factor/vm/object_start_map.cpp

77 lines
2.4 KiB
C++

#include "master.hpp"
namespace factor {
object_start_map::object_start_map(cell size, cell start)
: size(size), start(start) {
object_start_offsets = new card[addr_to_card(size)];
object_start_offsets_end = object_start_offsets + addr_to_card(size);
clear_object_start_offsets();
}
object_start_map::~object_start_map() { delete[] object_start_offsets; }
cell object_start_map::first_object_in_card(cell card_index) {
return object_start_offsets[card_index];
}
cell object_start_map::find_object_containing_card(cell card_index) {
if (card_index == 0)
return start;
else {
card_index--;
while (first_object_in_card(card_index) == card_starts_inside_object) {
/* First card should start with an object */
FACTOR_ASSERT(card_index > 0);
card_index--;
}
return start + (card_index << card_bits) + first_object_in_card(card_index);
}
}
/* we need to remember the first object allocated in the card */
void object_start_map::record_object_start_offset(object* obj) {
cell idx = addr_to_card((cell)obj - start);
card obj_start = ((cell)obj & addr_card_mask);
object_start_offsets[idx] = std::min(object_start_offsets[idx], obj_start);
}
void object_start_map::clear_object_start_offsets() {
memset(object_start_offsets, card_starts_inside_object, addr_to_card(size));
}
void object_start_map::update_card_for_sweep(cell index, uint16_t mask) {
cell offset = object_start_offsets[index];
if (offset != card_starts_inside_object) {
mask >>= (offset / data_alignment);
if (mask == 0) {
/* The rest of the block after the old object start is free */
object_start_offsets[index] = card_starts_inside_object;
} else {
/* Move the object start forward if necessary */
object_start_offsets[index] =
(card)(offset + (rightmost_set_bit(mask) * data_alignment));
}
}
}
void object_start_map::update_for_sweep(mark_bits<object>* state) {
for (cell index = 0; index < state->bits_size; index++) {
cell mask = state->marked[index];
#ifdef FACTOR_64
update_card_for_sweep(index * 4, mask & 0xffff);
update_card_for_sweep(index * 4 + 1, (mask >> 16) & 0xffff);
update_card_for_sweep(index * 4 + 2, (mask >> 32) & 0xffff);
update_card_for_sweep(index * 4 + 3, (mask >> 48) & 0xffff);
#else
update_card_for_sweep(index * 2, mask & 0xffff);
update_card_for_sweep(index * 2 + 1, (mask >> 16) & 0xffff);
#endif
}
}
}