cuddzddsetop.c

主要进行大规模的电路综合

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

  FileName    [cuddZddSetop.c]

  PackageName [cudd]

  Synopsis    [Set operations on ZDDs.]

  Description [External procedures included in this module:
		    <ul>
		    <li> Cudd_zddIte()
		    <li> Cudd_zddUnion()
		    <li> Cudd_zddIntersect()
		    <li> Cudd_zddDiff()
		    <li> Cudd_zddDiffConst()
		    <li> Cudd_zddSubset1()
		    <li> Cudd_zddSubset0()
		    <li> Cudd_zddChange()
		    </ul>
	       Internal procedures included in this module:
		    <ul>
		    <li> cuddZddIte()
		    <li> cuddZddUnion()
		    <li> cuddZddIntersect()
		    <li> cuddZddDiff()
		    <li> cuddZddChangeAux()
		    <li> cuddZddSubset1()
		    <li> cuddZddSubset0()
		    </ul>
	       Static procedures included in this module:
		    <ul>
		    <li> zdd_subset1_aux()
		    <li> zdd_subset0_aux()
		    <li> zddVarToConst()
		    </ul>
	      ]

  SeeAlso     []

  Author      [Hyong-Kyoon Shin, In-Ho Moon]

  Copyright [ This file was created at the University of Colorado at
  Boulder.  The University of Colorado at Boulder makes no warranty
  about the suitability of this software for any purpose.  It is
  presented on an AS IS basis.]

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

#include    "util.h"
#include    "cuddInt.h"

/*---------------------------------------------------------------------------*/
/* Constant declarations                                                     */
/*---------------------------------------------------------------------------*/


/*---------------------------------------------------------------------------*/
/* Stucture declarations                                                     */
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/*---------------------------------------------------------------------------*/
/* Type declarations                                                         */
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/*---------------------------------------------------------------------------*/
/* Variable declarations                                                     */
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#ifndef lint
static char rcsid[] DD_UNUSED = "$Id: cuddZddSetop.c,v 1.1.1.1 2003/02/24 22:23:54 wjiang Exp $";
#endif

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/* Macro declarations                                                        */
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/**AutomaticStart*************************************************************/

/*---------------------------------------------------------------------------*/
/* Static function prototypes                                                */
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static DdNode * zdd_subset1_aux ARGS((DdManager *zdd, DdNode *P, DdNode *zvar));
static DdNode * zdd_subset0_aux ARGS((DdManager *zdd, DdNode *P, DdNode *zvar));
static void zddVarToConst ARGS((DdNode *f, DdNode **gp, DdNode **hp, DdNode *base, DdNode *empty));

/**AutomaticEnd***************************************************************/


/*---------------------------------------------------------------------------*/
/* Definition of exported functions                                          */
/*---------------------------------------------------------------------------*/


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

  Synopsis [Computes the ITE of three ZDDs.]

  Description [Computes the ITE of three ZDDs. Returns a pointer to the
  result if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
DdNode *
Cudd_zddIte(
  DdManager * dd,
  DdNode * f,
  DdNode * g,
  DdNode * h)
{
    DdNode *res;

    do {
	dd->reordered = 0;
	res = cuddZddIte(dd, f, g, h);
    } while (dd->reordered == 1);
    return(res);

} /* end of Cudd_zddIte */


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

  Synopsis [Computes the union of two ZDDs.]

  Description [Computes the union of two ZDDs. Returns a pointer to the
  result if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
DdNode *
Cudd_zddUnion(
  DdManager * dd,
  DdNode * P,
  DdNode * Q)
{
    DdNode *res;

    do {
	dd->reordered = 0;
	res = cuddZddUnion(dd, P, Q);
    } while (dd->reordered == 1);
    return(res);

} /* end of Cudd_zddUnion */


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

  Synopsis [Computes the intersection of two ZDDs.]

  Description [Computes the intersection of two ZDDs. Returns a pointer to
  the result if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
DdNode *
Cudd_zddIntersect(
  DdManager * dd,
  DdNode * P,
  DdNode * Q)
{
    DdNode *res;

    do {
	dd->reordered = 0;
	res = cuddZddIntersect(dd, P, Q);
    } while (dd->reordered == 1);
    return(res);

} /* end of Cudd_zddIntersect */


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

  Synopsis [Computes the difference of two ZDDs.]

  Description [Computes the difference of two ZDDs. Returns a pointer to the
  result if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     [Cudd_zddDiffConst]

******************************************************************************/
DdNode *
Cudd_zddDiff(
  DdManager * dd,
  DdNode * P,
  DdNode * Q)
{
    DdNode *res;

    do {
	dd->reordered = 0;
	res = cuddZddDiff(dd, P, Q);
    } while (dd->reordered == 1);
    return(res);

} /* end of Cudd_zddDiff */


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

  Synopsis [Performs the inclusion test for ZDDs (P implies Q).]

  Description [Inclusion test for ZDDs (P implies Q). No new nodes are
  generated by this procedure. Returns empty if true;
  a valid pointer different from empty or DD_NON_CONSTANT otherwise.]

  SideEffects [None]

  SeeAlso     [Cudd_zddDiff]

******************************************************************************/
DdNode *
Cudd_zddDiffConst(
  DdManager * zdd,
  DdNode * P,
  DdNode * Q)
{
    int		p_top, q_top;
    DdNode	*empty = DD_ZERO(zdd), *t, *res;
    DdManager	*table = zdd;

    statLine(zdd);
    if (P == empty)
	return(empty);
    if (Q == empty)
	return(P);
    if (P == Q)
	return(empty);

    /* Check cache.  The cache is shared by cuddZddDiff(). */
    res = cuddCacheLookup2Zdd(table, cuddZddDiff, P, Q);
    if (res != NULL)
	return(res);

    if (cuddIsConstant(P))
	p_top = P->index;
    else
	p_top = zdd->permZ[P->index];
    if (cuddIsConstant(Q))
	q_top = Q->index;
    else
	q_top = zdd->permZ[Q->index];
    if (p_top < q_top) {
	res = DD_NON_CONSTANT;
    } else if (p_top > q_top) {
	res = Cudd_zddDiffConst(zdd, P, cuddE(Q));
    } else {
	t = Cudd_zddDiffConst(zdd, cuddT(P), cuddT(Q));
	if (t != empty)
	    res = DD_NON_CONSTANT;
	else
	    res = Cudd_zddDiffConst(zdd, cuddE(P), cuddE(Q));
    }

    cuddCacheInsert2(table, cuddZddDiff, P, Q, res);

    return(res);

} /* end of Cudd_zddDiffConst */


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

  Synopsis [Computes the positive cofactor of a ZDD w.r.t. a variable.]

  Description [Computes the positive cofactor of a ZDD w.r.t. a
  variable. In terms of combinations, the result is the set of all
  combinations in which the variable is asserted. Returns a pointer to
  the result if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     [Cudd_zddSubset0]

******************************************************************************/
DdNode *
Cudd_zddSubset1(
  DdManager * dd,
  DdNode * P,
  int  var)
{
    DdNode	*r;

    do {
	dd->reordered = 0;
	r = cuddZddSubset1(dd, P, var);
    } while (dd->reordered == 1);

    return(r);

} /* end of Cudd_zddSubset1 */


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

  Synopsis [Computes the negative cofactor of a ZDD w.r.t. a variable.]

  Description [Computes the negative cofactor of a ZDD w.r.t. a
  variable. In terms of combinations, the result is the set of all
  combinations in which the variable is negated. Returns a pointer to
  the result if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     [Cudd_zddSubset1]

******************************************************************************/
DdNode *
Cudd_zddSubset0(
  DdManager * dd,
  DdNode * P,
  int  var)
{
    DdNode	*r;

    do {
	dd->reordered = 0;
	r = cuddZddSubset0(dd, P, var);
    } while (dd->reordered == 1);

    return(r);

} /* end of Cudd_zddSubset0 */


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

  Synopsis [Substitutes a variable with its complement in a ZDD.]

  Description [Substitutes a variable with its complement in a ZDD.
  returns a pointer to the result if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
DdNode *
Cudd_zddChange(
  DdManager * dd,
  DdNode * P,
  int  var)
{
    DdNode	*res;

    if ((unsigned int) var >= CUDD_MAXINDEX - 1) return(NULL);
    
    do {
	dd->reordered = 0;
	res = cuddZddChange(dd, P, var);
    } while (dd->reordered == 1);
    return(res);

} /* end of Cudd_zddChange */


/*---------------------------------------------------------------------------*/
/* Definition of internal functions                                          */
/*---------------------------------------------------------------------------*/


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

  Synopsis    [Performs the recursive step of Cudd_zddIte.]

  Description []

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
DdNode *
cuddZddIte(
  DdManager * dd,
  DdNode * f,
  DdNode * g,
  DdNode * h)
{
    DdNode *tautology, *empty;
    DdNode *r,*Gv,*Gvn,*Hv,*Hvn,*t,*e;
    unsigned int topf,topg,toph,v,top;
    int index;

    statLine(dd);
    /* Trivial cases. */
    /* One variable cases. */
    if (f == (empty = DD_ZERO(dd))) {	/* ITE(0,G,H) = H */
	return(h);
    }
    topf = cuddIZ(dd,f->index);
    topg = cuddIZ(dd,g->index);
    toph = cuddIZ(dd,h->index);
    v = ddMin(topg,toph);
    top  = ddMin(topf,v);

    tautology = (top == CUDD_MAXINDEX) ? DD_ONE(dd) : dd->univ[top];
    if (f == tautology) {			/* ITE(1,G,H) = G */
    	return(g);
    }

    /* From now on, f is known to not be a constant. */
    zddVarToConst(f,&g,&h,tautology,empty);

    /* Check remaining one variable cases. */
    if (g == h) {			/* ITE(F,G,G) = G */
	return(g);
    }

    if (g == tautology) {			/* ITE(F,1,0) = F */
	if (h == empty) return(f);
    }

    /* Check cache. */
    r = cuddCacheLookupZdd(dd,DD_ZDD_ITE_TAG,f,g,h);
    if (r != NULL) {
	return(r);
    }

    /* Recompute these because they may have changed in zddVarToConst. */
    topg = cuddIZ(dd,g->index);
    toph = cuddIZ(dd,h->index);
    v = ddMin(topg,toph);

    if (topf < v) {
	r = cuddZddIte(dd,cuddE(f),g,h);
	if (r == NULL) return(NULL);
    } else if (topf > v) {
	if (topg > v) {
	    Gvn = g;
	    index = h->index;
	} else {
	    Gvn = cuddE(g);
	    index = g->index;
	}
	if (toph > v) {
	    Hv = empty; Hvn = h;
	} else {
	    Hv = cuddT(h); Hvn = cuddE(h);
	}
	e = cuddZddIte(dd,f,Gvn,Hvn);
	if (e == NULL) return(NULL);
	cuddRef(e);
	r = cuddZddGetNode(dd,index,Hv,e);
	if (r == NULL) {
	    Cudd_RecursiveDerefZdd(dd,e);
	    return(NULL);
	}
	cuddDeref(e);
    } else {
	index = f->index;
	if (topg > v) {
	    Gv = empty; Gvn = g;
	} else {
	    Gv = cuddT(g); Gvn = cuddE(g);
	}
	if (toph > v) {
	    Hv = empty; Hvn = h;
	} else {
	    Hv = cuddT(h); Hvn = cuddE(h);
	}
	e = cuddZddIte(dd,cuddE(f),Gvn,Hvn);
	if (e == NULL) return(NULL);
	cuddRef(e);
	t = cuddZddIte(dd,cuddT(f),Gv,Hv);
	if (t == NULL) {
	    Cudd_RecursiveDerefZdd(dd,e);
	    return(NULL);
	}
	cuddRef(t);
	r = cuddZddGetNode(dd,index,t,e);
	if (r == NULL) {
	    Cudd_RecursiveDerefZdd(dd,e);
	    Cudd_RecursiveDerefZdd(dd,t);
	    return(NULL);
	}
	cuddDeref(t);
	cuddDeref(e);
    }

    cuddCacheInsert(dd,DD_ZDD_ITE_TAG,f,g,h,r);

    return(r);

} /* end of cuddZddIte */


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

  Synopsis [Performs the recursive step of Cudd_zddUnion.]

  Description []

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
DdNode *
cuddZddUnion(
  DdManager * zdd,
  DdNode * P,
  DdNode * Q)
{
    int		p_top, q_top;
    DdNode	*empty = DD_ZERO(zdd), *t, *e, *res;
    DdManager	*table = zdd;

    statLine(zdd);
    if (P == empty)
	return(Q);
    if (Q == empty)
	return(P);
    if (P == Q)
	return(P);

    /* Check cache */
    res = cuddCacheLookup2Zdd(table, cuddZddUnion, P, Q);
    if (res != NULL)
	return(res);

    if (cuddIsConstant(P))
	p_top = P->index;
    else
	p_top = zdd->permZ[P->index];
    if (cuddIsConstant(Q))
	q_top = Q->index;
    else
	q_top = zdd->permZ[Q->index];
    if (p_top < q_top) {
	e = cuddZddUnion(zdd, cuddE(P), Q);
	if (e == NULL) return (NULL);
	cuddRef(e);
	res = cuddZddGetNode(zdd, P->index, cuddT(P), e);
	if (res == NULL) {
	    Cudd_RecursiveDerefZdd(table, e);
	    return(NULL);
	}
	cuddDeref(e);
    } else if (p_top > q_top) {
	e = cuddZddUnion(zdd, P, cuddE(Q));
	if (e == NULL) return(NULL);
	cuddRef(e);
	res = cuddZddGetNode(zdd, Q->index, cuddT(Q), e);
	if (res == NULL) {
	    Cudd_RecursiveDerefZdd(table, e);
	    return(NULL);
	}
	cuddDeref(e);
    } else {
	t = cuddZddUnion(zdd, cuddT(P), cuddT(Q));
	if (t == NULL) return(NULL);
	cuddRef(t);