ivyOper.c

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/**CFile****************************************************************

  FileName    [ivyOper.c]

  SystemName  [ABC: Logic synthesis and verification system.]

  PackageName [And-Inverter Graph package.]

  Synopsis    [AIG operations.]

  Author      [Alan Mishchenko]
  
  Affiliation [UC Berkeley]

  Date        [Ver. 1.0. Started - May 11, 2006.]

  Revision    [$Id: ivyOper.c,v 1.00 2006/05/11 00:00:00 alanmi Exp $]

***********************************************************************/

#include "ivy.h"

ABC_NAMESPACE_IMPL_START


////////////////////////////////////////////////////////////////////////
///                        DECLARATIONS                              ///
////////////////////////////////////////////////////////////////////////

// procedure to detect an EXOR gate
static inline int Ivy_ObjIsExorType( Ivy_Obj_t * p0, Ivy_Obj_t * p1, Ivy_Obj_t ** ppFan0, Ivy_Obj_t ** ppFan1 )
{
    if ( !Ivy_IsComplement(p0) || !Ivy_IsComplement(p1) )
        return 0;
    p0 = Ivy_Regular(p0);
    p1 = Ivy_Regular(p1);
    if ( !Ivy_ObjIsAnd(p0) || !Ivy_ObjIsAnd(p1) )
        return 0;
    if ( Ivy_ObjFanin0(p0) != Ivy_ObjFanin0(p1) || Ivy_ObjFanin1(p0) != Ivy_ObjFanin1(p1) )
        return 0;
    if ( Ivy_ObjFaninC0(p0) == Ivy_ObjFaninC0(p1) || Ivy_ObjFaninC1(p0) == Ivy_ObjFaninC1(p1) )
        return 0;
    *ppFan0 = Ivy_ObjChild0(p0);
    *ppFan1 = Ivy_ObjChild1(p0);
    return 1;
}

////////////////////////////////////////////////////////////////////////
///                     FUNCTION DEFINITIONS                         ///
////////////////////////////////////////////////////////////////////////

/**Function*************************************************************

  Synopsis    [Perform one operation.]

  Description [The argument nodes can be complemented.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_Oper( Ivy_Man_t * p, Ivy_Obj_t * p0, Ivy_Obj_t * p1, Ivy_Type_t Type )
{
    if ( Type == IVY_AND )
        return Ivy_And( p, p0, p1 );
    if ( Type == IVY_EXOR )
        return Ivy_Exor( p, p0, p1 );
    assert( 0 );
    return NULL;
}

/**Function*************************************************************

  Synopsis    [Performs canonicization step.]

  Description [The argument nodes can be complemented.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_And( Ivy_Man_t * p, Ivy_Obj_t * p0, Ivy_Obj_t * p1 )
{
//    Ivy_Obj_t * pFan0, * pFan1;
    // check trivial cases
    if ( p0 == p1 )
        return p0;
    if ( p0 == Ivy_Not(p1) )
        return Ivy_Not(p->pConst1);
    if ( Ivy_Regular(p0) == p->pConst1 )
        return p0 == p->pConst1 ? p1 : Ivy_Not(p->pConst1);
    if ( Ivy_Regular(p1) == p->pConst1 )
        return p1 == p->pConst1 ? p0 : Ivy_Not(p->pConst1);
    // check if it can be an EXOR gate
//    if ( Ivy_ObjIsExorType( p0, p1, &pFan0, &pFan1 ) )
//        return Ivy_CanonExor( pFan0, pFan1 );
    return Ivy_CanonAnd( p, p0, p1 );
}

/**Function*************************************************************

  Synopsis    [Performs canonicization step.]

  Description [The argument nodes can be complemented.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_Exor( Ivy_Man_t * p, Ivy_Obj_t * p0, Ivy_Obj_t * p1 )
{
/*
    // check trivial cases
    if ( p0 == p1 )
        return Ivy_Not(p->pConst1);
    if ( p0 == Ivy_Not(p1) )
        return p->pConst1;
    if ( Ivy_Regular(p0) == p->pConst1 )
        return Ivy_NotCond( p1, p0 == p->pConst1 );
    if ( Ivy_Regular(p1) == p->pConst1 )
        return Ivy_NotCond( p0, p1 == p->pConst1 );
    // check the table
    return Ivy_CanonExor( p, p0, p1 );
*/
    return Ivy_Or( p, Ivy_And(p, p0, Ivy_Not(p1)), Ivy_And(p, Ivy_Not(p0), p1) );
}

/**Function*************************************************************

  Synopsis    [Implements Boolean OR.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_Or( Ivy_Man_t * p, Ivy_Obj_t * p0, Ivy_Obj_t * p1 )
{
    return Ivy_Not( Ivy_And( p, Ivy_Not(p0), Ivy_Not(p1) ) );
}

/**Function*************************************************************

  Synopsis    [Implements ITE operation.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_Mux( Ivy_Man_t * p, Ivy_Obj_t * pC, Ivy_Obj_t * p1, Ivy_Obj_t * p0 )
{
    Ivy_Obj_t * pTempA1, * pTempA2, * pTempB1, * pTempB2, * pTemp;
    int Count0, Count1;
    // consider trivial cases
    if ( p0 == Ivy_Not(p1) )
        return Ivy_Exor( p, pC, p0 );
    // other cases can be added
    // implement the first MUX (F = C * x1 + C' * x0)
    pTempA1 = Ivy_TableLookup( p, Ivy_ObjCreateGhost(p, pC,          p1, IVY_AND, IVY_INIT_NONE) );
    pTempA2 = Ivy_TableLookup( p, Ivy_ObjCreateGhost(p, Ivy_Not(pC), p0, IVY_AND, IVY_INIT_NONE) );
    if ( pTempA1 && pTempA2 )
    {
        pTemp = Ivy_TableLookup( p, Ivy_ObjCreateGhost(p, Ivy_Not(pTempA1), Ivy_Not(pTempA2), IVY_AND, IVY_INIT_NONE) );
        if ( pTemp ) return Ivy_Not(pTemp);
    }
    Count0 = (pTempA1 != NULL) + (pTempA2 != NULL);
    // implement the second MUX (F' = C * x1' + C' * x0')
    pTempB1 = Ivy_TableLookup( p, Ivy_ObjCreateGhost(p, pC,          Ivy_Not(p1), IVY_AND, IVY_INIT_NONE) );
    pTempB2 = Ivy_TableLookup( p, Ivy_ObjCreateGhost(p, Ivy_Not(pC), Ivy_Not(p0), IVY_AND, IVY_INIT_NONE) );
    if ( pTempB1 && pTempB2 )
    {
        pTemp = Ivy_TableLookup( p, Ivy_ObjCreateGhost(p, Ivy_Not(pTempB1), Ivy_Not(pTempB2), IVY_AND, IVY_INIT_NONE) );
        if ( pTemp ) return pTemp;
    }
    Count1 = (pTempB1 != NULL) + (pTempB2 != NULL);
    // compare and decide which one to implement
    if ( Count0 >= Count1 )
    {
        pTempA1 = pTempA1? pTempA1 : Ivy_And(p, pC,          p1);
        pTempA2 = pTempA2? pTempA2 : Ivy_And(p, Ivy_Not(pC), p0);
        return Ivy_Or( p, pTempA1, pTempA2 );
    }
    pTempB1 = pTempB1? pTempB1 : Ivy_And(p, pC,          Ivy_Not(p1));
    pTempB2 = pTempB2? pTempB2 : Ivy_And(p, Ivy_Not(pC), Ivy_Not(p0));
    return Ivy_Not( Ivy_Or( p, pTempB1, pTempB2 ) );

//    return Ivy_Or( Ivy_And(pC, p1), Ivy_And(Ivy_Not(pC), p0) );
}

/**Function*************************************************************

  Synopsis    [Implements ITE operation.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_Maj( Ivy_Man_t * p, Ivy_Obj_t * pA, Ivy_Obj_t * pB, Ivy_Obj_t * pC )
{
    return Ivy_Or( p, Ivy_Or(p, Ivy_And(p, pA, pB), Ivy_And(p, pA, pC)), Ivy_And(p, pB, pC) );
}

/**Function*************************************************************

  Synopsis    [Constructs the well-balanced tree of gates.]

  Description [Disregards levels and possible logic sharing.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_Multi_rec( Ivy_Man_t * p, Ivy_Obj_t ** ppObjs, int nObjs, Ivy_Type_t Type )
{
    Ivy_Obj_t * pObj1, * pObj2;
    if ( nObjs == 1 )
        return ppObjs[0];
    pObj1 = Ivy_Multi_rec( p, ppObjs,           nObjs/2,         Type );
    pObj2 = Ivy_Multi_rec( p, ppObjs + nObjs/2, nObjs - nObjs/2, Type );
    return Ivy_Oper( p, pObj1, pObj2, Type );
}

/**Function*************************************************************

  Synopsis    [Old code.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_Multi( Ivy_Man_t * p, Ivy_Obj_t ** pArgs, int nArgs, Ivy_Type_t Type )
{
    assert( Type == IVY_AND || Type == IVY_EXOR );
    assert( nArgs > 0 );
    return Ivy_Multi_rec( p, pArgs, nArgs, Type );
}

/**Function*************************************************************

  Synopsis    [Implements the miter.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_Miter( Ivy_Man_t * p, Vec_Ptr_t * vPairs )
{
    int i;
    assert( vPairs->nSize > 0 );
    assert( vPairs->nSize % 2 == 0 );
    // go through the cubes of the node's SOP
    for ( i = 0; i < vPairs->nSize; i += 2 )
        vPairs->pArray[i/2] = Ivy_Not( Ivy_Exor( p, (Ivy_Obj_t *)vPairs->pArray[i], (Ivy_Obj_t *)vPairs->pArray[i+1] ) );
    vPairs->nSize = vPairs->nSize/2;
    return Ivy_Not( Ivy_Multi_rec( p, (Ivy_Obj_t **)vPairs->pArray, vPairs->nSize, IVY_AND ) );
}
 
/**Function*************************************************************

  Synopsis    [Performs canonicization step.]

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
Ivy_Obj_t * Ivy_Latch( Ivy_Man_t * p, Ivy_Obj_t * pObj, Ivy_Init_t Init )
{
    return Ivy_CanonLatch( p, pObj, Init );
}

////////////////////////////////////////////////////////////////////////
///                       END OF FILE                                ///
////////////////////////////////////////////////////////////////////////


ABC_NAMESPACE_IMPL_END