// 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 uint8_t 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 uint8_t card_deck; static const cell deck_bits = card_bits + 10; // Number of bytes on the heap a deck addresses. Each deck as 1024 // cards. So 256 kb. static const cell deck_size = 1 << deck_bits; static const cell cards_per_deck = 1 << 10; inline cell addr_to_card(cell a) { return a >> card_bits; } inline cell addr_to_deck(cell a) { return a >> deck_bits; } }