/*
NAME {* bdd\_delref *}
SECTION {* kernel *}
SHORT {* decreases the reference count on a node *}
PROTO {* BDD bdd_delref(BDD r) *}
DESCR {* Reference counting is done on externaly referenced nodes only
and the count for a specific node {\tt r} can and must be
decreased using this function to make it possible to reclaim the
node in the next garbage collection. *}
ALSO {* bdd\_addref *}
RETURN {* The BDD node {\tt r}. *}
*/
BDD bdd_delref(BDD root)
{
BUDDY_PROLOGUE;
ADD_ARG1(T_BDD,root);
if (root < 2 || !bddrunning)
RETURN_BDD(root);
if (root >= bddnodesize)
RETURN_BDD(bdd_error(BDD_ILLBDD));
if (LOW(root) == INVALID_BDD)
RETURN_BDD(bdd_error(BDD_ILLBDD));
/* if the following line is present, fails there much earlier */
if (!HASREF(root))
bdd_error(BDD_BREAK); /* distinctive */
DECREF(root);
if(!HASREF(root))
trace_del_bdd(T_BDD,(void *)root);
RETURN_BDD(root);
}
/*
NAME {* bdd\_delref *}
SECTION {* kernel *}
SHORT {* decreases the reference count on a node *}
PROTO {* BDD bdd_delref(BDD r) *}
DESCR {* Reference counting is done on externaly referenced nodes only
and the count for a specific node {\tt r} can and must be
decreased using this function to make it possible to reclaim the
node in the next garbage collection. *}
ALSO {* bdd\_addref *}
RETURN {* The BDD node {\tt r}. *}
*/
BDD bdd_delref(BDD root)
{
if (root < 2 || !bddrunning)
return root;
if (root >= bddnodesize)
return bdd_error(BDD_ILLBDD);
if (LOW(root) == -1)
return bdd_error(BDD_ILLBDD);
/* if the following line is present, fails there much earlier */
if (!HASREF(root)) bdd_error(BDD_BREAK); /* distinctive */
DECREF(root);
return root;
}
void bdd_gbc(void)
{
int *r;
int n;
long int c2, c1 = clock();
if (gbc_handler != NULL)
{
bddGbcStat s;
s.nodes = bddnodesize;
s.freenodes = bddfreenum;
s.time = 0;
s.sumtime = gbcclock;
s.num = gbcollectnum;
gbc_handler(1, &s);
}
for (r=bddrefstack ; r<bddrefstacktop ; r++)
bdd_mark(*r);
for (n=0 ; n<bddnodesize ; n++)
{
if (HASREF(n)) bdd_mark(n);
SETHASH(n, 0);
}
bddfreepos = 0;
bddfreenum = 0;
for (n=bddnodesize-1 ; n>=2 ; n--)
{
register BddNode *node = &bddnodes[n];
if (MARKEDp(node) && LOWp(node) != INVALID_BDD)
{
register unsigned int hash;
UNMARKp(node);
hash = NODEHASH(LEVELp(node), LOWp(node), HIGHp(node));
SETNEXTp(node, HASH(hash));
SETHASH(hash, n);
}
else
{
SETLOWpz(node, INVALID_BDD); // obliterates refcount
SETNEXTpz(node, bddfreepos); // obliterates lev, mark
bddfreepos = n;
bddfreenum++;
}
}
bdd_operator_reset();
c2 = clock();
gbcclock += c2-c1;
gbcollectnum++;
if (gbc_handler != NULL)
{
bddGbcStat s;
s.nodes = bddnodesize;
s.freenodes = bddfreenum;
s.time = c2-c1;
s.sumtime = gbcclock;
s.num = gbcollectnum;
gbc_handler(0, &s);
}
}
