/**CFile****************************************************************
FileName [dchCnf.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Choice computation for tech-mapping.]
Synopsis [Computation of CNF.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 29, 2008.]
Revision [$Id: dchCnf.c,v 1.00 2008/07/29 00:00:00 alanmi Exp $]
***********************************************************************/
#include "dchInt.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Addes clauses to the solver.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Dch_AddClausesMux( Dch_Man_t * p, Aig_Obj_t * pNode )
{
Aig_Obj_t * pNodeI, * pNodeT, * pNodeE;
int pLits[4], RetValue, VarF, VarI, VarT, VarE, fCompT, fCompE;
assert( !Aig_IsComplement( pNode ) );
assert( Aig_ObjIsMuxType( pNode ) );
// get nodes (I = if, T = then, E = else)
pNodeI = Aig_ObjRecognizeMux( pNode, &pNodeT, &pNodeE );
// get the variable numbers
VarF = Dch_ObjSatNum(p,pNode);
VarI = Dch_ObjSatNum(p,pNodeI);
VarT = Dch_ObjSatNum(p,Aig_Regular(pNodeT));
VarE = Dch_ObjSatNum(p,Aig_Regular(pNodeE));
// get the complementation flags
fCompT = Aig_IsComplement(pNodeT);
fCompE = Aig_IsComplement(pNodeE);
// f = ITE(i, t, e)
// i' + t' + f
// i' + t + f'
// i + e' + f
// i + e + f'
// create four clauses
pLits[0] = toLitCond(VarI, 1);
pLits[1] = toLitCond(VarT, 1^fCompT);
pLits[2] = toLitCond(VarF, 0);
if ( p->pPars->fPolarFlip )
{
if ( pNodeI->fPhase ) pLits[0] = lit_neg( pLits[0] );
if ( Aig_Regular(pNodeT)->fPhase ) pLits[1] = lit_neg( pLits[1] );
if ( pNode->fPhase ) pLits[2] = lit_neg( pLits[2] );
}
RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
assert( RetValue );
pLits[0] = toLitCond(VarI, 1);
pLits[1] = toLitCond(VarT, 0^fCompT);
pLits[2] = toLitCond(VarF, 1);
if ( p->pPars->fPolarFlip )
{
if ( pNodeI->fPhase ) pLits[0] = lit_neg( pLits[0] );
if ( Aig_Regular(pNodeT)->fPhase ) pLits[1] = lit_neg( pLits[1] );
if ( pNode->fPhase ) pLits[2] = lit_neg( pLits[2] );
}
RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
assert( RetValue );
pLits[0] = toLitCond(VarI, 0);
pLits[1] = toLitCond(VarE, 1^fCompE);
pLits[2] = toLitCond(VarF, 0);
if ( p->pPars->fPolarFlip )
{
if ( pNodeI->fPhase ) pLits[0] = lit_neg( pLits[0] );
if ( Aig_Regular(pNodeE)->fPhase ) pLits[1] = lit_neg( pLits[1] );
if ( pNode->fPhase ) pLits[2] = lit_neg( pLits[2] );
}
RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
assert( RetValue );
pLits[0] = toLitCond(VarI, 0);
pLits[1] = toLitCond(VarE, 0^fCompE);
pLits[2] = toLitCond(VarF, 1);
if ( p->pPars->fPolarFlip )
{
if ( pNodeI->fPhase ) pLits[0] = lit_neg( pLits[0] );
if ( Aig_Regular(pNodeE)->fPhase ) pLits[1] = lit_neg( pLits[1] );
if ( pNode->fPhase ) pLits[2] = lit_neg( pLits[2] );
}
RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
assert( RetValue );
// two additional clauses
// t' & e' -> f'
// t & e -> f
// t + e + f'
// t' + e' + f
if ( VarT == VarE )
{
// assert( fCompT == !fCompE );
return;
}
pLits[0] = toLitCond(VarT, 0^fCompT);
pLits[1] = toLitCond(VarE, 0^fCompE);
pLits[2] = toLitCond(VarF, 1);
if ( p->pPars->fPolarFlip )
{
if ( Aig_Regular(pNodeT)->fPhase ) pLits[0] = lit_neg( pLits[0] );
if ( Aig_Regular(pNodeE)->fPhase ) pLits[1] = lit_neg( pLits[1] );
if ( pNode->fPhase ) pLits[2] = lit_neg( pLits[2] );
}
RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
assert( RetValue );
pLits[0] = toLitCond(VarT, 1^fCompT);
pLits[1] = toLitCond(VarE, 1^fCompE);
pLits[2] = toLitCond(VarF, 0);
if ( p->pPars->fPolarFlip )
{
if ( Aig_Regular(pNodeT)->fPhase ) pLits[0] = lit_neg( pLits[0] );
if ( Aig_Regular(pNodeE)->fPhase ) pLits[1] = lit_neg( pLits[1] );
if ( pNode->fPhase ) pLits[2] = lit_neg( pLits[2] );
}
RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 3 );
assert( RetValue );
}
/**Function*************************************************************
Synopsis [Addes clauses to the solver.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Dch_AddClausesSuper( Dch_Man_t * p, Aig_Obj_t * pNode, Vec_Ptr_t * vSuper )
{
Aig_Obj_t * pFanin;
int * pLits, nLits, RetValue, i;
assert( !Aig_IsComplement(pNode) );
assert( Aig_ObjIsNode( pNode ) );
// create storage for literals
nLits = Vec_PtrSize(vSuper) + 1;
pLits = ABC_ALLOC( int, nLits );
// suppose AND-gate is A & B = C
// add !A => !C or A + !C
Vec_PtrForEachEntry( Aig_Obj_t *, vSuper, pFanin, i )
{
pLits[0] = toLitCond(Dch_ObjSatNum(p,Aig_Regular(pFanin)), Aig_IsComplement(pFanin));
pLits[1] = toLitCond(Dch_ObjSatNum(p,pNode), 1);
if ( p->pPars->fPolarFlip )
{
if ( Aig_Regular(pFanin)->fPhase ) pLits[0] = lit_neg( pLits[0] );
if ( pNode->fPhase ) pLits[1] = lit_neg( pLits[1] );
}
RetValue = sat_solver_addclause( p->pSat, pLits, pLits + 2 );
assert( RetValue );
}
// add A & B => C or !A + !B + C
Vec_PtrForEachEntry( Aig_Obj_t *, vSuper, pFanin, i )
{
pLits[i] = toLitCond(Dch_ObjSatNum(p,Aig_Regular(pFanin)), !Aig_IsComplement(pFanin));
if ( p->pPars->fPolarFlip )
{
if ( Aig_Regular(pFanin)->fPhase ) pLits[i] = lit_neg( pLits[i] );
}
}
pLits[nLits-1] = toLitCond(Dch_ObjSatNum(p,pNode), 0);
if ( p->pPars->fPolarFlip )
{
if ( pNode->fPhase ) pLits[nLits-1] = lit_neg( pLits[nLits-1] );
}
RetValue = sat_solver_addclause( p->pSat, pLits, pLits + nLits );
assert( RetValue );
ABC_FREE( pLits );
}
/**Function*************************************************************
Synopsis [Collects the supergate.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Dch_CollectSuper_rec( Aig_Obj_t * pObj, Vec_Ptr_t * vSuper, int fFirst, int fUseMuxes )
{
// if the new node is complemented or a PI, another gate begins
if ( Aig_IsComplement(pObj) || Aig_ObjIsCi(pObj) ||
(!fFirst && Aig_ObjRefs(pObj) > 1) ||
(fUseMuxes && Aig_ObjIsMuxType(pObj)) )
{
Vec_PtrPushUnique( vSuper, pObj );
return;
}
// go through the branches
Dch_CollectSuper_rec( Aig_ObjChild0(pObj), vSuper, 0, fUseMuxes );
Dch_CollectSuper_rec( Aig_ObjChild1(pObj), vSuper, 0, fUseMuxes );
}
/**Function*************************************************************
Synopsis [Collects the supergate.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Dch_CollectSuper( Aig_Obj_t * pObj, int fUseMuxes, Vec_Ptr_t * vSuper )
{
assert( !Aig_IsComplement(pObj) );
assert( !Aig_ObjIsCi(pObj) );
Vec_PtrClear( vSuper );
Dch_CollectSuper_rec( pObj, vSuper, 1, fUseMuxes );
}
/**Function*************************************************************
Synopsis [Updates the solver clause database.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Dch_ObjAddToFrontier( Dch_Man_t * p, Aig_Obj_t * pObj, Vec_Ptr_t * vFrontier )
{
assert( !Aig_IsComplement(pObj) );
if ( Dch_ObjSatNum(p,pObj) )
return;
assert( Dch_ObjSatNum(p,pObj) == 0 );
if ( Aig_ObjIsConst1(pObj) )
return;
Vec_PtrPush( p->vUsedNodes, pObj );
Dch_ObjSetSatNum( p, pObj, p->nSatVars++ );
if ( Aig_ObjIsNode(pObj) )
Vec_PtrPush( vFrontier, pObj );
}
/**Function*************************************************************
Synopsis [Updates the solver clause database.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Dch_CnfNodeAddToSolver( Dch_Man_t * p, Aig_Obj_t * pObj )
{
Vec_Ptr_t * vFrontier;
Aig_Obj_t * pNode, * pFanin;
int i, k, fUseMuxes = 1;
// quit if CNF is ready
if ( Dch_ObjSatNum(p,pObj) )
return;
// start the frontier
vFrontier = Vec_PtrAlloc( 100 );
Dch_ObjAddToFrontier( p, pObj, vFrontier );
// explore nodes in the frontier
Vec_PtrForEachEntry( Aig_Obj_t *, vFrontier, pNode, i )
{
// create the supergate
assert( Dch_ObjSatNum(p,pNode) );
if ( fUseMuxes && Aig_ObjIsMuxType(pNode) )
{
Vec_PtrClear( p->vFanins );
Vec_PtrPushUnique( p->vFanins, Aig_ObjFanin0( Aig_ObjFanin0(pNode) ) );
Vec_PtrPushUnique( p->vFanins, Aig_ObjFanin0( Aig_ObjFanin1(pNode) ) );
Vec_PtrPushUnique( p->vFanins, Aig_ObjFanin1( Aig_ObjFanin0(pNode) ) );
Vec_PtrPushUnique( p->vFanins, Aig_ObjFanin1( Aig_ObjFanin1(pNode) ) );
Vec_PtrForEachEntry( Aig_Obj_t *, p->vFanins, pFanin, k )
Dch_ObjAddToFrontier( p, Aig_Regular(pFanin), vFrontier );
Dch_AddClausesMux( p, pNode );
}
else
{
Dch_CollectSuper( pNode, fUseMuxes, p->vFanins );
Vec_PtrForEachEntry( Aig_Obj_t *, p->vFanins, pFanin, k )
Dch_ObjAddToFrontier( p, Aig_Regular(pFanin), vFrontier );
Dch_AddClausesSuper( p, pNode, p->vFanins );
}
assert( Vec_PtrSize(p->vFanins) > 1 );
}
Vec_PtrFree( vFrontier );
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END