/* A couple ways to speed this up:
- inline push_constituents
- Cache the stack pointer, stack bottom, and stack limit in
register variables to avoid the loads and stores; compiler is
unlikely to do this.
- Back-to-back push/pop pairs, like when pushing the car of a pair
and then looping around to pop it again can be joined.
*/
static void mark_from_stack( msgc_context_t *context )
{
word w;
word first = (word)context->lowest_heap_address;
word *bitmap = context->bitmap;
int traced=0, marked=0, words_marked=0;
bool already_marked;
while (! context->signal_stop) {
/* Pop */
if (context->stack.stkp == context->stack.stkbot) /* Stack underflow */
if (!pop_segment( &context->stack )) {
if (fill_from_los_stack( context ))
continue;
else
break;
}
w = *--context->stack.stkp;
traced++;
/* Mark */
already_marked = my_mark_object( context, w );
if (already_marked) continue;
marked++;
words_marked += push_constituents( context, w );
}
context->traced += traced;
context->marked += marked;
context->words_marked += words_marked;
}
/* A couple ways to speed this up:
- inline push_constituents
- Cache the stack pointer, stack bottom, and stack limit in
register variables to avoid the loads and stores; compiler is
unlikely to do this.
- Back-to-back push/pop pairs, like when pushing the car of a pair
and then looping around to pop it again can be joined.
*/
static void mark_from_stack( msgc_context_t *context )
{
word w, bit_idx, word_idx, bit;
word first = (word)context->lowest_heap_address;
word *bitmap = context->bitmap;
int traced=0, marked=0, words_marked=0;
while (1) {
/* Pop */
if (context->stack.stkp == context->stack.stkbot) /* Stack underflow */
if (!pop_segment( &context->stack ))
if (fill_from_los_stack( context ))
continue;
else
break;
w = *--context->stack.stkp;
traced++;
/* Mark */
/* Note: marks object only, not entire address range occupied
by object. A "real" collector must mark the range.
*/
bit_idx = (w - first) >> BIT_IDX_SHIFT;
word_idx = bit_idx >> BITS_TO_WORDS;
bit = 1 << (bit_idx & BIT_IN_WORD_MASK);
if (bitmap[ word_idx ] & bit) continue; /* Already marked */
bitmap[ word_idx ] |= bit;
marked++;
words_marked += push_constituents( context, w );
}
context->traced += traced;
context->marked += marked;
context->words_marked += words_marked;
}