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620 lines
15 KiB
620 lines
15 KiB
/**
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@file
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@ingroup cudd
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@brief %ADD ITE function and satellites.
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@author Fabio Somenzi
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@copyright@parblock
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Copyright (c) 1995-2015, Regents of the University of Colorado
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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Neither the name of the University of Colorado nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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@endparblock
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*/
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#include "util.h"
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#include "cuddInt.h"
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/*---------------------------------------------------------------------------*/
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/* Constant declarations */
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/*---------------------------------------------------------------------------*/
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/*---------------------------------------------------------------------------*/
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/* Stucture declarations */
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/*---------------------------------------------------------------------------*/
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/*---------------------------------------------------------------------------*/
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/* Type declarations */
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/*---------------------------------------------------------------------------*/
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/*---------------------------------------------------------------------------*/
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/* Variable declarations */
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/*---------------------------------------------------------------------------*/
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/*---------------------------------------------------------------------------*/
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/* Macro declarations */
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/*---------------------------------------------------------------------------*/
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/** \cond */
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/*---------------------------------------------------------------------------*/
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/* Static function prototypes */
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/*---------------------------------------------------------------------------*/
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static void addVarToConst (DdNode *f, DdNode **gp, DdNode **hp, DdNode *one, DdNode *zero);
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/** \endcond */
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/*---------------------------------------------------------------------------*/
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/* Definition of exported functions */
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/*---------------------------------------------------------------------------*/
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/**
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@brief Implements ITE(f,g,h).
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@details This procedure assumes that f is a 0-1 %ADD.
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@return a pointer to the resulting %ADD if successful; NULL
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otherwise.
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@sideeffect None
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@see Cudd_bddIte Cudd_addIteConstant Cudd_addApply
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*/
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DdNode *
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Cudd_addIte(
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DdManager * dd,
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DdNode * f,
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DdNode * g,
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DdNode * h)
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{
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DdNode *res;
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do {
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dd->reordered = 0;
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res = cuddAddIteRecur(dd,f,g,h);
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} while (dd->reordered == 1);
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if (dd->errorCode == CUDD_TIMEOUT_EXPIRED && dd->timeoutHandler) {
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dd->timeoutHandler(dd, dd->tohArg);
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}
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return(res);
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} /* end of Cudd_addIte */
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/**
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@brief Implements ITEconstant for %ADDs.
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@details f must be a 0-1 %ADD. No new nodes are created. This
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function can be used, for instance, to check that g has a constant
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value (specified by h) whenever f is 1. If the constant value is
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unknown, then one should use Cudd_addEvalConst.
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@return a pointer to the resulting %ADD (which may or may not be
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constant) or DD_NON_CONSTANT.
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@sideeffect None
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@see Cudd_addIte Cudd_addEvalConst Cudd_bddIteConstant
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*/
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DdNode *
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Cudd_addIteConstant(
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DdManager * dd,
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DdNode * f,
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DdNode * g,
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DdNode * h)
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{
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DdNode *one,*zero;
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DdNode *Fv,*Fnv,*Gv,*Gnv,*Hv,*Hnv,*r,*t,*e;
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int topf,topg,toph,v;
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statLine(dd);
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/* Trivial cases. */
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if (f == (one = DD_ONE(dd))) { /* ITE(1,G,H) = G */
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return(g);
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}
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if (f == (zero = DD_ZERO(dd))) { /* ITE(0,G,H) = H */
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return(h);
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}
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/* From now on, f is known not to be a constant. */
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addVarToConst(f,&g,&h,one,zero);
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/* Check remaining one variable cases. */
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if (g == h) { /* ITE(F,G,G) = G */
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return(g);
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}
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if (cuddIsConstant(g) && cuddIsConstant(h)) {
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return(DD_NON_CONSTANT);
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}
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topf = cuddI(dd,f->index);
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topg = cuddI(dd,g->index);
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toph = cuddI(dd,h->index);
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v = ddMin(topg,toph);
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/* ITE(F,G,H) = (x,G,H) (non constant) if F = (x,1,0), x < top(G,H). */
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if (topf < v && cuddIsConstant(cuddT(f)) && cuddIsConstant(cuddE(f))) {
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return(DD_NON_CONSTANT);
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}
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/* Check cache. */
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r = cuddConstantLookup(dd,DD_ADD_ITE_CONSTANT_TAG,f,g,h);
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if (r != NULL) {
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return(r);
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}
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/* Compute cofactors. */
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if (topf <= v) {
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v = ddMin(topf,v); /* v = top_var(F,G,H) */
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Fv = cuddT(f); Fnv = cuddE(f);
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} else {
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Fv = Fnv = f;
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}
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if (topg == v) {
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Gv = cuddT(g); Gnv = cuddE(g);
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} else {
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Gv = Gnv = g;
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}
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if (toph == v) {
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Hv = cuddT(h); Hnv = cuddE(h);
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} else {
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Hv = Hnv = h;
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}
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/* Recursive step. */
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t = Cudd_addIteConstant(dd,Fv,Gv,Hv);
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if (t == DD_NON_CONSTANT || !cuddIsConstant(t)) {
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cuddCacheInsert(dd, DD_ADD_ITE_CONSTANT_TAG, f, g, h, DD_NON_CONSTANT);
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return(DD_NON_CONSTANT);
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}
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e = Cudd_addIteConstant(dd,Fnv,Gnv,Hnv);
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if (e == DD_NON_CONSTANT || !cuddIsConstant(e) || t != e) {
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cuddCacheInsert(dd, DD_ADD_ITE_CONSTANT_TAG, f, g, h, DD_NON_CONSTANT);
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return(DD_NON_CONSTANT);
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}
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cuddCacheInsert(dd, DD_ADD_ITE_CONSTANT_TAG, f, g, h, t);
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return(t);
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} /* end of Cudd_addIteConstant */
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/**
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@brief Checks whether %ADD g is constant whenever %ADD f is 1.
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@details f must be a 0-1 %ADD. If f is identically 0, the check is
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assumed to be successful, and the background value is returned. No
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new nodes are created.
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@return a pointer to the resulting %ADD (which may or may not be
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constant) or DD_NON_CONSTANT.
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@sideeffect None
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@see Cudd_addIteConstant Cudd_addLeq
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*/
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DdNode *
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Cudd_addEvalConst(
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DdManager * dd,
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DdNode * f,
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DdNode * g)
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{
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DdNode *zero;
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DdNode *Fv,*Fnv,*Gv,*Gnv,*r,*t,*e;
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int topf,topg;
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#ifdef DD_DEBUG
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assert(!Cudd_IsComplement(f));
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#endif
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statLine(dd);
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/* Terminal cases. */
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if (f == DD_ONE(dd) || cuddIsConstant(g)) {
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return(g);
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}
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if (f == (zero = DD_ZERO(dd))) {
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return(dd->background);
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}
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#ifdef DD_DEBUG
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assert(!cuddIsConstant(f));
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#endif
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/* From now on, f and g are known not to be constants. */
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topf = cuddI(dd,f->index);
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topg = cuddI(dd,g->index);
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/* Check cache. */
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r = cuddConstantLookup(dd,DD_ADD_EVAL_CONST_TAG,f,g,g);
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if (r != NULL) {
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return(r);
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}
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/* Compute cofactors. */
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if (topf <= topg) {
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Fv = cuddT(f); Fnv = cuddE(f);
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} else {
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Fv = Fnv = f;
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}
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if (topg <= topf) {
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Gv = cuddT(g); Gnv = cuddE(g);
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} else {
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Gv = Gnv = g;
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}
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/* Recursive step. */
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if (Fv != zero) {
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t = Cudd_addEvalConst(dd,Fv,Gv);
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if (t == DD_NON_CONSTANT || !cuddIsConstant(t)) {
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cuddCacheInsert2(dd, Cudd_addEvalConst, f, g, DD_NON_CONSTANT);
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return(DD_NON_CONSTANT);
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}
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if (Fnv != zero) {
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e = Cudd_addEvalConst(dd,Fnv,Gnv);
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if (e == DD_NON_CONSTANT || !cuddIsConstant(e) || t != e) {
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cuddCacheInsert2(dd, Cudd_addEvalConst, f, g, DD_NON_CONSTANT);
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return(DD_NON_CONSTANT);
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}
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}
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cuddCacheInsert2(dd,Cudd_addEvalConst,f,g,t);
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return(t);
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} else { /* Fnv must be != zero */
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e = Cudd_addEvalConst(dd,Fnv,Gnv);
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cuddCacheInsert2(dd, Cudd_addEvalConst, f, g, e);
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return(e);
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}
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} /* end of Cudd_addEvalConst */
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/**
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@brief Computes the complement of an %ADD a la C language.
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@details The complement of 0 is 1 and the complement of everything
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else is 0.
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@return a pointer to the resulting %ADD if successful; NULL otherwise.
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@sideeffect None
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@see Cudd_addNegate
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*/
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DdNode *
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Cudd_addCmpl(
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DdManager * dd,
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DdNode * f)
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{
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DdNode *res;
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do {
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dd->reordered = 0;
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res = cuddAddCmplRecur(dd,f);
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} while (dd->reordered == 1);
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if (dd->errorCode == CUDD_TIMEOUT_EXPIRED && dd->timeoutHandler) {
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dd->timeoutHandler(dd, dd->tohArg);
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}
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return(res);
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} /* end of Cudd_addCmpl */
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/**
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@brief Determines whether f is less than or equal to g.
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@details No new nodes are created. This procedure works for arbitrary ADDs.
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For 0-1 ADDs Cudd_addEvalConst is more efficient.
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@return 1 if f is less than or equal to g; 0 otherwise.
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@sideeffect None
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@see Cudd_addIteConstant Cudd_addEvalConst Cudd_bddLeq
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*/
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int
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Cudd_addLeq(
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DdManager * dd,
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DdNode * f,
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DdNode * g)
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{
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DdNode *tmp, *fv, *fvn, *gv, *gvn;
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int topf, topg, res;
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/* Terminal cases. */
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if (f == g) return(1);
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statLine(dd);
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if (cuddIsConstant(f)) {
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if (cuddIsConstant(g)) return(cuddV(f) <= cuddV(g));
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if (f == DD_MINUS_INFINITY(dd)) return(1);
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if (f == DD_PLUS_INFINITY(dd)) return(0); /* since f != g */
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}
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if (g == DD_PLUS_INFINITY(dd)) return(1);
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if (g == DD_MINUS_INFINITY(dd)) return(0); /* since f != g */
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/* Check cache. */
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tmp = cuddCacheLookup2(dd,(DD_CTFP)Cudd_addLeq,f,g);
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if (tmp != NULL) {
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return(tmp == DD_ONE(dd));
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}
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/* Compute cofactors. One of f and g is not constant. */
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topf = cuddI(dd,f->index);
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topg = cuddI(dd,g->index);
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if (topf <= topg) {
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fv = cuddT(f); fvn = cuddE(f);
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} else {
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fv = fvn = f;
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}
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if (topg <= topf) {
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gv = cuddT(g); gvn = cuddE(g);
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} else {
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gv = gvn = g;
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}
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res = Cudd_addLeq(dd,fvn,gvn) && Cudd_addLeq(dd,fv,gv);
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/* Store result in cache and return. */
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cuddCacheInsert2(dd,(DD_CTFP) Cudd_addLeq,f,g,
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Cudd_NotCond(DD_ONE(dd),res==0));
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return(res);
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} /* end of Cudd_addLeq */
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/*---------------------------------------------------------------------------*/
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/* Definition of internal functions */
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/*---------------------------------------------------------------------------*/
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/**
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@brief Implements the recursive step of Cudd_addIte(f,g,h).
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@return a pointer to the resulting %ADD if successful; NULL
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otherwise.
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@sideeffect None
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@see Cudd_addIte
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*/
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DdNode *
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cuddAddIteRecur(
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DdManager * dd,
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DdNode * f,
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DdNode * g,
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DdNode * h)
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{
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DdNode *one,*zero;
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DdNode *r,*Fv,*Fnv,*Gv,*Gnv,*Hv,*Hnv,*t,*e;
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int topf,topg,toph,v;
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unsigned int index;
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statLine(dd);
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/* Trivial cases. */
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/* One variable cases. */
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if (f == (one = DD_ONE(dd))) { /* ITE(1,G,H) = G */
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return(g);
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}
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if (f == (zero = DD_ZERO(dd))) { /* ITE(0,G,H) = H */
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return(h);
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}
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/* From now on, f is known to not be a constant. */
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addVarToConst(f,&g,&h,one,zero);
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/* Check remaining one variable cases. */
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if (g == h) { /* ITE(F,G,G) = G */
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return(g);
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}
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if (g == one) { /* ITE(F,1,0) = F */
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if (h == zero) return(f);
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}
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topf = cuddI(dd,f->index);
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topg = cuddI(dd,g->index);
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toph = cuddI(dd,h->index);
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v = ddMin(topg,toph);
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/* A shortcut: ITE(F,G,H) = (x,G,H) if F=(x,1,0), x < top(G,H). */
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if (topf < v && cuddT(f) == one && cuddE(f) == zero) {
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r = cuddUniqueInter(dd,(int)f->index,g,h);
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return(r);
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}
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if (topf < v && cuddT(f) == zero && cuddE(f) == one) {
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r = cuddUniqueInter(dd,(int)f->index,h,g);
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return(r);
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}
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/* Check cache. */
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r = cuddCacheLookup(dd,DD_ADD_ITE_TAG,f,g,h);
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if (r != NULL) {
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return(r);
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}
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checkWhetherToGiveUp(dd);
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/* Compute cofactors. */
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index = f->index;
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if (topf <= v) {
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v = ddMin(topf,v); /* v = top_var(F,G,H) */
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Fv = cuddT(f); Fnv = cuddE(f);
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} else {
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Fv = Fnv = f;
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}
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if (topg == v) {
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index = g->index;
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Gv = cuddT(g); Gnv = cuddE(g);
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} else {
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Gv = Gnv = g;
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}
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if (toph == v) {
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index = h->index;
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Hv = cuddT(h); Hnv = cuddE(h);
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} else {
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Hv = Hnv = h;
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}
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/* Recursive step. */
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t = cuddAddIteRecur(dd,Fv,Gv,Hv);
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if (t == NULL) return(NULL);
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cuddRef(t);
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e = cuddAddIteRecur(dd,Fnv,Gnv,Hnv);
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if (e == NULL) {
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Cudd_RecursiveDeref(dd,t);
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return(NULL);
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}
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cuddRef(e);
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r = (t == e) ? t : cuddUniqueInter(dd,index,t,e);
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if (r == NULL) {
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Cudd_RecursiveDeref(dd,t);
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Cudd_RecursiveDeref(dd,e);
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return(NULL);
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}
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cuddDeref(t);
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cuddDeref(e);
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cuddCacheInsert(dd,DD_ADD_ITE_TAG,f,g,h,r);
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return(r);
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} /* end of cuddAddIteRecur */
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/**
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@brief Performs the recursive step of Cudd_addCmpl.
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@return a pointer to the resulting %ADD if successful; NULL
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otherwise.
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@sideeffect None
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@see Cudd_addCmpl
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*/
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DdNode *
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cuddAddCmplRecur(
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DdManager * dd,
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DdNode * f)
|
|
{
|
|
DdNode *one,*zero;
|
|
DdNode *r,*Fv,*Fnv,*t,*e;
|
|
|
|
statLine(dd);
|
|
one = DD_ONE(dd);
|
|
zero = DD_ZERO(dd);
|
|
|
|
if (cuddIsConstant(f)) {
|
|
if (f == zero) {
|
|
return(one);
|
|
} else {
|
|
return(zero);
|
|
}
|
|
}
|
|
r = cuddCacheLookup1(dd,Cudd_addCmpl,f);
|
|
if (r != NULL) {
|
|
return(r);
|
|
}
|
|
checkWhetherToGiveUp(dd);
|
|
Fv = cuddT(f);
|
|
Fnv = cuddE(f);
|
|
t = cuddAddCmplRecur(dd,Fv);
|
|
if (t == NULL) return(NULL);
|
|
cuddRef(t);
|
|
e = cuddAddCmplRecur(dd,Fnv);
|
|
if (e == NULL) {
|
|
Cudd_RecursiveDeref(dd,t);
|
|
return(NULL);
|
|
}
|
|
cuddRef(e);
|
|
r = (t == e) ? t : cuddUniqueInter(dd,(int)f->index,t,e);
|
|
if (r == NULL) {
|
|
Cudd_RecursiveDeref(dd, t);
|
|
Cudd_RecursiveDeref(dd, e);
|
|
return(NULL);
|
|
}
|
|
cuddDeref(t);
|
|
cuddDeref(e);
|
|
cuddCacheInsert1(dd,Cudd_addCmpl,f,r);
|
|
return(r);
|
|
|
|
} /* end of cuddAddCmplRecur */
|
|
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
/* Definition of static functions */
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
|
|
/**
|
|
@brief Replaces variables with constants if possible (part of
|
|
canonical form).
|
|
|
|
@sideeffect None
|
|
|
|
*/
|
|
static void
|
|
addVarToConst(
|
|
DdNode * f,
|
|
DdNode ** gp,
|
|
DdNode ** hp,
|
|
DdNode * one,
|
|
DdNode * zero)
|
|
{
|
|
DdNode *g = *gp;
|
|
DdNode *h = *hp;
|
|
|
|
if (f == g) { /* ITE(F,F,H) = ITE(F,1,H) = F + H */
|
|
*gp = one;
|
|
}
|
|
|
|
if (f == h) { /* ITE(F,G,F) = ITE(F,G,0) = F * G */
|
|
*hp = zero;
|
|
}
|
|
|
|
} /* end of addVarToConst */
|