jdk8-mips64-public/hotspot: src/share/vm/utilities/bitMap.inline.hpp@9f4457a14b58

     1 /*

     2  * Copyright 2005-2006 Sun Microsystems, Inc.  All Rights Reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    25 inline bool BitMap::par_set_bit(idx_t bit) {

    26   verify_index(bit);

    27   volatile idx_t* const addr = word_addr(bit);

    28   const idx_t mask = bit_mask(bit);

    29   idx_t old_val = *addr;

    31   do {

    32     const idx_t new_val = old_val | mask;

    33     if (new_val == old_val) {

    34       return false;     // Someone else beat us to it.

    35     }

    36     const idx_t cur_val = (idx_t) Atomic::cmpxchg_ptr((void*) new_val,

    37                                                       (volatile void*) addr,

    38                                                       (void*) old_val);

    39     if (cur_val == old_val) {

    40       return true;      // Success.

    41     }

    42     old_val = cur_val;  // The value changed, try again.

    43   } while (true);

    44 }

    46 inline bool BitMap::par_clear_bit(idx_t bit) {

    47   verify_index(bit);

    48   volatile idx_t* const addr = word_addr(bit);

    49   const idx_t mask = ~bit_mask(bit);

    50   idx_t old_val = *addr;

    52   do {

    53     const idx_t new_val = old_val & mask;

    54     if (new_val == old_val) {

    55       return false;     // Someone else beat us to it.

    56     }

    57     const idx_t cur_val = (idx_t) Atomic::cmpxchg_ptr((void*) new_val,

    58                                                       (volatile void*) addr,

    59                                                       (void*) old_val);

    60     if (cur_val == old_val) {

    61       return true;      // Success.

    62     }

    63     old_val = cur_val;  // The value changed, try again.

    64   } while (true);

    65 }

    67 inline BitMap::idx_t

    68 BitMap::find_next_one_bit(idx_t beg_bit, idx_t end_bit) const

    69 {

    70   verify_range(beg_bit, end_bit);

    71   assert(bit_in_word(end_bit) == 0, "end_bit not word-aligned");

    73   if (beg_bit == end_bit) {

    74     return beg_bit;

    75   }

    77   idx_t   index = word_index(beg_bit);

    78   idx_t r_index = word_index(end_bit);

    79   idx_t res_bit = beg_bit;

    81   // check bits including and to the _left_ of offset's position

    82   idx_t res = map(index) >> bit_in_word(res_bit);

    83   if (res != (uintptr_t) NoBits) {

    84     // find the position of the 1-bit

    85     for (; !(res & 1); res_bit++) {

    86       res = res >> 1;

    87     }

    88     assert(res_bit >= beg_bit && res_bit < end_bit, "just checking");

    89     return res_bit;

    90   }

    91   // skip over all word length 0-bit runs

    92   for (index++; index < r_index; index++) {

    93     res = map(index);

    94     if (res != (uintptr_t) NoBits) {

    95       // found a 1, return the offset

    96       for (res_bit = bit_index(index); !(res & 1); res_bit++) {

    97         res = res >> 1;

    98       }

    99       assert(res & 1, "tautology; see loop condition");

   100       assert(res_bit >= beg_bit && res_bit < end_bit, "just checking");

   101       return res_bit;

   102     }

   103   }

   104   return end_bit;

   105 }

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