cuddbddite.c

主要进行大规模的电路综合

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

  FileName    [cuddBddIte.c]

  PackageName [cudd]

  Synopsis    [BDD ITE function and satellites.]

  Description [External procedures included in this module:
		<ul>
                <li> Cudd_bddIte()
       	        <li> Cudd_bddIteConstant()
		<li> Cudd_bddIntersect()
		<li> Cudd_bddAnd()
		<li> Cudd_bddOr()
		<li> Cudd_bddNand()
		<li> Cudd_bddNor()
		<li> Cudd_bddXor()
		<li> Cudd_bddXnor()
		<li> Cudd_bddLeq()
		</ul>
       Internal procedures included in this module:
		<ul>
		<li> cuddBddIteRecur()
		<li> cuddBddIntersectRecur()
		<li> cuddBddAndRecur()
		<li> cuddBddXorRecur()
		</ul>
       Static procedures included in this module:
		<ul>
       	        <li> bddVarToConst()
       	        <li> bddVarToCanonical()
       	        <li> bddVarToCanonicalSimple()
		</ul>]

  SeeAlso     []

  Author      [Fabio Somenzi]

  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                                                     */
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/*---------------------------------------------------------------------------*/
/* 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: cuddBddIte.c,v 1.1.1.1 2003/02/24 22:23:51 wjiang Exp $";
#endif

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/* Macro declarations                                                        */
/*---------------------------------------------------------------------------*/


/**AutomaticStart*************************************************************/

/*---------------------------------------------------------------------------*/
/* Static function prototypes                                                */
/*---------------------------------------------------------------------------*/

static void bddVarToConst ARGS((DdNode *f, DdNode **gp, DdNode **hp, DdNode *one));
static int bddVarToCanonical ARGS((DdManager *dd, DdNode **fp, DdNode **gp, DdNode **hp, unsigned int *topfp, unsigned int *topgp, unsigned int *tophp));
static int bddVarToCanonicalSimple ARGS((DdManager *dd, DdNode **fp, DdNode **gp, DdNode **hp, unsigned int *topfp, unsigned int *topgp, unsigned int *tophp));

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


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


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

  Synopsis    [Implements ITE(f,g,h).]

  Description [Implements ITE(f,g,h). Returns a pointer to the
  resulting BDD if successful; NULL if the intermediate result blows
  up.]

  SideEffects [None]

  SeeAlso     [Cudd_addIte Cudd_bddIteConstant Cudd_bddIntersect]

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

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

} /* end of Cudd_bddIte */


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

  Synopsis    [Implements ITEconstant(f,g,h).]

  Description [Implements ITEconstant(f,g,h). Returns a pointer to the
  resulting BDD (which may or may not be constant) or DD_NON_CONSTANT.
  No new nodes are created.]

  SideEffects [None]

  SeeAlso     [Cudd_bddIte Cudd_bddIntersect Cudd_bddLeq Cudd_addIteConstant]

******************************************************************************/
DdNode *
Cudd_bddIteConstant(
  DdManager * dd,
  DdNode * f,
  DdNode * g,
  DdNode * h)
{
    DdNode	 *r, *Fv, *Fnv, *Gv, *Gnv, *H, *Hv, *Hnv, *t, *e;
    DdNode	 *one = DD_ONE(dd);
    DdNode	 *zero = Cudd_Not(one);
    int		 comple;
    unsigned int topf, topg, toph, v;

    statLine(dd);
    /* Trivial cases. */
    if (f == one) 			/* ITE(1,G,H) => G */
	return(g);
    
    if (f == zero)			/* ITE(0,G,H) => H */
	return(h);
    
    /* f now not a constant. */
    bddVarToConst(f, &g, &h, one);	/* possibly convert g or h */
					/* to constants */

    if (g == h) 			/* ITE(F,G,G) => G */
	return(g);

    if (Cudd_IsConstant(g) && Cudd_IsConstant(h)) 
	return(DD_NON_CONSTANT);	/* ITE(F,1,0) or ITE(F,0,1) */
					/* => DD_NON_CONSTANT */
    
    if (g == Cudd_Not(h))
	return(DD_NON_CONSTANT);	/* ITE(F,G,G') => DD_NON_CONSTANT */
					/* if F != G and F != G' */
    
    comple = bddVarToCanonical(dd, &f, &g, &h, &topf, &topg, &toph);

    /* Cache lookup. */
    r = cuddConstantLookup(dd, DD_BDD_ITE_CONSTANT_TAG, f, g, h);
    if (r != NULL) {
	return(Cudd_NotCond(r,comple && r != DD_NON_CONSTANT));
    }

    v = ddMin(topg, toph);

    /* ITE(F,G,H) = (v,G,H) (non constant) if F = (v,1,0), v < top(G,H). */
    if (topf < v && cuddT(f) == one && cuddE(f) == zero) {
	return(DD_NON_CONSTANT);
    }

    /* Compute cofactors. */
    if (topf <= v) {
	v = ddMin(topf, v);		/* v = top_var(F,G,H) */
	Fv = cuddT(f); Fnv = cuddE(f);
    } else {
	Fv = Fnv = f;
    }

    if (topg == v) {
	Gv = cuddT(g); Gnv = cuddE(g);
    } else {
	Gv = Gnv = g;
    }

    if (toph == v) {
	H = Cudd_Regular(h);
	Hv = cuddT(H); Hnv = cuddE(H);
	if (Cudd_IsComplement(h)) {
	    Hv = Cudd_Not(Hv);
	    Hnv = Cudd_Not(Hnv);
	}
    } else {
	Hv = Hnv = h;
    }

    /* Recursion. */
    t = Cudd_bddIteConstant(dd, Fv, Gv, Hv);
    if (t == DD_NON_CONSTANT || !Cudd_IsConstant(t)) {
	cuddCacheInsert(dd, DD_BDD_ITE_CONSTANT_TAG, f, g, h, DD_NON_CONSTANT);
	return(DD_NON_CONSTANT);
    }
    e = Cudd_bddIteConstant(dd, Fnv, Gnv, Hnv);
    if (e == DD_NON_CONSTANT || !Cudd_IsConstant(e) || t != e) {
	cuddCacheInsert(dd, DD_BDD_ITE_CONSTANT_TAG, f, g, h, DD_NON_CONSTANT);
	return(DD_NON_CONSTANT);
    }
    cuddCacheInsert(dd, DD_BDD_ITE_CONSTANT_TAG, f, g, h, t);
    return(Cudd_NotCond(t,comple));

} /* end of Cudd_bddIteConstant */


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

  Synopsis    [Returns a function included in the intersection of f and g.]

  Description [Computes a function included in the intersection of f and
  g. (That is, a witness that the intersection is not empty.)
  Cudd_bddIntersect tries to build as few new nodes as possible. If the
  only result of interest is whether f and g intersect,
  Cudd_bddLeq should be used instead.]

  SideEffects [None]

  SeeAlso     [Cudd_bddLeq Cudd_bddIteConstant]

******************************************************************************/
DdNode *
Cudd_bddIntersect(
  DdManager * dd /* manager */,
  DdNode * f /* first operand */,
  DdNode * g /* second operand */)
{
    DdNode *res;

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

    return(res);

} /* end of Cudd_bddIntersect */


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

  Synopsis    [Computes the conjunction of two BDDs f and g.]

  Description [Computes the conjunction of two BDDs f and g. Returns a
  pointer to the resulting BDD if successful; NULL if the intermediate
  result blows up.]

  SideEffects [None]

  SeeAlso     [Cudd_bddIte Cudd_addApply Cudd_bddAndAbstract Cudd_bddIntersect
  Cudd_bddOr Cudd_bddNand Cudd_bddNor Cudd_bddXor Cudd_bddXnor]

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

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

} /* end of Cudd_bddAnd */


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

  Synopsis    [Computes the disjunction of two BDDs f and g.]

  Description [Computes the disjunction of two BDDs f and g. Returns a
  pointer to the resulting BDD if successful; NULL if the intermediate
  result blows up.]

  SideEffects [None]

  SeeAlso     [Cudd_bddIte Cudd_addApply Cudd_bddAnd Cudd_bddNand Cudd_bddNor
  Cudd_bddXor Cudd_bddXnor]

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

    do {
	dd->reordered = 0;
	res = cuddBddAndRecur(dd,Cudd_Not(f),Cudd_Not(g));
    } while (dd->reordered == 1);
    res = Cudd_NotCond(res,res != NULL);
    return(res);

} /* end of Cudd_bddOr */


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

  Synopsis    [Computes the NAND of two BDDs f and g.]

  Description [Computes the NAND of two BDDs f and g. Returns a
  pointer to the resulting BDD if successful; NULL if the intermediate
  result blows up.]

  SideEffects [None]

  SeeAlso     [Cudd_bddIte Cudd_addApply Cudd_bddAnd Cudd_bddOr Cudd_bddNor
  Cudd_bddXor Cudd_bddXnor]

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

    do {
	dd->reordered = 0;
	res = cuddBddAndRecur(dd,f,g);
    } while (dd->reordered == 1);
    res = Cudd_NotCond(res,res != NULL);
    return(res);

} /* end of Cudd_bddNand */


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

  Synopsis    [Computes the NOR of two BDDs f and g.]

  Description [Computes the NOR of two BDDs f and g. Returns a
  pointer to the resulting BDD if successful; NULL if the intermediate
  result blows up.]

  SideEffects [None]

  SeeAlso     [Cudd_bddIte Cudd_addApply Cudd_bddAnd Cudd_bddOr Cudd_bddNand
  Cudd_bddXor Cudd_bddXnor]

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

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

} /* end of Cudd_bddNor */


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

  Synopsis    [Computes the exclusive OR of two BDDs f and g.]

  Description [Computes the exclusive OR of two BDDs f and g. Returns a
  pointer to the resulting BDD if successful; NULL if the intermediate
  result blows up.]

  SideEffects [None]

  SeeAlso     [Cudd_bddIte Cudd_addApply Cudd_bddAnd Cudd_bddOr
  Cudd_bddNand Cudd_bddNor Cudd_bddXnor]

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

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