diff options
Diffstat (limited to 'runtime/gc/accounting')
| -rw-r--r-- | runtime/gc/accounting/card_table-inl.h | 28 |
1 files changed, 16 insertions, 12 deletions
diff --git a/runtime/gc/accounting/card_table-inl.h b/runtime/gc/accounting/card_table-inl.h index f0c4d0d788..841f4ae3e1 100644 --- a/runtime/gc/accounting/card_table-inl.h +++ b/runtime/gc/accounting/card_table-inl.h @@ -154,26 +154,30 @@ inline void CardTable::ModifyCardsAtomic(byte* scan_begin, byte* scan_end, const // Now we have the words, we can process words in parallel. uintptr_t* word_cur = reinterpret_cast<uintptr_t*>(card_cur); uintptr_t* word_end = reinterpret_cast<uintptr_t*>(card_end); - uintptr_t expected_word; - uintptr_t new_word; + union { + uintptr_t expected_word; + uint8_t expected_bytes[sizeof(uintptr_t)]; + }; + union { + uintptr_t new_word; + uint8_t new_bytes[sizeof(uintptr_t)]; + }; // TODO: Parallelize. while (word_cur < word_end) { - while ((expected_word = *word_cur) != 0) { - new_word = - (visitor((expected_word >> 0) & 0xFF) << 0) | - (visitor((expected_word >> 8) & 0xFF) << 8) | - (visitor((expected_word >> 16) & 0xFF) << 16) | - (visitor((expected_word >> 24) & 0xFF) << 24); - if (new_word == expected_word) { - // No need to do a cas. + while (true) { + expected_word = *word_cur; + if (LIKELY(expected_word == 0)) { break; } + for (size_t i = 0; i < sizeof(uintptr_t); ++i) { + new_bytes[i] = visitor(expected_bytes[i]); + } if (LIKELY(android_atomic_cas(expected_word, new_word, reinterpret_cast<int32_t*>(word_cur)) == 0)) { for (size_t i = 0; i < sizeof(uintptr_t); ++i) { - const byte expected_byte = (expected_word >> (8 * i)) & 0xFF; - const byte new_byte = (new_word >> (8 * i)) & 0xFF; + const byte expected_byte = expected_bytes[i]; + const byte new_byte = new_bytes[i]; if (expected_byte != new_byte) { modified(reinterpret_cast<byte*>(word_cur) + i, expected_byte, new_byte); } |