Mercurial > hg > truffle
comparison src/share/vm/utilities/bitMap.inline.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | 37f87013dfd8 |
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-1:000000000000 | 0:a61af66fc99e |
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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 */ | |
24 | |
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; | |
30 | |
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 } | |
45 | |
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; | |
51 | |
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 } | |
66 | |
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"); | |
72 | |
73 if (beg_bit == end_bit) { | |
74 return beg_bit; | |
75 } | |
76 | |
77 idx_t index = word_index(beg_bit); | |
78 idx_t r_index = word_index(end_bit); | |
79 idx_t res_bit = beg_bit; | |
80 | |
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 } |