exorCubes.c

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

  FileName    [exorCubes.c]

  SystemName  [ABC: Logic synthesis and verification system.]

  PackageName [Exclusive sum-of-product minimization.]

  Synopsis    [Cube manipulation.]

  Author      [Alan Mishchenko]
  
  Affiliation [UC Berkeley]

  Date        [Ver. 1.0. Started - June 20, 2005.]

  Revision    [$Id: exorCubes.c,v 1.0 2005/06/20 00:00:00 alanmi Exp $]

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

////////////////////////////////////////////////////////////////////////
///                                                                  ///
///                  Implementation of EXORCISM - 4                  ///
///              An Exclusive Sum-of-Product Minimizer               ///
///                                                                  ///
///               Alan Mishchenko  <alanmi@ee.pdx.edu>               ///
///                                                                  ///
////////////////////////////////////////////////////////////////////////
///                                                                  ///
///              Cube Allocation and Free Cube Management            ///
///                                                                  ///
///  Ver. 1.0. Started - July 18, 2000. Last update - July 20, 2000  ///
///  Ver. 1.1. Started - July 24, 2000. Last update - July 29, 2000  ///
///  Ver. 1.2. Started - July 30, 2000. Last update - July 30, 2000  ///
///  Ver. 1.5. Started -  Aug 19, 2000. Last update -  Aug 19, 2000  ///
///                                                                  ///
////////////////////////////////////////////////////////////////////////
///   This software was tested with the BDD package "CUDD", v.2.3.0  ///
///                          by Fabio Somenzi                        ///
///                  http://vlsi.colorado.edu/~fabio/                ///
////////////////////////////////////////////////////////////////////////

#include "exor.h"

ABC_NAMESPACE_IMPL_START

////////////////////////////////////////////////////////////////////////
///                       EXTERNAL FUNCTIONS                         ///
////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////
///                       EXTERNAL VARIABLES                         ///
////////////////////////////////////////////////////////////////////////

// information about the cube cover before and after simplification
extern cinfo g_CoverInfo;

////////////////////////////////////////////////////////////////////////
///                    FUNCTIONS OF THIS MODULE                      ///
////////////////////////////////////////////////////////////////////////

// cube cover memory allocation/delocation procedures
// (called from the ExorMain module)
int AllocateCover( int nCubes, int nWordsIn, int nWordsOut );
void DelocateCover();

// manipulation of the free cube list
// (called from Pseudo-Kronecker, ExorList, and ExorLink modules)
void AddToFreeCubes( Cube * pC );
Cube * GetFreeCube();

////////////////////////////////////////////////////////////////////////
///                      EXPORTED VARIABLES                          ///
////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////
///                      STATIC VARIABLES                            ///
////////////////////////////////////////////////////////////////////////

// the pointer to the allocated memory
Cube ** s_pCoverMemory;

// the list of free cubes
Cube * s_CubesFree;

///////////////////////////////////////////////////////////////////
///                  CUBE COVER MEMORY MANAGEMENT                //
///////////////////////////////////////////////////////////////////

int AllocateCover( int nCubes, int nWordsIn, int nWordsOut )
// uses the cover parameters nCubes and nWords
// to allocate-and-clean the cover in one large piece
{
    int OneCubeSize;
    int OneInputSetSize;
    Cube ** pp;
    int TotalSize;
    int i, k;

    // determine the size of one cube WITH storage for bits
    OneCubeSize = sizeof(Cube) + (nWordsIn+nWordsOut)*sizeof(unsigned);
    // determine what is the amount of storage for the input part of the cube 
    OneInputSetSize = nWordsIn*sizeof(unsigned);

    // allocate memory for the array of pointers
    pp = (Cube **)ABC_ALLOC( Cube *, nCubes );
    if ( pp == NULL )
        return 0;

    // determine the size of the total cube cover
    TotalSize = nCubes*OneCubeSize;
    // allocate and clear memory for the cover in one large piece
    pp[0] = (Cube *)ABC_ALLOC( char, TotalSize );
    if ( pp[0] == NULL )
        return 0;
    memset( pp[0], 0, TotalSize );

    // assign pointers to cubes and bit strings inside this piece
    pp[0]->pCubeDataIn  = (unsigned*)(pp[0] + 1);
    pp[0]->pCubeDataOut = (unsigned*)((char*)pp[0]->pCubeDataIn + OneInputSetSize);
    for ( i = 1; i < nCubes; i++ )
    {
        pp[i] = (Cube *)((char*)pp[i-1] + OneCubeSize);
        pp[i]->pCubeDataIn = (unsigned*)(pp[i] + 1);
        pp[i]->pCubeDataOut = (unsigned*)((char*)pp[i]->pCubeDataIn + OneInputSetSize);
    }

    // connect the cubes into the list using Next pointers
    for ( k = 0; k < nCubes-1; k++ )
        pp[k]->Next = pp[k+1];
    // the last pointer is already set to NULL

    // assign the head of the free list
    s_CubesFree = pp[0];
    // set the counters of the used and free cubes
    g_CoverInfo.nCubesInUse = 0;
    g_CoverInfo.nCubesFree = nCubes;

    // save the pointer to the allocated memory
    s_pCoverMemory = pp;

    assert ( g_CoverInfo.nCubesInUse + g_CoverInfo.nCubesFree == g_CoverInfo.nCubesAlloc );

    return nCubes*sizeof(Cube *) + TotalSize;
}

void DelocateCover()
{
    ABC_FREE( s_pCoverMemory[0] );
    ABC_FREE( s_pCoverMemory );
}

///////////////////////////////////////////////////////////////////
///           FREE CUBE LIST MANIPULATION FUNCTIONS             ///
///////////////////////////////////////////////////////////////////

void AddToFreeCubes( Cube * p )
{
    assert( p );
    assert( p->Prev == NULL ); // the cube should not be in use
    assert( p->Next == NULL );
    assert( p->ID );

    p->Next = s_CubesFree;
    s_CubesFree = p;

    // set the ID of the cube to 0, 
    // so that cube pair garbage collection could recognize it as different
    p->ID = 0;

    g_CoverInfo.nCubesFree++;
}

Cube * GetFreeCube()
{
    Cube * p;
    assert( s_CubesFree );
    p = s_CubesFree;
    s_CubesFree = s_CubesFree->Next;
    p->Next = NULL;
    g_CoverInfo.nCubesFree--;
    return p;
}

///////////////////////////////////////////////////////////////////
////////////              End of File             /////////////////
///////////////////////////////////////////////////////////////////


ABC_NAMESPACE_IMPL_END