnd( dd, bTemp = bProd, bVar ); Cudd_Ref( bProd );
Cudd_RecursiveDeref( dd, bTemp );
}
Cudd_SetVarMap( dd, pbVarsX, pbVarsY, Abc_NtkLatchNum(pNtk) );
FREE( pbVarsX );
FREE( pbVarsY );
Cudd_Deref( bProd );
return bProd;
}
/**Function*************************************************************
Synopsis [Computes the set of unreachable states.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
DdNode * Abc_NtkComputeUnreachable( DdManager * dd, Abc_Ntk_t * pNtk, DdNode * bTrans, DdNode * bInitial, bool fVerbose )
{
DdNode * bRelation, * bReached, * bCubeCs;
DdNode * bCurrent, * bNext, * bTemp;
int nIters;
// perform reachability analisys
bCurrent = bInitial; Cudd_Ref( bCurrent );
bReached = bInitial; Cudd_Ref( bReached );
bRelation = bTrans; Cudd_Ref( bRelation );
bCubeCs = Extra_bddComputeRangeCube( dd, Abc_NtkPiNum(pNtk), Abc_NtkCiNum(pNtk) ); Cudd_Ref( bCubeCs );
for ( nIters = 1; ; nIters++ )
{
// compute the next states
bNext = Cudd_bddAndAbstract( dd, bRelation, bCurrent, bCubeCs ); Cudd_Ref( bNext );
Cudd_RecursiveDeref( dd, bCurrent );
// remap these states into the current state vars
bNext = Cudd_bddVarMap( dd, bTemp = bNext ); Cudd_Ref( bNext );
Cudd_RecursiveDeref( dd, bTemp );
// check if there are any new states
if ( Cudd_bddLeq( dd, bNext, bReached ) )
break;
// get the new states
bCurrent = Cudd_bddAnd( dd, bNext, Cudd_Not(bReached) ); Cudd_Ref( bCurrent );
// minimize the new states with the reached states
// bCurrent = Cudd_bddConstrain( dd, bTemp = bCurrent, Cudd_Not(bReached) ); Cudd_Ref( bCurrent );
// Cudd_RecursiveDeref( dd, bTemp );
// add to the reached states
bReached = Cudd_bddOr( dd, bTemp = bReached, bNext ); Cudd_Ref( bReached );
Cudd_RecursiveDeref( dd, bTemp );
Cudd_RecursiveDeref( dd, bNext );
// minimize the transition relation
// bRelation = Cudd_bddConstrain( dd, bTemp = bRelation, Cudd_Not(bReached) ); Cudd_Ref( bRelation );
// Cudd_RecursiveDeref( dd, bTemp );
}
Cudd_RecursiveDeref( dd, bRelation );
Cudd_RecursiveDeref( dd, bCubeCs );
Cudd_RecursiveDeref( dd, bNext );
// report the stats
if ( fVerbose )
{
fprintf( stdout, "Reachability analysis completed in %d iterations.\n", nIters );
fprintf( stdout, "The number of minterms in the reachable state set = %d.\n",
(int)Cudd_CountMinterm(dd, bReached, Abc_NtkLatchNum(pNtk) ) );
}
//PRB( dd, bReached );
Cudd_Deref( bReached );
return Cudd_Not( bReached );
}
/**Function*************************************************************
Synopsis [Creates the EXDC network.]
Description [The set of unreachable states depends on CS variables.]
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Ntk_t * Abc_NtkConstructExdc( DdManager * dd, Abc_Ntk_t * pNtk, DdNode * bUnreach )
{
Abc_Ntk_t * pNtkNew;
Abc_Obj_t * pNode, * pNodeNew;
int * pPermute;
int i;
// start the new network
pNtkNew = Abc_NtkAlloc( ABC_TYPE_LOGIC, ABC_FUNC_BDD );
// create PIs corresponding to LOs
Abc_NtkForEachLatch( pNtk, pNode, i )
pNode->pCopy = Abc_NtkCreatePi(pNtkNew);
// create a new node
pNodeNew = Abc_NtkCreateNode(pNtkNew);
// add the fanins corresponding to latch outputs
Abc_NtkForEachLatch( pNtk, pNode, i )
Abc_ObjAddFanin( pNodeNew, pNode->pCopy );
// create the logic function
pPermute = ALLOC( int, dd->size );
for ( i = 0; i < dd->size; i++ )
pPermute[i] = -1;
Abc_NtkForEachLatch( pNtk, pNode, i )
pPermute[Abc_NtkPiNum(pNtk) + i] = i;
// remap the functions
pNodeNew->pData = Extra_TransferPermute( dd, pNtkNew->pManFunc, bUnreach, pPermute ); Cudd_Ref( pNodeNew->pData );
free( pPermute );
Abc_NodeMinimumBase( pNodeNew );
// make the new node drive all the COs
Abc_NtkForEachCo( pNtk, pNode, i )
Abc_ObjAddFanin( Abc_NtkCreatePo(pNtkNew), pNodeNew );
// store the PI names of the EXDC network
Abc_NtkForEachLatch( pNtk, pNode, i )
Abc_NtkLogicStoreName( Abc_NtkPi(pNtkNew,i), Abc_ObjName(pNode) );
// store the PO names of the EXDC network
Abc_NtkForEachPo( pNtk, pNode, i )
Abc_NtkLogicStoreName( Abc_NtkPo(pNtkNew,i), Abc_ObjName(pNode) );
Abc_NtkForEachLatch( pNtk, pNode, i )
Abc_NtkLogicStoreName( Abc_NtkCo(pNtkNew,Abc_NtkPoNum(pNtk) + i), Abc_ObjNameSuffix(pNode, "_in") );
// make the network minimum base
Abc_NtkMinimumBase( pNtkNew );
// fix the problem with complemented and duplicated CO edges
Abc_NtkLogicMakeSimpleCos( pNtkNew, 0 );
// transform the network to the SOP representation
Abc_NtkBddToSop( pNtkNew );
return pNtkNew;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
|
