1 /* 2 * Copyright (c) 2017, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 #ifndef SHARE_GC_Z_ZPAGETABLEENTRY_HPP 25 #define SHARE_GC_Z_ZPAGETABLEENTRY_HPP 26 27 #include "gc/z/zBitField.hpp" 28 #include "memory/allocation.hpp" 29 30 // 31 // Page table entry layout 32 // ----------------------- 33 // 34 // 6 35 // 3 1 0 36 // +----------------------------------------------------------------------+-+ 37 // |11111111 11111111 11111111 11111111 11111111 11111111 11111111 1111111|1| 38 // +----------------------------------------------------------------------+-+ 39 // | | 40 // | 0-0 Relocating Flag (1-bit) * 41 // | 42 // | 43 // | 44 // * 63-1 Page address (63-bits) 45 // 46 47 class ZPage; 48 49 class ZPageTableEntry VALUE_OBJ_CLASS_SPEC { 50 private: 51 typedef ZBitField<uint64_t, bool, 0, 1> field_relocating; 52 typedef ZBitField<uint64_t, ZPage*, 1, 63, 1> field_page; 53 54 uint64_t _entry; 55 56 public: 57 ZPageTableEntry() : 58 _entry(0) {} 59 60 ZPageTableEntry(ZPage* page, bool relocating) : 61 _entry(field_page::encode(page) | 62 field_relocating::encode(relocating)) {} 63 64 bool relocating() const { 65 return field_relocating::decode(_entry); 66 } 67 68 ZPage* page() const { 69 return field_page::decode(_entry); 70 } 71 }; 72 73 #endif // SHARE_GC_Z_ZPAGETABLEENTRY_HPP