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/**CFile****************************************************************
FileName [bbrCex.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [BDD-based reachability analysis.]
Synopsis [Procedures to derive a satisfiable counter-example.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: bbrCex.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "bbr.h"
#include "ssw.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
extern DdNode * Bbr_bddComputeRangeCube( DdManager * dd, int iStart, int iStop );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Derives the counter-example using the set of reached states.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Ssw_Cex_t * Aig_ManVerifyUsingBddsCountExample( Aig_Man_t * p, DdManager * dd,
DdNode ** pbParts, Vec_Ptr_t * vOnionRings, DdNode * bCubeFirst,
int iOutput, int fVerbose, int fSilent )
{
Ssw_Cex_t * pCex;
Aig_Obj_t * pObj;
Bbr_ImageTree_t * pTree;
DdNode * bCubeNs, * bState, * bImage;
DdNode * bTemp, * bVar, * bRing;
int i, v, RetValue, nPiOffset;
char * pValues;
int clk = clock();
// allocate room for the counter-example
pCex = Ssw_SmlAllocCounterExample( Saig_ManRegNum(p), Saig_ManPiNum(p), Vec_PtrSize(vOnionRings)+1 );
pCex->iFrame = Vec_PtrSize(vOnionRings);
pCex->iPo = iOutput;
nPiOffset = Saig_ManRegNum(p) + Saig_ManPiNum(p) * Vec_PtrSize(vOnionRings);
// create the cube of NS variables
bCubeNs = Bbr_bddComputeRangeCube( dd, Saig_ManCiNum(p), Saig_ManCiNum(p)+Saig_ManRegNum(p) ); Cudd_Ref( bCubeNs );
pTree = Bbr_bddImageStart( dd, bCubeNs, Saig_ManRegNum(p), pbParts, Saig_ManCiNum(p), dd->vars, fVerbose );
Cudd_RecursiveDeref( dd, bCubeNs );
if ( pTree == NULL )
{
if ( !fSilent )
printf( "BDDs blew up during qualitification scheduling. " );
return NULL;
}
// allocate room for the cube
pValues = ALLOC( char, dd->size );
// get the last cube
RetValue = Cudd_bddPickOneCube( dd, bCubeFirst, pValues );
assert( RetValue );
// write PIs of counter-example
Saig_ManForEachPi( p, pObj, i )
if ( pValues[i] == 1 )
Aig_InfoSetBit( pCex->pData, nPiOffset + i );
nPiOffset -= Saig_ManPiNum(p);
// write state in terms of NS variables
bState = (dd)->one; Cudd_Ref( bState );
Saig_ManForEachLo( p, pObj, i )
{
bVar = Cudd_NotCond( dd->vars[Saig_ManCiNum(p)+i], pValues[Saig_ManPiNum(p)+i] != 1 );
bState = Cudd_bddAnd( dd, bTemp = bState, bVar ); Cudd_Ref( bState );
Cudd_RecursiveDeref( dd, bTemp );
}
// perform backward analysis
Vec_PtrForEachEntryReverse( vOnionRings, bRing, v )
{
// compute the next states
bImage = Bbr_bddImageCompute( pTree, bState );
if ( bImage == NULL )
{
Cudd_RecursiveDeref( dd, bState );
if ( !fSilent )
printf( "BDDs blew up during image computation. " );
Bbr_bddImageTreeDelete( pTree );
free( pValues );
return NULL;
}
Cudd_Ref( bImage );
Cudd_RecursiveDeref( dd, bState );
// intersect with the previous set
bImage = Cudd_bddAnd( dd, bTemp = bImage, bRing ); Cudd_Ref( bImage );
Cudd_RecursiveDeref( dd, bTemp );
// find any assignment of the BDD
RetValue = Cudd_bddPickOneCube( dd, bImage, pValues );
assert( RetValue );
Cudd_RecursiveDeref( dd, bImage );
// write PIs of counter-example
Saig_ManForEachPi( p, pObj, i )
if ( pValues[i] == 1 )
Aig_InfoSetBit( pCex->pData, nPiOffset + i );
nPiOffset -= Saig_ManPiNum(p);
// check that we get the init state
if ( v == 0 )
{
Saig_ManForEachLo( p, pObj, i )
assert( pValues[Saig_ManPiNum(p)+i] == 0 );
break;
}
// write state in terms of NS variables
bState = (dd)->one; Cudd_Ref( bState );
Saig_ManForEachLo( p, pObj, i )
{
bVar = Cudd_NotCond( dd->vars[Saig_ManCiNum(p)+i], pValues[Saig_ManPiNum(p)+i] != 1 );
bState = Cudd_bddAnd( dd, bTemp = bState, bVar ); Cudd_Ref( bState );
Cudd_RecursiveDeref( dd, bTemp );
}
}
// cleanup
Bbr_bddImageTreeDelete( pTree );
free( pValues );
// verify the counter example
if ( Vec_PtrSize(vOnionRings) < 1000 )
{
RetValue = Ssw_SmlRunCounterExample( p, pCex );
if ( RetValue == 0 && !fSilent )
printf( "Aig_ManVerifyUsingBdds(): Counter-example verification has FAILED.\n" );
}
if ( fVerbose && !fSilent )
{
PRT( "Counter-example generation time", clock() - clk );
}
return pCex;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
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