/* card marking write barrier. a card is a byte storing a mark flag, and the offset (in cells) of the first object in the card. the mark flag is set by the write barrier when an object in the card has a slot written to. the offset of the first object is set by the allocator. */ namespace factor { /* if card_points_to_nursery is set, card_points_to_aging must also be set. */ static const cell card_points_to_nursery = 0x80; static const cell card_points_to_aging = 0x40; static const cell card_mark_mask = (card_points_to_nursery | card_points_to_aging); typedef u8 card; static const cell card_bits = 8; static const cell card_size = (1 << card_bits); static const cell addr_card_mask = (card_size - 1); typedef u8 card_deck; static const cell deck_bits = (card_bits + 10); static const cell deck_size = (1 << deck_bits); static const cell addr_deck_mask = (deck_size - 1); inline cell addr_to_card(cell a) { return a >> card_bits; } inline cell addr_to_deck(cell a) { return a >> deck_bits; } }