34 lines
1.1 KiB
C++
34 lines
1.1 KiB
C++
// card marking write barrier. a card is a byte storing a mark flag,
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// and the offset (in cells) of the first object in the card.
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// the mark flag is set by the write barrier when an object in the
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// card has a slot written to.
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// the offset of the first object is set by the allocator.
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namespace factor {
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// if card_points_to_nursery is set, card_points_to_aging must also be set.
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static const cell card_points_to_nursery = 0x80;
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static const cell card_points_to_aging = 0x40;
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static const cell card_mark_mask =
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(card_points_to_nursery | card_points_to_aging);
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typedef uint8_t card;
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static const cell card_bits = 8;
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static const cell card_size = 1 << card_bits;
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static const cell addr_card_mask = card_size - 1;
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typedef uint8_t card_deck;
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static const cell deck_bits = card_bits + 10;
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// Number of bytes on the heap a deck addresses. Each deck as 1024
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// cards. So 256 kb.
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static const cell deck_size = 1 << deck_bits;
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static const cell cards_per_deck = 1 << 10;
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inline cell addr_to_card(cell a) { return a >> card_bits; }
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inline cell addr_to_deck(cell a) { return a >> deck_bits; }
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}
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