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/**CFile****************************************************************
FileName [bdcDec.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Truth-table-based bi-decomposition engine.]
Synopsis [Decomposition procedures.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - January 30, 2007.]
Revision [$Id: bdcDec.c,v 1.00 2007/01/30 00:00:00 alanmi Exp $]
***********************************************************************/
#include "bdcInt.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
static Bdc_Type_t Bdc_DecomposeStep( Bdc_Man_t * p, Bdc_Isf_t * pIsf, Bdc_Isf_t * pIsfL, Bdc_Isf_t * pIsfR );
static int Bdc_DecomposeUpdateRight( Bdc_Man_t * p, Bdc_Isf_t * pIsf, Bdc_Isf_t * pIsfL, Bdc_Isf_t * pIsfR, unsigned * puTruth, Bdc_Type_t Type );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Performs one step of bi-decomposition.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Bdc_Fun_t * Bdc_ManDecompose_rec( Bdc_Man_t * p, Bdc_Isf_t * pIsf )
{
Bdc_Fun_t * pFunc;
Bdc_Isf_t IsfL, * pIsfL = &IsfL;
Bdc_Isf_t IsfB, * pIsfR = &IsfB;
// check computed results
if ( pFunc = Bdc_TableLookup( p, pIsf ) )
return pFunc;
// decide on the decomposition type
pFunc = Bdc_FunNew( p );
if ( pFunc == NULL )
return NULL;
pFunc->Type = Bdc_DecomposeStep( p, pIsf, pIsfL, pIsfR );
// decompose the left branch
pFunc->pFan0 = Bdc_ManDecompose_rec( p, pIsfL );
if ( pFunc->pFan0 == NULL )
return NULL;
// decompose the right branch
if ( Bdc_DecomposeUpdateRight( p, pIsf, pIsfL, pIsfR, pFunc->pFan0->puFunc, pFunc->Type ) )
{
p->nNodes--;
return pFunc->pFan0;
}
pFunc->pFan1 = Bdc_ManDecompose_rec( p, pIsfL );
if ( pFunc->pFan1 == NULL )
return NULL;
// compute the function of node
pFunc->puFunc = (unsigned *)Vec_IntFetch(p->vMemory, p->nWords);
if ( pFunc->Type == BDC_TYPE_AND )
Kit_TruthAnd( pFunc->puFunc, pFunc->pFan0->puFunc, pFunc->pFan1->puFunc, p->nVars );
else if ( pFunc->Type == BDC_TYPE_OR )
Kit_TruthOr( pFunc->puFunc, pFunc->pFan0->puFunc, pFunc->pFan1->puFunc, p->nVars );
else
assert( 0 );
// verify correctness
assert( Bdc_TableCheckContainment(p, pIsf, pFunc->puFunc) );
// convert from OR to AND
if ( pFunc->Type == BDC_TYPE_OR )
{
pFunc->Type = BDC_TYPE_AND;
pFunc->pFan0 = Bdc_Not(pFunc->pFan0);
pFunc->pFan1 = Bdc_Not(pFunc->pFan1);
Kit_TruthNot( pFunc->puFunc, pFunc->puFunc, p->nVars );
pFunc = Bdc_Not(pFunc);
}
Bdc_TableAdd( p, Bdc_Regular(pFunc) );
return pFunc;
}
/**Function*************************************************************
Synopsis [Updates the ISF of the right after the left was decompoosed.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Bdc_DecomposeUpdateRight( Bdc_Man_t * p, Bdc_Isf_t * pIsf, Bdc_Isf_t * pIsfL, Bdc_Isf_t * pIsfR, unsigned * puTruth, Bdc_Type_t Type )
{
if ( Type == BDC_TYPE_OR )
{
// Right.Q = bdd_appex( Q, CompSpecLeftF, bddop_diff, setRightRes );
// Right.R = bdd_exist( R, setRightRes );
// if ( pR->Q ) Cudd_RecursiveDeref( dd, pR->Q );
// if ( pR->R ) Cudd_RecursiveDeref( dd, pR->R );
// pR->Q = Cudd_bddAndAbstract( dd, pF->Q, Cudd_Not(CompSpecF), pL->V ); Cudd_Ref( pR->Q );
// pR->R = Cudd_bddExistAbstract( dd, pF->R, pL->V ); Cudd_Ref( pR->R );
// assert( pR->R != b0 );
// return (int)( pR->Q == b0 );
Kit_TruthSharp( pIsfR->puOn, pIsf->puOn, puTruth, p->nVars );
Kit_TruthExistSet( pIsfR->puOn, pIsfR->puOn, p->nVars, pIsfL->uSupp );
Kit_TruthExistSet( pIsfR->puOff, pIsf->puOff, p->nVars, pIsfL->uSupp );
assert( !Kit_TruthIsConst0(pIsfR->puOff, p->nVars) );
return Kit_TruthIsConst0(pIsfR->puOn, p->nVars);
}
else if ( Type == BDC_TYPE_AND )
{
// Right.R = bdd_appex( R, CompSpecLeftF, bddop_and, setRightRes );
// Right.Q = bdd_exist( Q, setRightRes );
// if ( pR->Q ) Cudd_RecursiveDeref( dd, pR->Q );
// if ( pR->R ) Cudd_RecursiveDeref( dd, pR->R );
// pR->R = Cudd_bddAndAbstract( dd, pF->R, CompSpecF, pL->V ); Cudd_Ref( pR->R );
// pR->Q = Cudd_bddExistAbstract( dd, pF->Q, pL->V ); Cudd_Ref( pR->Q );
// assert( pR->Q != b0 );
// return (int)( pR->R == b0 );
Kit_TruthSharp( pIsfR->puOn, pIsf->puOn, puTruth, p->nVars );
Kit_TruthExistSet( pIsfR->puOn, pIsfR->puOn, p->nVars, pIsfL->uSupp );
Kit_TruthExistSet( pIsfR->puOff, pIsf->puOff, p->nVars, pIsfL->uSupp );
assert( !Kit_TruthIsConst0(pIsfR->puOff, p->nVars) );
return Kit_TruthIsConst0(pIsfR->puOn, p->nVars);
}
return 0;
}
/**Function*************************************************************
Synopsis [Checks existence of OR-bidecomposition.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
static inline int Bdc_DecomposeGetCost( Bdc_Man_t * p, int nLeftVars, int nRightVars )
{
assert( nLeftVars > 0 );
assert( nRightVars > 0 );
// compute the decomposition coefficient
if ( nLeftVars >= nRightVars )
return BDC_SCALE * (p->nVars * nRightVars + nLeftVars);
else // if ( nLeftVars < nRightVars )
return BDC_SCALE * (p->nVars * nLeftVars + nRightVars);
}
/**Function*************************************************************
Synopsis [Checks existence of weak OR-bidecomposition.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Bdc_DecomposeFindInitialVarSet( Bdc_Man_t * p, Bdc_Isf_t * pIsf, Bdc_Isf_t * pIsfL, Bdc_Isf_t * pIsfR )
{
char pVars[16];
int v, nVars, Beg, End;
assert( pIsfL->uSupp == 0 );
assert( pIsfR->uSupp == 0 );
// fill in the variables
nVars = 0;
for ( v = 0; v < p->nVars; v++ )
if ( pIsf->uSupp & (1 << v) )
pVars[nVars++] = v;
// try variable pairs
for ( Beg = 0; Beg < nVars; Beg++ )
{
Kit_TruthExistNew( p->puTemp1, pIsf->puOff, p->nVars, pVars[Beg] );
for ( End = nVars - 1; End > Beg; End-- )
{
Kit_TruthExistNew( p->puTemp2, pIsf->puOff, p->nVars, pVars[End] );
if ( Kit_TruthIsDisjoint3(pIsf->puOn, p->puTemp1, p->puTemp2, p->nVars) )
{
pIsfL->uSupp = (1 << Beg);
pIsfR->uSupp = (1 << End);
pIsfL->Var = Beg;
pIsfR->Var = End;
return 1;
}
}
}
return 0;
}
/**Function*************************************************************
Synopsis [Checks existence of weak OR-bidecomposition.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Bdc_DecomposeWeakOr( Bdc_Man_t * p, Bdc_Isf_t * pIsf, Bdc_Isf_t * pIsfL, Bdc_Isf_t * pIsfR )
{
int v, VarCost, VarBest, Cost, VarCostBest = 0;
for ( v = 0; v < p->nVars; v++ )
{
Kit_TruthExistNew( p->puTemp1, pIsf->puOff, p->nVars, v );
// if ( (Q & !bdd_exist( R, VarSetXa )) != bddfalse )
// Exist = Cudd_bddExistAbstract( dd, pF->R, Var ); Cudd_Ref( Exist );
// if ( Cudd_bddIteConstant( dd, pF->Q, Cudd_Not(Exist), b0 ) != b0 )
if ( !Kit_TruthIsImply( pIsf->puOn, p->puTemp1, p->nVars ) )
{
// measure the cost of this variable
// VarCost = bdd_satcountset( bdd_forall( Q, VarSetXa ), VarCube );
// Univ = Cudd_bddUnivAbstract( dd, pF->Q, Var ); Cudd_Ref( Univ );
// VarCost = Kit_TruthCountOnes( Univ, p->nVars );
// Cudd_RecursiveDeref( dd, Univ );
Kit_TruthForallNew( p->puTemp2, pIsf->puOn, p->nVars, v );
VarCost = Kit_TruthCountOnes( p->puTemp2, p->nVars );
if ( VarCost == 0 )
VarCost = 1;
if ( VarCostBest < VarCost )
{
VarCostBest = VarCost;
VarBest = v;
}
}
}
// derive the components for weak-bi-decomposition if the variable is found
if ( VarCostBest )
{
// funQLeftRes = Q & bdd_exist( R, setRightORweak );
// Temp = Cudd_bddExistAbstract( dd, pF->R, VarBest ); Cudd_Ref( Temp );
// pL->Q = Cudd_bddAnd( dd, pF->Q, Temp ); Cudd_Ref( pL->Q );
// Cudd_RecursiveDeref( dd, Temp );
Kit_TruthExistNew( p->puTemp1, pIsf->puOff, p->nVars, VarBest );
Kit_TruthAnd( pIsfL->puOn, pIsf->puOn, p->puTemp1, p->nVars );
// pL->R = pF->R; Cudd_Ref( pL->R );
// pL->V = VarBest; Cudd_Ref( pL->V );
Kit_TruthCopy( pIsfL->puOff, pIsf->puOff, p->nVars );
pIsfL->Var = VarBest;
// assert( pL->Q != b0 );
// assert( pL->R != b0 );
// assert( Cudd_bddIteConstant( dd, pL->Q, pL->R, b0 ) == b0 );
// express cost in percents of the covered boolean space
Cost = VarCostBest * BDC_SCALE / (1<<p->nVars);
if ( Cost == 0 )
Cost = 1;
return Cost;
}
return 0;
}
/**Function*************************************************************
Synopsis [Checks existence of OR-bidecomposition.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Bdc_DecomposeOr( Bdc_Man_t * p, Bdc_Isf_t * pIsf, Bdc_Isf_t * pIsfL, Bdc_Isf_t * pIsfR )
{
unsigned uSuppRem;
int v, nLeftVars = 1, nRightVars = 1;
// clean the var sets
Bdc_IsfClean( pIsfL );
Bdc_IsfClean( pIsfR );
// find initial variable sets
if ( !Bdc_DecomposeFindInitialVarSet( p, pIsf, pIsfL, pIsfR ) )
return Bdc_DecomposeWeakOr( p, pIsf, pIsfL, pIsfR );
// prequantify the variables in the offset
Kit_TruthExistNew( p->puTemp1, pIsf->puOff, p->nVars, pIsfL->Var );
Kit_TruthExistNew( p->puTemp2, pIsf->puOff, p->nVars, pIsfR->Var );
// go through the remaining variables
uSuppRem = pIsf->uSupp & ~pIsfL->uSupp & ~pIsfR->uSupp;
assert( Kit_WordCountOnes(uSuppRem) > 0 );
for ( v = 0; v < p->nVars; v++ )
{
if ( (uSuppRem & (1 << v)) == 0 )
continue;
// prequantify this variable
Kit_TruthExistNew( p->puTemp3, p->puTemp1, p->nVars, v );
Kit_TruthExistNew( p->puTemp4, p->puTemp2, p->nVars, v );
if ( nLeftVars < nRightVars )
{
// if ( (Q & bdd_exist( pF->R, pL->V & VarNew ) & bdd_exist( pF->R, pR->V )) == bddfalse )
// if ( VerifyORCondition( dd, pF->Q, pF->R, pL->V, pR->V, VarNew ) )
if ( Kit_TruthIsDisjoint3(pIsf->puOn, p->puTemp3, p->puTemp2, p->nVars) )
{
// pL->V &= VarNew;
pIsfL->uSupp |= (1 << v);
nLeftVars++;
}
// else if ( (Q & bdd_exist( pF->R, pR->V & VarNew ) & bdd_exist( pF->R, pL->V )) == bddfalse )
else if ( Kit_TruthIsDisjoint3(pIsf->puOn, p->puTemp4, p->puTemp1, p->nVars) )
{
// pR->V &= VarNew;
pIsfR->uSupp |= (1 << v);
nRightVars++;
}
}
else
{
// if ( (Q & bdd_exist( pF->R, pR->V & VarNew ) & bdd_exist( pF->R, pL->V )) == bddfalse )
if ( Kit_TruthIsDisjoint3(pIsf->puOn, p->puTemp4, p->puTemp1, p->nVars) )
{
// pR->V &= VarNew;
pIsfR->uSupp |= (1 << v);
nRightVars++;
}
// else if ( (Q & bdd_exist( pF->R, pL->V & VarNew ) & bdd_exist( pF->R, pR->V )) == bddfalse )
else if ( Kit_TruthIsDisjoint3(pIsf->puOn, p->puTemp3, p->puTemp2, p->nVars) )
{
// pL->V &= VarNew;
pIsfL->uSupp |= (1 << v);
nLeftVars++;
}
}
}
// derive the functions Q and R for the left branch
// pL->Q = bdd_appex( pF->Q, bdd_exist( pF->R, pL->V ), bddop_and, pR->V );
// pL->R = bdd_exist( pF->R, pR->V );
// Temp = Cudd_bddExistAbstract( dd, pF->R, pL->V ); Cudd_Ref( Temp );
// pL->Q = Cudd_bddAndAbstract( dd, pF->Q, Temp, pR->V ); Cudd_Ref( pL->Q );
// Cudd_RecursiveDeref( dd, Temp );
// pL->R = Cudd_bddExistAbstract( dd, pF->R, pR->V ); Cudd_Ref( pL->R );
Kit_TruthAnd( pIsfL->puOn, pIsf->puOn, p->puTemp1, p->nVars );
Kit_TruthExistSet( pIsfL->puOn, pIsfL->puOn, p->nVars, pIsfR->uSupp );
Kit_TruthCopy( pIsfL->puOff, p->puTemp2, p->nVars );
// derive the functions Q and R for the right branch
// Temp = Cudd_bddExistAbstract( dd, pF->R, pR->V ); Cudd_Ref( Temp );
// pR->Q = Cudd_bddAndAbstract( dd, pF->Q, Temp, pL->V ); Cudd_Ref( pR->Q );
// Cudd_RecursiveDeref( dd, Temp );
// pR->R = Cudd_bddExistAbstract( dd, pF->R, pL->V ); Cudd_Ref( pR->R );
/*
Kit_TruthAnd( pIsfR->puOn, pIsf->puOn, p->puTemp2, p->nVars );
Kit_TruthExistSet( pIsfR->puOn, pIsfR->puOn, p->nVars, pIsfL->uSupp );
Kit_TruthCopy( pIsfR->puOff, p->puTemp1, p->nVars );
*/
// assert( pL->Q != b0 );
// assert( pL->R != b0 );
// assert( Cudd_bddIteConstant( dd, pL->Q, pL->R, b0 ) == b0 );
assert( !Kit_TruthIsConst0(pIsfL->puOn, p->nVars) );
assert( !Kit_TruthIsConst0(pIsfL->puOff, p->nVars) );
assert( Kit_TruthIsDisjoint(pIsfL->puOn, pIsfL->puOff, p->nVars) );
return Bdc_DecomposeGetCost( p, nLeftVars, nRightVars );
}
/**Function*************************************************************
Synopsis [Performs one step of bi-decomposition.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Bdc_Type_t Bdc_DecomposeStep( Bdc_Man_t * p, Bdc_Isf_t * pIsf, Bdc_Isf_t * pIsfL, Bdc_Isf_t * pIsfR )
{
int CostOr, CostAnd, CostOrL, CostOrR, CostAndL, CostAndR;
Bdc_IsfClean( p->pIsfOL );
Bdc_IsfClean( p->pIsfOR );
Bdc_IsfClean( p->pIsfAL );
Bdc_IsfClean( p->pIsfAR );
// perform OR decomposition
CostOr = Bdc_DecomposeOr( p, pIsf, p->pIsfOL, p->pIsfOR );
// perform AND decomposition
Bdc_IsfNot( pIsf );
CostAnd = Bdc_DecomposeOr( p, pIsf, p->pIsfAL, p->pIsfAR );
Bdc_IsfNot( pIsf );
Bdc_IsfNot( p->pIsfAL );
Bdc_IsfNot( p->pIsfAR );
// check the hash table
Bdc_SuppMinimize( p, p->pIsfOL );
CostOrL = (Bdc_TableLookup(p, p->pIsfOL) != NULL);
Bdc_SuppMinimize( p, p->pIsfOR );
CostOrR = (Bdc_TableLookup(p, p->pIsfOR) != NULL);
Bdc_SuppMinimize( p, p->pIsfAL );
CostAndL = (Bdc_TableLookup(p, p->pIsfAL) != NULL);
Bdc_SuppMinimize( p, p->pIsfAR );
CostAndR = (Bdc_TableLookup(p, p->pIsfAR) != NULL);
// check if there is any reuse for the components
if ( CostOrL + CostOrR < CostAndL + CostAndR )
{
Bdc_IsfCopy( pIsfL, p->pIsfOL );
Bdc_IsfCopy( pIsfR, p->pIsfOR );
return BDC_TYPE_OR;
}
if ( CostOrL + CostOrR > CostAndL + CostAndR )
{
Bdc_IsfCopy( pIsfL, p->pIsfAL );
Bdc_IsfCopy( pIsfR, p->pIsfAR );
return BDC_TYPE_AND;
}
// compare the two-component costs
if ( CostOr < CostAnd )
{
Bdc_IsfCopy( pIsfL, p->pIsfOL );
Bdc_IsfCopy( pIsfR, p->pIsfOR );
return BDC_TYPE_OR;
}
return BDC_TYPE_AND;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
|
