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/**CFile****************************************************************
FileName [bbrReach.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [BDD-based reachability analysis.]
Synopsis [Procedures to perform reachability analysis.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: bbrReach.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "bbr.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function********************************************************************
Synopsis [Performs the reordering-sensitive step of Extra_bddMove().]
Description []
SideEffects []
SeeAlso []
******************************************************************************/
DdNode * Bbr_bddComputeRangeCube( DdManager * dd, int iStart, int iStop )
{
DdNode * bTemp, * bProd;
int i;
assert( iStart <= iStop );
assert( iStart >= 0 && iStart <= dd->size );
assert( iStop >= 0 && iStop <= dd->size );
bProd = (dd)->one; Cudd_Ref( bProd );
for ( i = iStart; i < iStop; i++ )
{
bProd = Cudd_bddAnd( dd, bTemp = bProd, dd->vars[i] ); Cudd_Ref( bProd );
Cudd_RecursiveDeref( dd, bTemp );
}
Cudd_Deref( bProd );
return bProd;
}
/**Function*************************************************************
Synopsis []
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Bbr_StopManager( DdManager * dd )
{
int RetValue;
// check for remaining references in the package
RetValue = Cudd_CheckZeroRef( dd );
if ( RetValue > 0 )
printf( "\nThe number of referenced nodes = %d\n\n", RetValue );
// Cudd_PrintInfo( dd, stdout );
Cudd_Quit( dd );
}
/**Function*************************************************************
Synopsis [Computes the initial state and sets up the variable map.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
DdNode * Aig_ManInitStateVarMap( DdManager * dd, Aig_Man_t * p, int fVerbose )
{
DdNode ** pbVarsX, ** pbVarsY;
DdNode * bTemp, * bProd;
Aig_Obj_t * pLatch;
int i;
// set the variable mapping for Cudd_bddVarMap()
pbVarsX = ALLOC( DdNode *, dd->size );
pbVarsY = ALLOC( DdNode *, dd->size );
bProd = (dd)->one; Cudd_Ref( bProd );
Saig_ManForEachLo( p, pLatch, i )
{
pbVarsX[i] = dd->vars[ Saig_ManPiNum(p) + i ];
pbVarsY[i] = dd->vars[ Saig_ManCiNum(p) + i ];
// get the initial value of the latch
bProd = Cudd_bddAnd( dd, bTemp = bProd, Cudd_Not(pbVarsX[i]) ); Cudd_Ref( bProd );
Cudd_RecursiveDeref( dd, bTemp );
}
Cudd_SetVarMap( dd, pbVarsX, pbVarsY, Saig_ManRegNum(p) );
FREE( pbVarsX );
FREE( pbVarsY );
Cudd_Deref( bProd );
return bProd;
}
/**Function*************************************************************
Synopsis [Collects the array of output BDDs.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
DdNode ** Aig_ManCreateOutputs( DdManager * dd, Aig_Man_t * p )
{
DdNode ** pbOutputs;
Aig_Obj_t * pNode;
int i;
// compute the transition relation
pbOutputs = ALLOC( DdNode *, Saig_ManPoNum(p) );
Saig_ManForEachPo( p, pNode, i )
{
pbOutputs[i] = Aig_ObjGlobalBdd(pNode); Cudd_Ref( pbOutputs[i] );
}
return pbOutputs;
}
/**Function*************************************************************
Synopsis [Collects the array of partition BDDs.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
DdNode ** Aig_ManCreatePartitions( DdManager * dd, Aig_Man_t * p, int fReorder, int fVerbose )
{
DdNode ** pbParts;
DdNode * bVar;
Aig_Obj_t * pNode;
int i;
// extand the BDD manager to represent NS variables
assert( dd->size == Saig_ManCiNum(p) );
Cudd_bddIthVar( dd, Saig_ManCiNum(p) + Saig_ManRegNum(p) - 1 );
// enable reordering
if ( fReorder )
Cudd_AutodynEnable( dd, CUDD_REORDER_SYMM_SIFT );
else
Cudd_AutodynDisable( dd );
// compute the transition relation
pbParts = ALLOC( DdNode *, Saig_ManRegNum(p) );
Saig_ManForEachLi( p, pNode, i )
{
bVar = Cudd_bddIthVar( dd, Saig_ManCiNum(p) + i );
pbParts[i] = Cudd_bddXnor( dd, bVar, Aig_ObjGlobalBdd(pNode) ); Cudd_Ref( pbParts[i] );
}
// free global BDDs
Aig_ManFreeGlobalBdds( p, dd );
// reorder and disable reordering
if ( fReorder )
{
if ( fVerbose )
fprintf( stdout, "BDD nodes in the partitions before reordering %d.\n", Cudd_SharingSize(pbParts,Saig_ManRegNum(p)) );
Cudd_ReduceHeap( dd, CUDD_REORDER_SYMM_SIFT, 100 );
Cudd_AutodynDisable( dd );
if ( fVerbose )
fprintf( stdout, "BDD nodes in the partitions after reordering %d.\n", Cudd_SharingSize(pbParts,Saig_ManRegNum(p)) );
}
return pbParts;
}
/**Function*************************************************************
Synopsis [Computes the set of unreachable states.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Aig_ManComputeReachable( DdManager * dd, Aig_Man_t * p, DdNode ** pbParts, DdNode * bInitial, DdNode ** pbOutputs, int nBddMax, int nIterMax, int fPartition, int fReorder, int fVerbose, int fSilent )
{
int fInternalReorder = 0;
Bbr_ImageTree_t * pTree;
Bbr_ImageTree2_t * pTree2;
DdNode * bReached, * bCubeCs;
DdNode * bCurrent, * bNext, * bTemp;
DdNode ** pbVarsY;
Aig_Obj_t * pLatch;
int i, nIters, nBddSize;
int nThreshold = 10000;
// collect the NS variables
// set the variable mapping for Cudd_bddVarMap()
pbVarsY = ALLOC( DdNode *, dd->size );
Saig_ManForEachLo( p, pLatch, i )
pbVarsY[i] = dd->vars[ Saig_ManCiNum(p) + i ];
// start the image computation
bCubeCs = Bbr_bddComputeRangeCube( dd, Saig_ManPiNum(p), Saig_ManCiNum(p) ); Cudd_Ref( bCubeCs );
if ( fPartition )
pTree = Bbr_bddImageStart( dd, bCubeCs, Saig_ManRegNum(p), pbParts, Saig_ManRegNum(p), pbVarsY, fVerbose );
else
pTree2 = Bbr_bddImageStart2( dd, bCubeCs, Saig_ManRegNum(p), pbParts, Saig_ManRegNum(p), pbVarsY, fVerbose );
Cudd_RecursiveDeref( dd, bCubeCs );
free( pbVarsY );
if ( pTree == NULL )
{
if ( !fSilent )
printf( "BDDs blew up during qualitification scheduling. " );
return -1;
}
// perform reachability analisys
bCurrent = bInitial; Cudd_Ref( bCurrent );
bReached = bInitial; Cudd_Ref( bReached );
for ( nIters = 1; nIters <= nIterMax; nIters++ )
{
// compute the next states
if ( fPartition )
bNext = Bbr_bddImageCompute( pTree, bCurrent );
else
bNext = Bbr_bddImageCompute2( pTree2, bCurrent );
if ( bNext == NULL )
{
if ( !fSilent )
printf( "BDDs blew up during image computation. " );
if ( fPartition )
Bbr_bddImageTreeDelete( pTree );
else
Bbr_bddImageTreeDelete2( pTree2 );
return -1;
}
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;
// check the BDD size
nBddSize = Cudd_DagSize(bNext);
if ( nBddSize > nBddMax )
break;
// check the result
for ( i = 0; i < Saig_ManPoNum(p); i++ )
{
if ( !Cudd_bddLeq( dd, bNext, Cudd_Not(pbOutputs[i]) ) )
{
if ( !fSilent )
printf( "Output %d was asserted in frame %d. ", i, nIters );
Cudd_RecursiveDeref( dd, bReached );
bReached = NULL;
break;
}
}
if ( i < Saig_ManPoNum(p) )
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 );
if ( fVerbose )
fprintf( stdout, "Frame = %3d. BDD = %5d. ", nIters, nBddSize );
if ( fInternalReorder && fReorder && nBddSize > nThreshold )
{
if ( fVerbose )
fprintf( stdout, "Reordering... Before = %5d. ", Cudd_DagSize(bReached) );
Cudd_ReduceHeap( dd, CUDD_REORDER_SYMM_SIFT, 100 );
Cudd_AutodynDisable( dd );
if ( fVerbose )
fprintf( stdout, "After = %5d.\r", Cudd_DagSize(bReached) );
nThreshold *= 2;
}
if ( fVerbose )
fprintf( stdout, "\r" );
}
Cudd_RecursiveDeref( dd, bNext );
// undo the image tree
if ( fPartition )
Bbr_bddImageTreeDelete( pTree );
else
Bbr_bddImageTreeDelete2( pTree2 );
if ( bReached == NULL )
return 0; // proved reachable
// report the stats
if ( fVerbose )
{
double nMints = Cudd_CountMinterm(dd, bReached, Saig_ManRegNum(p) );
if ( nIters > nIterMax || Cudd_DagSize(bReached) > nBddMax )
fprintf( stdout, "Reachability analysis is stopped after %d frames.\n", nIters );
else
fprintf( stdout, "Reachability analysis completed after %d frames.\n", nIters );
fprintf( stdout, "Reachable states = %.0f. (Ratio = %.4f %%)\n", nMints, 100.0*nMints/pow(2.0, Saig_ManRegNum(p)) );
fflush( stdout );
}
//PRB( dd, bReached );
Cudd_RecursiveDeref( dd, bReached );
if ( nIters > nIterMax || Cudd_DagSize(bReached) > nBddMax )
{
if ( !fSilent )
printf( "Verified only for states reachable in %d frames. ", nIters );
return -1; // undecided
}
if ( !fSilent )
printf( "The miter is proved unreachable after %d iterations. ", nIters );
return 1; // unreachable
}
/**Function*************************************************************
Synopsis [Performs reachability to see if any .]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Aig_ManVerifyUsingBdds( Aig_Man_t * p, int nBddMax, int nIterMax, int fPartition, int fReorder, int fVerbose, int fSilent )
{
DdManager * dd;
DdNode ** pbParts, ** pbOutputs;
DdNode * bInitial;
int RetValue, i, clk = clock();
assert( Saig_ManRegNum(p) > 0 );
// compute the global BDDs of the latches
dd = Aig_ManComputeGlobalBdds( p, nBddMax, 1, fReorder, fVerbose );
if ( dd == NULL )
{
if ( !fSilent )
printf( "The number of intermediate BDD nodes exceeded the limit (%d).\n", nBddMax );
return -1;
}
if ( fVerbose )
printf( "Shared BDD size is %6d nodes.\n", Cudd_ReadKeys(dd) - Cudd_ReadDead(dd) );
// save outputs
pbOutputs = Aig_ManCreateOutputs( dd, p );
// create partitions
pbParts = Aig_ManCreatePartitions( dd, p, fReorder, fVerbose );
// create the initial state and the variable map
bInitial = Aig_ManInitStateVarMap( dd, p, fVerbose ); Cudd_Ref( bInitial );
// check the result
RetValue = -1;
for ( i = 0; i < Saig_ManPoNum(p); i++ )
{
if ( !Cudd_bddLeq( dd, bInitial, Cudd_Not(pbOutputs[i]) ) )
{
if ( !fSilent )
printf( "The miter output %d is proved REACHABLE in the initial state. ", i );
RetValue = 0;
break;
}
}
// explore reachable states
if ( RetValue == -1 )
RetValue = Aig_ManComputeReachable( dd, p, pbParts, bInitial, pbOutputs, nBddMax, nIterMax, fPartition, fReorder, fVerbose, fSilent );
// cleanup
Cudd_RecursiveDeref( dd, bInitial );
for ( i = 0; i < Saig_ManRegNum(p); i++ )
Cudd_RecursiveDeref( dd, pbParts[i] );
free( pbParts );
for ( i = 0; i < Saig_ManPoNum(p); i++ )
Cudd_RecursiveDeref( dd, pbOutputs[i] );
free( pbOutputs );
if ( RetValue == -1 )
Cudd_Quit( dd );
else
Bbr_StopManager( dd );
// report the runtime
if ( !fSilent )
{
PRT( "Time", clock() - clk );
fflush( stdout );
}
return RetValue;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
|
