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Diffstat (limited to 'src/bdd/cudd/cuddGenCof.c')
-rw-r--r-- | src/bdd/cudd/cuddGenCof.c | 1968 |
1 files changed, 1968 insertions, 0 deletions
diff --git a/src/bdd/cudd/cuddGenCof.c b/src/bdd/cudd/cuddGenCof.c new file mode 100644 index 00000000..59ae55d7 --- /dev/null +++ b/src/bdd/cudd/cuddGenCof.c @@ -0,0 +1,1968 @@ +/**CFile*********************************************************************** + + FileName [cuddGenCof.c] + + PackageName [cudd] + + Synopsis [Generalized cofactors for BDDs and ADDs.] + + Description [External procedures included in this module: + <ul> + <li> Cudd_bddConstrain() + <li> Cudd_bddRestrict() + <li> Cudd_addConstrain() + <li> Cudd_bddConstrainDecomp() + <li> Cudd_addRestrict() + <li> Cudd_bddCharToVect() + <li> Cudd_bddLICompaction() + <li> Cudd_bddSqueeze() + <li> Cudd_SubsetCompress() + <li> Cudd_SupersetCompress() + </ul> + Internal procedures included in this module: + <ul> + <li> cuddBddConstrainRecur() + <li> cuddBddRestrictRecur() + <li> cuddAddConstrainRecur() + <li> cuddAddRestrictRecur() + <li> cuddBddLICompaction() + </ul> + Static procedures included in this module: + <ul> + <li> cuddBddConstrainDecomp() + <li> cuddBddCharToVect() + <li> cuddBddLICMarkEdges() + <li> cuddBddLICBuildResult() + <li> cuddBddSqueeze() + </ul> + ] + + 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 */ +/*---------------------------------------------------------------------------*/ + +/* Codes for edge markings in Cudd_bddLICompaction. The codes are defined +** so that they can be bitwise ORed to implement the code priority scheme. +*/ +#define DD_LIC_DC 0 +#define DD_LIC_1 1 +#define DD_LIC_0 2 +#define DD_LIC_NL 3 + +/*---------------------------------------------------------------------------*/ +/* Stucture declarations */ +/*---------------------------------------------------------------------------*/ + + +/*---------------------------------------------------------------------------*/ +/* Type declarations */ +/*---------------------------------------------------------------------------*/ + +/* Key for the cache used in the edge marking phase. */ +typedef struct MarkCacheKey { + DdNode *f; + DdNode *c; +} MarkCacheKey; + +/*---------------------------------------------------------------------------*/ +/* Variable declarations */ +/*---------------------------------------------------------------------------*/ + +#ifndef lint +static char rcsid[] DD_UNUSED = "$Id: cuddGenCof.c,v 1.1.1.1 2003/02/24 22:23:52 wjiang Exp $"; +#endif + +/*---------------------------------------------------------------------------*/ +/* Macro declarations */ +/*---------------------------------------------------------------------------*/ + + +/**AutomaticStart*************************************************************/ + +/*---------------------------------------------------------------------------*/ +/* Static function prototypes */ +/*---------------------------------------------------------------------------*/ + +static int cuddBddConstrainDecomp ARGS((DdManager *dd, DdNode *f, DdNode **decomp)); +static DdNode * cuddBddCharToVect ARGS((DdManager *dd, DdNode *f, DdNode *x)); +static int cuddBddLICMarkEdges ARGS((DdManager *dd, DdNode *f, DdNode *c, st_table *table, st_table *cache)); +static DdNode * cuddBddLICBuildResult ARGS((DdManager *dd, DdNode *f, st_table *cache, st_table *table)); +static int MarkCacheHash ARGS((char *ptr, int modulus)); +static int MarkCacheCompare ARGS((const char *ptr1, const char *ptr2)); +static enum st_retval MarkCacheCleanUp ARGS((char *key, char *value, char *arg)); +static DdNode * cuddBddSqueeze ARGS((DdManager *dd, DdNode *l, DdNode *u)); + +/**AutomaticEnd***************************************************************/ + + +/*---------------------------------------------------------------------------*/ +/* Definition of exported functions */ +/*---------------------------------------------------------------------------*/ + + +/**Function******************************************************************** + + Synopsis [Computes f constrain c.] + + Description [Computes f constrain c (f @ c). + Uses a canonical form: (f' @ c) = ( f @ c)'. (Note: this is not true + for c.) List of special cases: + <ul> + <li> f @ 0 = 0 + <li> f @ 1 = f + <li> 0 @ c = 0 + <li> 1 @ c = 1 + <li> f @ f = 1 + <li> f @ f'= 0 + </ul> + Returns a pointer to the result if successful; NULL otherwise. Note that if + F=(f1,...,fn) and reordering takes place while computing F @ c, then the + image restriction property (Img(F,c) = Img(F @ c)) is lost.] + + SideEffects [None] + + SeeAlso [Cudd_bddRestrict Cudd_addConstrain] + +******************************************************************************/ +DdNode * +Cudd_bddConstrain( + DdManager * dd, + DdNode * f, + DdNode * c) +{ + DdNode *res; + + do { + dd->reordered = 0; + res = cuddBddConstrainRecur(dd,f,c); + } while (dd->reordered == 1); + return(res); + +} /* end of Cudd_bddConstrain */ + + +/**Function******************************************************************** + + Synopsis [BDD restrict according to Coudert and Madre's algorithm + (ICCAD90).] + + Description [BDD restrict according to Coudert and Madre's algorithm + (ICCAD90). Returns the restricted BDD if successful; otherwise NULL. + If application of restrict results in a BDD larger than the input + BDD, the input BDD is returned.] + + SideEffects [None] + + SeeAlso [Cudd_bddConstrain Cudd_addRestrict] + +******************************************************************************/ +DdNode * +Cudd_bddRestrict( + DdManager * dd, + DdNode * f, + DdNode * c) +{ + DdNode *suppF, *suppC, *commonSupport; + DdNode *cplus, *res; + int retval; + int sizeF, sizeRes; + + /* Check terminal cases here to avoid computing supports in trivial cases. + ** This also allows us notto check later for the case c == 0, in which + ** there is no common support. */ + if (c == Cudd_Not(DD_ONE(dd))) return(Cudd_Not(DD_ONE(dd))); + if (Cudd_IsConstant(f)) return(f); + if (f == c) return(DD_ONE(dd)); + if (f == Cudd_Not(c)) return(Cudd_Not(DD_ONE(dd))); + + /* Check if supports intersect. */ + retval = Cudd_ClassifySupport(dd,f,c,&commonSupport,&suppF,&suppC); + if (retval == 0) { + return(NULL); + } + cuddRef(commonSupport); cuddRef(suppF); cuddRef(suppC); + Cudd_IterDerefBdd(dd,suppF); + + if (commonSupport == DD_ONE(dd)) { + Cudd_IterDerefBdd(dd,commonSupport); + Cudd_IterDerefBdd(dd,suppC); + return(f); + } + Cudd_IterDerefBdd(dd,commonSupport); + + /* Abstract from c the variables that do not appear in f. */ + cplus = Cudd_bddExistAbstract(dd, c, suppC); + if (cplus == NULL) { + Cudd_IterDerefBdd(dd,suppC); + return(NULL); + } + cuddRef(cplus); + Cudd_IterDerefBdd(dd,suppC); + + do { + dd->reordered = 0; + res = cuddBddRestrictRecur(dd, f, cplus); + } while (dd->reordered == 1); + if (res == NULL) { + Cudd_IterDerefBdd(dd,cplus); + return(NULL); + } + cuddRef(res); + Cudd_IterDerefBdd(dd,cplus); + /* Make restric safe by returning the smaller of the input and the + ** result. */ + sizeF = Cudd_DagSize(f); + sizeRes = Cudd_DagSize(res); + if (sizeF <= sizeRes) { + Cudd_IterDerefBdd(dd, res); + return(f); + } else { + cuddDeref(res); + return(res); + } + +} /* end of Cudd_bddRestrict */ + + +/**Function******************************************************************** + + Synopsis [Computes f constrain c for ADDs.] + + Description [Computes f constrain c (f @ c), for f an ADD and c a 0-1 + ADD. List of special cases: + <ul> + <li> F @ 0 = 0 + <li> F @ 1 = F + <li> 0 @ c = 0 + <li> 1 @ c = 1 + <li> F @ F = 1 + </ul> + Returns a pointer to the result if successful; NULL otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_bddConstrain] + +******************************************************************************/ +DdNode * +Cudd_addConstrain( + DdManager * dd, + DdNode * f, + DdNode * c) +{ + DdNode *res; + + do { + dd->reordered = 0; + res = cuddAddConstrainRecur(dd,f,c); + } while (dd->reordered == 1); + return(res); + +} /* end of Cudd_addConstrain */ + + +/**Function******************************************************************** + + Synopsis [BDD conjunctive decomposition as in McMillan's CAV96 paper.] + + Description [BDD conjunctive decomposition as in McMillan's CAV96 + paper. The decomposition is canonical only for a given variable + order. If canonicity is required, variable ordering must be disabled + after the decomposition has been computed. Returns an array with one + entry for each BDD variable in the manager if successful; otherwise + NULL. The components of the solution have their reference counts + already incremented (unlike the results of most other functions in + the package.] + + SideEffects [None] + + SeeAlso [Cudd_bddConstrain Cudd_bddExistAbstract] + +******************************************************************************/ +DdNode ** +Cudd_bddConstrainDecomp( + DdManager * dd, + DdNode * f) +{ + DdNode **decomp; + int res; + int i; + + /* Create an initialize decomposition array. */ + decomp = ALLOC(DdNode *,dd->size); + if (decomp == NULL) { + dd->errorCode = CUDD_MEMORY_OUT; + return(NULL); + } + for (i = 0; i < dd->size; i++) { + decomp[i] = NULL; + } + do { + dd->reordered = 0; + /* Clean up the decomposition array in case reordering took place. */ + for (i = 0; i < dd->size; i++) { + if (decomp[i] != NULL) { + Cudd_IterDerefBdd(dd, decomp[i]); + decomp[i] = NULL; + } + } + res = cuddBddConstrainDecomp(dd,f,decomp); + } while (dd->reordered == 1); + if (res == 0) { + FREE(decomp); + return(NULL); + } + /* Missing components are constant ones. */ + for (i = 0; i < dd->size; i++) { + if (decomp[i] == NULL) { + decomp[i] = DD_ONE(dd); + cuddRef(decomp[i]); + } + } + return(decomp); + +} /* end of Cudd_bddConstrainDecomp */ + + +/**Function******************************************************************** + + Synopsis [ADD restrict according to Coudert and Madre's algorithm + (ICCAD90).] + + Description [ADD restrict according to Coudert and Madre's algorithm + (ICCAD90). Returns the restricted ADD if successful; otherwise NULL. + If application of restrict results in an ADD larger than the input + ADD, the input ADD is returned.] + + SideEffects [None] + + SeeAlso [Cudd_addConstrain Cudd_bddRestrict] + +******************************************************************************/ +DdNode * +Cudd_addRestrict( + DdManager * dd, + DdNode * f, + DdNode * c) +{ + DdNode *supp_f, *supp_c; + DdNode *res, *commonSupport; + int intersection; + int sizeF, sizeRes; + + /* Check if supports intersect. */ + supp_f = Cudd_Support(dd, f); + if (supp_f == NULL) { + return(NULL); + } + cuddRef(supp_f); + supp_c = Cudd_Support(dd, c); + if (supp_c == NULL) { + Cudd_RecursiveDeref(dd,supp_f); + return(NULL); + } + cuddRef(supp_c); + commonSupport = Cudd_bddLiteralSetIntersection(dd, supp_f, supp_c); + if (commonSupport == NULL) { + Cudd_RecursiveDeref(dd,supp_f); + Cudd_RecursiveDeref(dd,supp_c); + return(NULL); + } + cuddRef(commonSupport); + Cudd_RecursiveDeref(dd,supp_f); + Cudd_RecursiveDeref(dd,supp_c); + intersection = commonSupport != DD_ONE(dd); + Cudd_RecursiveDeref(dd,commonSupport); + + if (intersection) { + do { + dd->reordered = 0; + res = cuddAddRestrictRecur(dd, f, c); + } while (dd->reordered == 1); + sizeF = Cudd_DagSize(f); + sizeRes = Cudd_DagSize(res); + if (sizeF <= sizeRes) { + cuddRef(res); + Cudd_RecursiveDeref(dd, res); + return(f); + } else { + return(res); + } + } else { + return(f); + } + +} /* end of Cudd_addRestrict */ + + +/**Function******************************************************************** + + Synopsis [Computes a vector whose image equals a non-zero function.] + + Description [Computes a vector of BDDs whose image equals a non-zero + function. + The result depends on the variable order. The i-th component of the vector + depends only on the first i variables in the order. Each BDD in the vector + is not larger than the BDD of the given characteristic function. This + function is based on the description of char-to-vect in "Verification of + Sequential Machines Using Boolean Functional Vectors" by O. Coudert, C. + Berthet and J. C. Madre. + Returns a pointer to an array containing the result if successful; NULL + otherwise. The size of the array equals the number of variables in the + manager. The components of the solution have their reference counts + already incremented (unlike the results of most other functions in + the package.] + + SideEffects [None] + + SeeAlso [Cudd_bddConstrain] + +******************************************************************************/ +DdNode ** +Cudd_bddCharToVect( + DdManager * dd, + DdNode * f) +{ + int i, j; + DdNode **vect; + DdNode *res = NULL; + + if (f == Cudd_Not(DD_ONE(dd))) return(NULL); + + vect = ALLOC(DdNode *, dd->size); + if (vect == NULL) { + dd->errorCode = CUDD_MEMORY_OUT; + return(NULL); + } + + do { + dd->reordered = 0; + for (i = 0; i < dd->size; i++) { + res = cuddBddCharToVect(dd,f,dd->vars[dd->invperm[i]]); + if (res == NULL) { + /* Clean up the vector array in case reordering took place. */ + for (j = 0; j < i; j++) { + Cudd_IterDerefBdd(dd, vect[dd->invperm[j]]); + } + break; + } + cuddRef(res); + vect[dd->invperm[i]] = res; + } + } while (dd->reordered == 1); + if (res == NULL) { + FREE(vect); + return(NULL); + } + return(vect); + +} /* end of Cudd_bddCharToVect */ + + +/**Function******************************************************************** + + Synopsis [Performs safe minimization of a BDD.] + + Description [Performs safe minimization of a BDD. Given the BDD + <code>f</code> of a function to be minimized and a BDD + <code>c</code> representing the care set, Cudd_bddLICompaction + produces the BDD of a function that agrees with <code>f</code> + wherever <code>c</code> is 1. Safe minimization means that the size + of the result is guaranteed not to exceed the size of + <code>f</code>. This function is based on the DAC97 paper by Hong et + al.. Returns a pointer to the result if successful; NULL + otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_bddRestrict] + +******************************************************************************/ +DdNode * +Cudd_bddLICompaction( + DdManager * dd /* manager */, + DdNode * f /* function to be minimized */, + DdNode * c /* constraint (care set) */) +{ + DdNode *res; + + do { + dd->reordered = 0; + res = cuddBddLICompaction(dd,f,c); + } while (dd->reordered == 1); + return(res); + +} /* end of Cudd_bddLICompaction */ + + +/**Function******************************************************************** + + Synopsis [Finds a small BDD in a function interval.] + + Description [Finds a small BDD in a function interval. Given BDDs + <code>l</code> and <code>u</code>, representing the lower bound and + upper bound of a function interval, Cudd_bddSqueeze produces the BDD + of a function within the interval with a small BDD. Returns a + pointer to the result if successful; NULL otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_bddRestrict Cudd_bddLICompaction] + +******************************************************************************/ +DdNode * +Cudd_bddSqueeze( + DdManager * dd /* manager */, + DdNode * l /* lower bound */, + DdNode * u /* upper bound */) +{ + DdNode *res; + int sizeRes, sizeL, sizeU; + + do { + dd->reordered = 0; + res = cuddBddSqueeze(dd,l,u); + } while (dd->reordered == 1); + if (res == NULL) return(NULL); + /* We now compare the result with the bounds and return the smallest. + ** We first compare to u, so that in case l == 0 and u == 1, we return + ** 0 as in other minimization algorithms. */ + sizeRes = Cudd_DagSize(res); + sizeU = Cudd_DagSize(u); + if (sizeU <= sizeRes) { + cuddRef(res); + Cudd_IterDerefBdd(dd,res); + res = u; + sizeRes = sizeU; + } + sizeL = Cudd_DagSize(l); + if (sizeL <= sizeRes) { + cuddRef(res); + Cudd_IterDerefBdd(dd,res); + res = l; + sizeRes = sizeL; + } + return(res); + +} /* end of Cudd_bddSqueeze */ + + +/**Function******************************************************************** + + Synopsis [Finds a small BDD that agrees with <code>f</code> over + <code>c</code>.] + + Description [Finds a small BDD that agrees with <code>f</code> over + <code>c</code>. Returns a pointer to the result if successful; NULL + otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_bddRestrict Cudd_bddLICompaction Cudd_bddSqueeze] + +******************************************************************************/ +DdNode * +Cudd_bddMinimize( + DdManager * dd, + DdNode * f, + DdNode * c) +{ + DdNode *cplus, *res; + + if (c == Cudd_Not(DD_ONE(dd))) return(c); + if (Cudd_IsConstant(f)) return(f); + if (f == c) return(DD_ONE(dd)); + if (f == Cudd_Not(c)) return(Cudd_Not(DD_ONE(dd))); + + cplus = Cudd_RemapOverApprox(dd,c,0,0,1.0); + if (cplus == NULL) return(NULL); + cuddRef(cplus); + res = Cudd_bddLICompaction(dd,f,cplus); + if (res == NULL) { + Cudd_IterDerefBdd(dd,cplus); + return(NULL); + } + cuddRef(res); + Cudd_IterDerefBdd(dd,cplus); + cuddDeref(res); + return(res); + +} /* end of Cudd_bddMinimize */ + + +/**Function******************************************************************** + + Synopsis [Find a dense subset of BDD <code>f</code>.] + + Description [Finds a dense subset of BDD <code>f</code>. Density is + the ratio of number of minterms to number of nodes. Uses several + techniques in series. It is more expensive than other subsetting + procedures, but often produces better results. See + Cudd_SubsetShortPaths for a description of the threshold and nvars + parameters. Returns a pointer to the result if successful; NULL + otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_SubsetRemap Cudd_SubsetShortPaths Cudd_SubsetHeavyBranch + Cudd_bddSqueeze] + +******************************************************************************/ +DdNode * +Cudd_SubsetCompress( + DdManager * dd /* manager */, + DdNode * f /* BDD whose subset is sought */, + int nvars /* number of variables in the support of f */, + int threshold /* maximum number of nodes in the subset */) +{ + DdNode *res, *tmp1, *tmp2; + + tmp1 = Cudd_SubsetShortPaths(dd, f, nvars, threshold, 0); + if (tmp1 == NULL) return(NULL); + cuddRef(tmp1); + tmp2 = Cudd_RemapUnderApprox(dd,tmp1,nvars,0,1.0); + if (tmp2 == NULL) { + Cudd_IterDerefBdd(dd,tmp1); + return(NULL); + } + cuddRef(tmp2); + Cudd_IterDerefBdd(dd,tmp1); + res = Cudd_bddSqueeze(dd,tmp2,f); + if (res == NULL) { + Cudd_IterDerefBdd(dd,tmp2); + return(NULL); + } + cuddRef(res); + Cudd_IterDerefBdd(dd,tmp2); + cuddDeref(res); + return(res); + +} /* end of Cudd_SubsetCompress */ + + +/**Function******************************************************************** + + Synopsis [Find a dense superset of BDD <code>f</code>.] + + Description [Finds a dense superset of BDD <code>f</code>. Density is + the ratio of number of minterms to number of nodes. Uses several + techniques in series. It is more expensive than other supersetting + procedures, but often produces better results. See + Cudd_SupersetShortPaths for a description of the threshold and nvars + parameters. Returns a pointer to the result if successful; NULL + otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_SubsetCompress Cudd_SupersetRemap Cudd_SupersetShortPaths + Cudd_SupersetHeavyBranch Cudd_bddSqueeze] + +******************************************************************************/ +DdNode * +Cudd_SupersetCompress( + DdManager * dd /* manager */, + DdNode * f /* BDD whose superset is sought */, + int nvars /* number of variables in the support of f */, + int threshold /* maximum number of nodes in the superset */) +{ + DdNode *subset; + + subset = Cudd_SubsetCompress(dd, Cudd_Not(f),nvars,threshold); + + return(Cudd_NotCond(subset, (subset != NULL))); + +} /* end of Cudd_SupersetCompress */ + + +/*---------------------------------------------------------------------------*/ +/* Definition of internal functions */ +/*---------------------------------------------------------------------------*/ + + +/**Function******************************************************************** + + Synopsis [Performs the recursive step of Cudd_bddConstrain.] + + Description [Performs the recursive step of Cudd_bddConstrain. + Returns a pointer to the result if successful; NULL otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_bddConstrain] + +******************************************************************************/ +DdNode * +cuddBddConstrainRecur( + DdManager * dd, + DdNode * f, + DdNode * c) +{ + DdNode *Fv, *Fnv, *Cv, *Cnv, *t, *e, *r; + DdNode *one, *zero; + unsigned int topf, topc; + int index; + int comple = 0; + + statLine(dd); + one = DD_ONE(dd); + zero = Cudd_Not(one); + + /* Trivial cases. */ + if (c == one) return(f); + if (c == zero) return(zero); + if (Cudd_IsConstant(f)) return(f); + if (f == c) return(one); + if (f == Cudd_Not(c)) return(zero); + + /* Make canonical to increase the utilization of the cache. */ + if (Cudd_IsComplement(f)) { + f = Cudd_Not(f); + comple = 1; + } + /* Now f is a regular pointer to a non-constant node; c is also + ** non-constant, but may be complemented. + */ + + /* Check the cache. */ + r = cuddCacheLookup2(dd, Cudd_bddConstrain, f, c); + if (r != NULL) { + return(Cudd_NotCond(r,comple)); + } + + /* Recursive step. */ + topf = dd->perm[f->index]; + topc = dd->perm[Cudd_Regular(c)->index]; + if (topf <= topc) { + index = f->index; + Fv = cuddT(f); Fnv = cuddE(f); + } else { + index = Cudd_Regular(c)->index; + Fv = Fnv = f; + } + if (topc <= topf) { + Cv = cuddT(Cudd_Regular(c)); Cnv = cuddE(Cudd_Regular(c)); + if (Cudd_IsComplement(c)) { + Cv = Cudd_Not(Cv); + Cnv = Cudd_Not(Cnv); + } + } else { + Cv = Cnv = c; + } + + if (!Cudd_IsConstant(Cv)) { + t = cuddBddConstrainRecur(dd, Fv, Cv); + if (t == NULL) + return(NULL); + } else if (Cv == one) { + t = Fv; + } else { /* Cv == zero: return Fnv @ Cnv */ + if (Cnv == one) { + r = Fnv; + } else { + r = cuddBddConstrainRecur(dd, Fnv, Cnv); + if (r == NULL) + return(NULL); + } + return(Cudd_NotCond(r,comple)); + } + cuddRef(t); + + if (!Cudd_IsConstant(Cnv)) { + e = cuddBddConstrainRecur(dd, Fnv, Cnv); + if (e == NULL) { + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + } else if (Cnv == one) { + e = Fnv; + } else { /* Cnv == zero: return Fv @ Cv previously computed */ + cuddDeref(t); + return(Cudd_NotCond(t,comple)); + } + cuddRef(e); + + if (Cudd_IsComplement(t)) { + t = Cudd_Not(t); + e = Cudd_Not(e); + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + r = Cudd_Not(r); + } else { + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + } + cuddDeref(t); + cuddDeref(e); + + cuddCacheInsert2(dd, Cudd_bddConstrain, f, c, r); + return(Cudd_NotCond(r,comple)); + +} /* end of cuddBddConstrainRecur */ + + +/**Function******************************************************************** + + Synopsis [Performs the recursive step of Cudd_bddRestrict.] + + Description [Performs the recursive step of Cudd_bddRestrict. + Returns the restricted BDD if successful; otherwise NULL.] + + SideEffects [None] + + SeeAlso [Cudd_bddRestrict] + +******************************************************************************/ +DdNode * +cuddBddRestrictRecur( + DdManager * dd, + DdNode * f, + DdNode * c) +{ + DdNode *Fv, *Fnv, *Cv, *Cnv, *t, *e, *r, *one, *zero; + unsigned int topf, topc; + int index; + int comple = 0; + + statLine(dd); + one = DD_ONE(dd); + zero = Cudd_Not(one); + + /* Trivial cases */ + if (c == one) return(f); + if (c == zero) return(zero); + if (Cudd_IsConstant(f)) return(f); + if (f == c) return(one); + if (f == Cudd_Not(c)) return(zero); + + /* Make canonical to increase the utilization of the cache. */ + if (Cudd_IsComplement(f)) { + f = Cudd_Not(f); + comple = 1; + } + /* Now f is a regular pointer to a non-constant node; c is also + ** non-constant, but may be complemented. + */ + + /* Check the cache. */ + r = cuddCacheLookup2(dd, Cudd_bddRestrict, f, c); + if (r != NULL) { + return(Cudd_NotCond(r,comple)); + } + + topf = dd->perm[f->index]; + topc = dd->perm[Cudd_Regular(c)->index]; + + if (topc < topf) { /* abstract top variable from c */ + DdNode *d, *s1, *s2; + + /* Find complements of cofactors of c. */ + if (Cudd_IsComplement(c)) { + s1 = cuddT(Cudd_Regular(c)); + s2 = cuddE(Cudd_Regular(c)); + } else { + s1 = Cudd_Not(cuddT(c)); + s2 = Cudd_Not(cuddE(c)); + } + /* Take the OR by applying DeMorgan. */ + d = cuddBddAndRecur(dd, s1, s2); + if (d == NULL) return(NULL); + d = Cudd_Not(d); + cuddRef(d); + r = cuddBddRestrictRecur(dd, f, d); + if (r == NULL) { + Cudd_IterDerefBdd(dd, d); + return(NULL); + } + cuddRef(r); + Cudd_IterDerefBdd(dd, d); + cuddCacheInsert2(dd, Cudd_bddRestrict, f, c, r); + cuddDeref(r); + return(Cudd_NotCond(r,comple)); + } + + /* Recursive step. Here topf <= topc. */ + index = f->index; + Fv = cuddT(f); Fnv = cuddE(f); + if (topc == topf) { + Cv = cuddT(Cudd_Regular(c)); Cnv = cuddE(Cudd_Regular(c)); + if (Cudd_IsComplement(c)) { + Cv = Cudd_Not(Cv); + Cnv = Cudd_Not(Cnv); + } + } else { + Cv = Cnv = c; + } + + if (!Cudd_IsConstant(Cv)) { + t = cuddBddRestrictRecur(dd, Fv, Cv); + if (t == NULL) return(NULL); + } else if (Cv == one) { + t = Fv; + } else { /* Cv == zero: return(Fnv @ Cnv) */ + if (Cnv == one) { + r = Fnv; + } else { + r = cuddBddRestrictRecur(dd, Fnv, Cnv); + if (r == NULL) return(NULL); + } + return(Cudd_NotCond(r,comple)); + } + cuddRef(t); + + if (!Cudd_IsConstant(Cnv)) { + e = cuddBddRestrictRecur(dd, Fnv, Cnv); + if (e == NULL) { + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + } else if (Cnv == one) { + e = Fnv; + } else { /* Cnv == zero: return (Fv @ Cv) previously computed */ + cuddDeref(t); + return(Cudd_NotCond(t,comple)); + } + cuddRef(e); + + if (Cudd_IsComplement(t)) { + t = Cudd_Not(t); + e = Cudd_Not(e); + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + r = Cudd_Not(r); + } else { + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + } + cuddDeref(t); + cuddDeref(e); + + cuddCacheInsert2(dd, Cudd_bddRestrict, f, c, r); + return(Cudd_NotCond(r,comple)); + +} /* end of cuddBddRestrictRecur */ + + +/**Function******************************************************************** + + Synopsis [Performs the recursive step of Cudd_addConstrain.] + + Description [Performs the recursive step of Cudd_addConstrain. + Returns a pointer to the result if successful; NULL otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_addConstrain] + +******************************************************************************/ +DdNode * +cuddAddConstrainRecur( + DdManager * dd, + DdNode * f, + DdNode * c) +{ + DdNode *Fv, *Fnv, *Cv, *Cnv, *t, *e, *r; + DdNode *one, *zero; + unsigned int topf, topc; + int index; + + statLine(dd); + one = DD_ONE(dd); + zero = DD_ZERO(dd); + + /* Trivial cases. */ + if (c == one) return(f); + if (c == zero) return(zero); + if (Cudd_IsConstant(f)) return(f); + if (f == c) return(one); + + /* Now f and c are non-constant. */ + + /* Check the cache. */ + r = cuddCacheLookup2(dd, Cudd_addConstrain, f, c); + if (r != NULL) { + return(r); + } + + /* Recursive step. */ + topf = dd->perm[f->index]; + topc = dd->perm[c->index]; + if (topf <= topc) { + index = f->index; + Fv = cuddT(f); Fnv = cuddE(f); + } else { + index = c->index; + Fv = Fnv = f; + } + if (topc <= topf) { + Cv = cuddT(c); Cnv = cuddE(c); + } else { + Cv = Cnv = c; + } + + if (!Cudd_IsConstant(Cv)) { + t = cuddAddConstrainRecur(dd, Fv, Cv); + if (t == NULL) + return(NULL); + } else if (Cv == one) { + t = Fv; + } else { /* Cv == zero: return Fnv @ Cnv */ + if (Cnv == one) { + r = Fnv; + } else { + r = cuddAddConstrainRecur(dd, Fnv, Cnv); + if (r == NULL) + return(NULL); + } + return(r); + } + cuddRef(t); + + if (!Cudd_IsConstant(Cnv)) { + e = cuddAddConstrainRecur(dd, Fnv, Cnv); + if (e == NULL) { + Cudd_RecursiveDeref(dd, t); + return(NULL); + } + } else if (Cnv == one) { + e = Fnv; + } else { /* Cnv == zero: return Fv @ Cv previously computed */ + cuddDeref(t); + return(t); + } + cuddRef(e); + + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_RecursiveDeref(dd, e); + Cudd_RecursiveDeref(dd, t); + return(NULL); + } + cuddDeref(t); + cuddDeref(e); + + cuddCacheInsert2(dd, Cudd_addConstrain, f, c, r); + return(r); + +} /* end of cuddAddConstrainRecur */ + + +/**Function******************************************************************** + + Synopsis [Performs the recursive step of Cudd_addRestrict.] + + Description [Performs the recursive step of Cudd_addRestrict. + Returns the restricted ADD if successful; otherwise NULL.] + + SideEffects [None] + + SeeAlso [Cudd_addRestrict] + +******************************************************************************/ +DdNode * +cuddAddRestrictRecur( + DdManager * dd, + DdNode * f, + DdNode * c) +{ + DdNode *Fv, *Fnv, *Cv, *Cnv, *t, *e, *r, *one, *zero; + unsigned int topf, topc; + int index; + + statLine(dd); + one = DD_ONE(dd); + zero = DD_ZERO(dd); + + /* Trivial cases */ + if (c == one) return(f); + if (c == zero) return(zero); + if (Cudd_IsConstant(f)) return(f); + if (f == c) return(one); + + /* Now f and c are non-constant. */ + + /* Check the cache. */ + r = cuddCacheLookup2(dd, Cudd_addRestrict, f, c); + if (r != NULL) { + return(r); + } + + topf = dd->perm[f->index]; + topc = dd->perm[c->index]; + + if (topc < topf) { /* abstract top variable from c */ + DdNode *d, *s1, *s2; + + /* Find cofactors of c. */ + s1 = cuddT(c); + s2 = cuddE(c); + /* Take the OR by applying DeMorgan. */ + d = cuddAddApplyRecur(dd, Cudd_addOr, s1, s2); + if (d == NULL) return(NULL); + cuddRef(d); + r = cuddAddRestrictRecur(dd, f, d); + if (r == NULL) { + Cudd_RecursiveDeref(dd, d); + return(NULL); + } + cuddRef(r); + Cudd_RecursiveDeref(dd, d); + cuddCacheInsert2(dd, Cudd_addRestrict, f, c, r); + cuddDeref(r); + return(r); + } + + /* Recursive step. Here topf <= topc. */ + index = f->index; + Fv = cuddT(f); Fnv = cuddE(f); + if (topc == topf) { + Cv = cuddT(c); Cnv = cuddE(c); + } else { + Cv = Cnv = c; + } + + if (!Cudd_IsConstant(Cv)) { + t = cuddAddRestrictRecur(dd, Fv, Cv); + if (t == NULL) return(NULL); + } else if (Cv == one) { + t = Fv; + } else { /* Cv == zero: return(Fnv @ Cnv) */ + if (Cnv == one) { + r = Fnv; + } else { + r = cuddAddRestrictRecur(dd, Fnv, Cnv); + if (r == NULL) return(NULL); + } + return(r); + } + cuddRef(t); + + if (!Cudd_IsConstant(Cnv)) { + e = cuddAddRestrictRecur(dd, Fnv, Cnv); + if (e == NULL) { + Cudd_RecursiveDeref(dd, t); + return(NULL); + } + } else if (Cnv == one) { + e = Fnv; + } else { /* Cnv == zero: return (Fv @ Cv) previously computed */ + cuddDeref(t); + return(t); + } + cuddRef(e); + + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_RecursiveDeref(dd, e); + Cudd_RecursiveDeref(dd, t); + return(NULL); + } + cuddDeref(t); + cuddDeref(e); + + cuddCacheInsert2(dd, Cudd_addRestrict, f, c, r); + return(r); + +} /* end of cuddAddRestrictRecur */ + + + +/**Function******************************************************************** + + Synopsis [Performs safe minimization of a BDD.] + + Description [Performs safe minimization of a BDD. Given the BDD + <code>f</code> of a function to be minimized and a BDD + <code>c</code> representing the care set, Cudd_bddLICompaction + produces the BDD of a function that agrees with <code>f</code> + wherever <code>c</code> is 1. Safe minimization means that the size + of the result is guaranteed not to exceed the size of + <code>f</code>. This function is based on the DAC97 paper by Hong et + al.. Returns a pointer to the result if successful; NULL + otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_bddLICompaction] + +******************************************************************************/ +DdNode * +cuddBddLICompaction( + DdManager * dd /* manager */, + DdNode * f /* function to be minimized */, + DdNode * c /* constraint (care set) */) +{ + st_table *marktable, *markcache, *buildcache; + DdNode *res, *zero; + + zero = Cudd_Not(DD_ONE(dd)); + if (c == zero) return(zero); + + /* We need to use local caches for both steps of this operation. + ** The results of the edge marking step are only valid as long as the + ** edge markings themselves are available. However, the edge markings + ** are lost at the end of one invocation of Cudd_bddLICompaction. + ** Hence, the cache entries for the edge marking step must be + ** invalidated at the end of this function. + ** For the result of the building step we argue as follows. The result + ** for a node and a given constrain depends on the BDD in which the node + ** appears. Hence, the same node and constrain may give different results + ** in successive invocations. + */ + marktable = st_init_table(st_ptrcmp,st_ptrhash); + if (marktable == NULL) { + return(NULL); + } + markcache = st_init_table(MarkCacheCompare,MarkCacheHash); + if (markcache == NULL) { + st_free_table(marktable); + return(NULL); + } + if (cuddBddLICMarkEdges(dd,f,c,marktable,markcache) == CUDD_OUT_OF_MEM) { + st_foreach(markcache, MarkCacheCleanUp, NULL); + st_free_table(marktable); + st_free_table(markcache); + return(NULL); + } + st_foreach(markcache, MarkCacheCleanUp, NULL); + st_free_table(markcache); + buildcache = st_init_table(st_ptrcmp,st_ptrhash); + if (buildcache == NULL) { + st_free_table(marktable); + return(NULL); + } + res = cuddBddLICBuildResult(dd,f,buildcache,marktable); + st_free_table(buildcache); + st_free_table(marktable); + return(res); + +} /* end of cuddBddLICompaction */ + + +/*---------------------------------------------------------------------------*/ +/* Definition of static functions */ +/*---------------------------------------------------------------------------*/ + + +/**Function******************************************************************** + + Synopsis [Performs the recursive step of Cudd_bddConstrainDecomp.] + + Description [Performs the recursive step of Cudd_bddConstrainDecomp. + Returns f super (i) if successful; otherwise NULL.] + + SideEffects [None] + + SeeAlso [Cudd_bddConstrainDecomp] + +******************************************************************************/ +static int +cuddBddConstrainDecomp( + DdManager * dd, + DdNode * f, + DdNode ** decomp) +{ + DdNode *F, *fv, *fvn; + DdNode *fAbs; + DdNode *result; + int ok; + + if (Cudd_IsConstant(f)) return(1); + /* Compute complements of cofactors. */ + F = Cudd_Regular(f); + fv = cuddT(F); + fvn = cuddE(F); + if (F == f) { + fv = Cudd_Not(fv); + fvn = Cudd_Not(fvn); + } + /* Compute abstraction of top variable. */ + fAbs = cuddBddAndRecur(dd, fv, fvn); + if (fAbs == NULL) { + return(0); + } + cuddRef(fAbs); + fAbs = Cudd_Not(fAbs); + /* Recursively find the next abstraction and the components of the + ** decomposition. */ + ok = cuddBddConstrainDecomp(dd, fAbs, decomp); + if (ok == 0) { + Cudd_IterDerefBdd(dd,fAbs); + return(0); + } + /* Compute the component of the decomposition corresponding to the + ** top variable and store it in the decomposition array. */ + result = cuddBddConstrainRecur(dd, f, fAbs); + if (result == NULL) { + Cudd_IterDerefBdd(dd,fAbs); + return(0); + } + cuddRef(result); + decomp[F->index] = result; + Cudd_IterDerefBdd(dd, fAbs); + return(1); + +} /* end of cuddBddConstrainDecomp */ + + +/**Function******************************************************************** + + Synopsis [Performs the recursive step of Cudd_bddCharToVect.] + + Description [Performs the recursive step of Cudd_bddCharToVect. + This function maintains the invariant that f is non-zero. + Returns the i-th component of the vector if successful; otherwise NULL.] + + SideEffects [None] + + SeeAlso [Cudd_bddCharToVect] + +******************************************************************************/ +static DdNode * +cuddBddCharToVect( + DdManager * dd, + DdNode * f, + DdNode * x) +{ + unsigned int topf; + unsigned int level; + int comple; + + DdNode *one, *zero, *res, *F, *fT, *fE, *T, *E; + + statLine(dd); + /* Check the cache. */ + res = cuddCacheLookup2(dd, cuddBddCharToVect, f, x); + if (res != NULL) { + return(res); + } + + F = Cudd_Regular(f); + + topf = cuddI(dd,F->index); + level = dd->perm[x->index]; + + if (topf > level) return(x); + + one = DD_ONE(dd); + zero = Cudd_Not(one); + + comple = F != f; + fT = Cudd_NotCond(cuddT(F),comple); + fE = Cudd_NotCond(cuddE(F),comple); + + if (topf == level) { + if (fT == zero) return(zero); + if (fE == zero) return(one); + return(x); + } + + /* Here topf < level. */ + if (fT == zero) return(cuddBddCharToVect(dd, fE, x)); + if (fE == zero) return(cuddBddCharToVect(dd, fT, x)); + + T = cuddBddCharToVect(dd, fT, x); + if (T == NULL) { + return(NULL); + } + cuddRef(T); + E = cuddBddCharToVect(dd, fE, x); + if (E == NULL) { + Cudd_IterDerefBdd(dd,T); + return(NULL); + } + cuddRef(E); + res = cuddBddIteRecur(dd, dd->vars[F->index], T, E); + if (res == NULL) { + Cudd_IterDerefBdd(dd,T); + Cudd_IterDerefBdd(dd,E); + return(NULL); + } + cuddDeref(T); + cuddDeref(E); + cuddCacheInsert2(dd, cuddBddCharToVect, f, x, res); + return(res); + +} /* end of cuddBddCharToVect */ + + +/**Function******************************************************************** + + Synopsis [Performs the edge marking step of Cudd_bddLICompaction.] + + Description [Performs the edge marking step of Cudd_bddLICompaction. + Returns the LUB of the markings of the two outgoing edges of <code>f</code> + if successful; otherwise CUDD_OUT_OF_MEM.] + + SideEffects [None] + + SeeAlso [Cudd_bddLICompaction cuddBddLICBuildResult] + +******************************************************************************/ +static int +cuddBddLICMarkEdges( + DdManager * dd, + DdNode * f, + DdNode * c, + st_table * table, + st_table * cache) +{ + DdNode *Fv, *Fnv, *Cv, *Cnv; + DdNode *one, *zero; + unsigned int topf, topc; + int index; + int comple; + int resT, resE, res, retval; + char **slot; + MarkCacheKey *key; + + one = DD_ONE(dd); + zero = Cudd_Not(one); + + /* Terminal cases. */ + if (c == zero) return(DD_LIC_DC); + if (f == one) return(DD_LIC_1); + if (f == zero) return(DD_LIC_0); + + /* Make canonical to increase the utilization of the cache. */ + comple = Cudd_IsComplement(f); + f = Cudd_Regular(f); + /* Now f is a regular pointer to a non-constant node; c may be + ** constant, or it may be complemented. + */ + + /* Check the cache. */ + key = ALLOC(MarkCacheKey, 1); + if (key == NULL) { + dd->errorCode = CUDD_MEMORY_OUT; + return(CUDD_OUT_OF_MEM); + } + key->f = f; key->c = c; + if (st_lookup(cache, (char *)key, (char **)&res)) { + FREE(key); + if (comple) { + if (res == DD_LIC_0) res = DD_LIC_1; + else if (res == DD_LIC_1) res = DD_LIC_0; + } + return(res); + } + + /* Recursive step. */ + topf = dd->perm[f->index]; + topc = cuddI(dd,Cudd_Regular(c)->index); + if (topf <= topc) { + index = f->index; + Fv = cuddT(f); Fnv = cuddE(f); + } else { + index = Cudd_Regular(c)->index; + Fv = Fnv = f; + } + if (topc <= topf) { + /* We know that c is not constant because f is not. */ + Cv = cuddT(Cudd_Regular(c)); Cnv = cuddE(Cudd_Regular(c)); + if (Cudd_IsComplement(c)) { + Cv = Cudd_Not(Cv); + Cnv = Cudd_Not(Cnv); + } + } else { + Cv = Cnv = c; + } + + resT = cuddBddLICMarkEdges(dd, Fv, Cv, table, cache); + if (resT == CUDD_OUT_OF_MEM) { + FREE(key); + return(CUDD_OUT_OF_MEM); + } + resE = cuddBddLICMarkEdges(dd, Fnv, Cnv, table, cache); + if (resE == CUDD_OUT_OF_MEM) { + FREE(key); + return(CUDD_OUT_OF_MEM); + } + + /* Update edge markings. */ + if (topf <= topc) { + retval = st_find_or_add(table, (char *)f, (char ***)&slot); + if (retval == 0) { + *slot = (char *) (ptrint)((resT << 2) | resE); + } else if (retval == 1) { + *slot = (char *) (ptrint)((int)((ptrint) *slot) | (resT << 2) | resE); + } else { + FREE(key); + return(CUDD_OUT_OF_MEM); + } + } + + /* Cache result. */ + res = resT | resE; + if (st_insert(cache, (char *)key, (char *)(ptrint)res) == ST_OUT_OF_MEM) { + FREE(key); + return(CUDD_OUT_OF_MEM); + } + + /* Take into account possible complementation. */ + if (comple) { + if (res == DD_LIC_0) res = DD_LIC_1; + else if (res == DD_LIC_1) res = DD_LIC_0; + } + return(res); + +} /* end of cuddBddLICMarkEdges */ + + +/**Function******************************************************************** + + Synopsis [Builds the result of Cudd_bddLICompaction.] + + Description [Builds the results of Cudd_bddLICompaction. + Returns a pointer to the minimized BDD if successful; otherwise NULL.] + + SideEffects [None] + + SeeAlso [Cudd_bddLICompaction cuddBddLICMarkEdges] + +******************************************************************************/ +static DdNode * +cuddBddLICBuildResult( + DdManager * dd, + DdNode * f, + st_table * cache, + st_table * table) +{ + DdNode *Fv, *Fnv, *r, *t, *e; + DdNode *one, *zero; + unsigned int topf; + int index; + int comple; + int markT, markE, markings; + + one = DD_ONE(dd); + zero = Cudd_Not(one); + + if (Cudd_IsConstant(f)) return(f); + /* Make canonical to increase the utilization of the cache. */ + comple = Cudd_IsComplement(f); + f = Cudd_Regular(f); + + /* Check the cache. */ + if (st_lookup(cache, (char *)f, (char **)&r)) { + return(Cudd_NotCond(r,comple)); + } + + /* Retrieve the edge markings. */ + if (st_lookup(table, (char *)f, (char **)&markings) == 0) + return(NULL); + markT = markings >> 2; + markE = markings & 3; + + topf = dd->perm[f->index]; + index = f->index; + Fv = cuddT(f); Fnv = cuddE(f); + + if (markT == DD_LIC_NL) { + t = cuddBddLICBuildResult(dd,Fv,cache,table); + if (t == NULL) { + return(NULL); + } + } else if (markT == DD_LIC_1) { + t = one; + } else { + t = zero; + } + cuddRef(t); + if (markE == DD_LIC_NL) { + e = cuddBddLICBuildResult(dd,Fnv,cache,table); + if (e == NULL) { + Cudd_IterDerefBdd(dd,t); + return(NULL); + } + } else if (markE == DD_LIC_1) { + e = one; + } else { + e = zero; + } + cuddRef(e); + + if (markT == DD_LIC_DC && markE != DD_LIC_DC) { + r = e; + } else if (markT != DD_LIC_DC && markE == DD_LIC_DC) { + r = t; + } else { + if (Cudd_IsComplement(t)) { + t = Cudd_Not(t); + e = Cudd_Not(e); + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + r = Cudd_Not(r); + } else { + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + } + } + cuddDeref(t); + cuddDeref(e); + + if (st_insert(cache, (char *)f, (char *)r) == ST_OUT_OF_MEM) { + cuddRef(r); + Cudd_IterDerefBdd(dd,r); + return(NULL); + } + + return(Cudd_NotCond(r,comple)); + +} /* end of cuddBddLICBuildResult */ + + +/**Function******************************************************************** + + Synopsis [Hash function for the computed table of cuddBddLICMarkEdges.] + + Description [Hash function for the computed table of + cuddBddLICMarkEdges. Returns the bucket number.] + + SideEffects [None] + + SeeAlso [Cudd_bddLICompaction] + +******************************************************************************/ +static int +MarkCacheHash( + char * ptr, + int modulus) +{ + int val = 0; + MarkCacheKey *entry; + + entry = (MarkCacheKey *) ptr; + + val = (int) (ptrint) entry->f; + val = val * 997 + (int) (ptrint) entry->c; + + return ((val < 0) ? -val : val) % modulus; + +} /* end of MarkCacheHash */ + + +/**Function******************************************************************** + + Synopsis [Comparison function for the computed table of + cuddBddLICMarkEdges.] + + Description [Comparison function for the computed table of + cuddBddLICMarkEdges. Returns 0 if the two nodes of the key are equal; 1 + otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_bddLICompaction] + +******************************************************************************/ +static int +MarkCacheCompare( + const char * ptr1, + const char * ptr2) +{ + MarkCacheKey *entry1, *entry2; + + entry1 = (MarkCacheKey *) ptr1; + entry2 = (MarkCacheKey *) ptr2; + + return((entry1->f != entry2->f) || (entry1->c != entry2->c)); + +} /* end of MarkCacheCompare */ + + + +/**Function******************************************************************** + + Synopsis [Frees memory associated with computed table of + cuddBddLICMarkEdges.] + + Description [Frees memory associated with computed table of + cuddBddLICMarkEdges. Returns ST_CONTINUE.] + + SideEffects [None] + + SeeAlso [Cudd_bddLICompaction] + +******************************************************************************/ +static enum st_retval +MarkCacheCleanUp( + char * key, + char * value, + char * arg) +{ + MarkCacheKey *entry; + + entry = (MarkCacheKey *) key; + FREE(entry); + return ST_CONTINUE; + +} /* end of MarkCacheCleanUp */ + + +/**Function******************************************************************** + + Synopsis [Performs the recursive step of Cudd_bddSqueeze.] + + Description [Performs the recursive step of Cudd_bddSqueeze. This + procedure exploits the fact that if we complement and swap the + bounds of the interval we obtain a valid solution by taking the + complement of the solution to the original problem. Therefore, we + can enforce the condition that the upper bound is always regular. + Returns a pointer to the result if successful; NULL otherwise.] + + SideEffects [None] + + SeeAlso [Cudd_bddSqueeze] + +******************************************************************************/ +static DdNode * +cuddBddSqueeze( + DdManager * dd, + DdNode * l, + DdNode * u) +{ + DdNode *one, *zero, *r, *lt, *le, *ut, *ue, *t, *e; +#if 0 + DdNode *ar; +#endif + int comple = 0; + unsigned int topu, topl; + int index; + + statLine(dd); + if (l == u) { + return(l); + } + one = DD_ONE(dd); + zero = Cudd_Not(one); + /* The only case when l == zero && u == one is at the top level, + ** where returning either one or zero is OK. In all other cases + ** the procedure will detect such a case and will perform + ** remapping. Therefore the order in which we test l and u at this + ** point is immaterial. */ + if (l == zero) return(l); + if (u == one) return(u); + + /* Make canonical to increase the utilization of the cache. */ + if (Cudd_IsComplement(u)) { + DdNode *temp; + temp = Cudd_Not(l); + l = Cudd_Not(u); + u = temp; + comple = 1; + } + /* At this point u is regular and non-constant; l is non-constant, but + ** may be complemented. */ + + /* Here we could check the relative sizes. */ + + /* Check the cache. */ + r = cuddCacheLookup2(dd, Cudd_bddSqueeze, l, u); + if (r != NULL) { + return(Cudd_NotCond(r,comple)); + } + + /* Recursive step. */ + topu = dd->perm[u->index]; + topl = dd->perm[Cudd_Regular(l)->index]; + if (topu <= topl) { + index = u->index; + ut = cuddT(u); ue = cuddE(u); + } else { + index = Cudd_Regular(l)->index; + ut = ue = u; + } + if (topl <= topu) { + lt = cuddT(Cudd_Regular(l)); le = cuddE(Cudd_Regular(l)); + if (Cudd_IsComplement(l)) { + lt = Cudd_Not(lt); + le = Cudd_Not(le); + } + } else { + lt = le = l; + } + + /* If one interval is contained in the other, use the smaller + ** interval. This corresponds to one-sided matching. */ + if ((lt == zero || Cudd_bddLeq(dd,lt,le)) && + (ut == one || Cudd_bddLeq(dd,ue,ut))) { /* remap */ + r = cuddBddSqueeze(dd, le, ue); + if (r == NULL) + return(NULL); + return(Cudd_NotCond(r,comple)); + } else if ((le == zero || Cudd_bddLeq(dd,le,lt)) && + (ue == one || Cudd_bddLeq(dd,ut,ue))) { /* remap */ + r = cuddBddSqueeze(dd, lt, ut); + if (r == NULL) + return(NULL); + return(Cudd_NotCond(r,comple)); + } else if ((le == zero || Cudd_bddLeq(dd,le,Cudd_Not(ut))) && + (ue == one || Cudd_bddLeq(dd,Cudd_Not(lt),ue))) { /* c-remap */ + t = cuddBddSqueeze(dd, lt, ut); + cuddRef(t); + if (Cudd_IsComplement(t)) { + r = cuddUniqueInter(dd, index, Cudd_Not(t), t); + if (r == NULL) { + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + r = Cudd_Not(r); + } else { + r = cuddUniqueInter(dd, index, t, Cudd_Not(t)); + if (r == NULL) { + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + } + cuddDeref(t); + if (r == NULL) + return(NULL); + cuddCacheInsert2(dd, Cudd_bddSqueeze, l, u, r); + return(Cudd_NotCond(r,comple)); + } else if ((lt == zero || Cudd_bddLeq(dd,lt,Cudd_Not(ue))) && + (ut == one || Cudd_bddLeq(dd,Cudd_Not(le),ut))) { /* c-remap */ + e = cuddBddSqueeze(dd, le, ue); + cuddRef(e); + if (Cudd_IsComplement(e)) { + r = cuddUniqueInter(dd, index, Cudd_Not(e), e); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + return(NULL); + } + } else { + r = cuddUniqueInter(dd, index, e, Cudd_Not(e)); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + return(NULL); + } + r = Cudd_Not(r); + } + cuddDeref(e); + if (r == NULL) + return(NULL); + cuddCacheInsert2(dd, Cudd_bddSqueeze, l, u, r); + return(Cudd_NotCond(r,comple)); + } + +#if 0 + /* If the two intervals intersect, take a solution from + ** the intersection of the intervals. This guarantees that the + ** splitting variable will not appear in the result. + ** This approach corresponds to two-sided matching, and is very + ** expensive. */ + if (Cudd_bddLeq(dd,lt,ue) && Cudd_bddLeq(dd,le,ut)) { + DdNode *au, *al; + au = cuddBddAndRecur(dd,ut,ue); + if (au == NULL) + return(NULL); + cuddRef(au); + al = cuddBddAndRecur(dd,Cudd_Not(lt),Cudd_Not(le)); + if (al == NULL) { + Cudd_IterDerefBdd(dd,au); + return(NULL); + } + cuddRef(al); + al = Cudd_Not(al); + ar = cuddBddSqueeze(dd, al, au); + if (ar == NULL) { + Cudd_IterDerefBdd(dd,au); + Cudd_IterDerefBdd(dd,al); + return(NULL); + } + cuddRef(ar); + Cudd_IterDerefBdd(dd,au); + Cudd_IterDerefBdd(dd,al); + } else { + ar = NULL; + } +#endif + + t = cuddBddSqueeze(dd, lt, ut); + if (t == NULL) { + return(NULL); + } + cuddRef(t); + e = cuddBddSqueeze(dd, le, ue); + if (e == NULL) { + Cudd_IterDerefBdd(dd,t); + return(NULL); + } + cuddRef(e); + + if (Cudd_IsComplement(t)) { + t = Cudd_Not(t); + e = Cudd_Not(e); + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + r = Cudd_Not(r); + } else { + r = (t == e) ? t : cuddUniqueInter(dd, index, t, e); + if (r == NULL) { + Cudd_IterDerefBdd(dd, e); + Cudd_IterDerefBdd(dd, t); + return(NULL); + } + } + cuddDeref(t); + cuddDeref(e); + +#if 0 + /* Check whether there is a result obtained by abstraction and whether + ** it is better than the one obtained by recursion. */ + cuddRef(r); + if (ar != NULL) { + if (Cudd_DagSize(ar) <= Cudd_DagSize(r)) { + Cudd_IterDerefBdd(dd, r); + r = ar; + } else { + Cudd_IterDerefBdd(dd, ar); + } + } + cuddDeref(r); +#endif + + cuddCacheInsert2(dd, Cudd_bddSqueeze, l, u, r); + return(Cudd_NotCond(r,comple)); + +} /* end of cuddBddSqueeze */ |