1 /* Copyright (C) 2009-2013 Free Software Foundation, Inc. 2 Contributed by Richard Henderson <rth@redhat.com>. 3 4 This file is part of the GNU Transactional Memory Library (libitm). 5 6 Libitm is free software; you can redistribute it and/or modify it 7 under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3 of the License, or 9 (at your option) any later version. 10 11 Libitm is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 13 FOR A PARTICULAR PURPOSE. See the GNU General Public License for 14 more details. 15 16 Under Section 7 of GPL version 3, you are granted additional 17 permissions described in the GCC Runtime Library Exception, version 18 3.1, as published by the Free Software Foundation. 19 20 You should have received a copy of the GNU General Public License and 21 a copy of the GCC Runtime Library Exception along with this program; 22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 <http://www.gnu.org/licenses/>. */ 24 25 #ifndef LIBITM_CACHELINE_H 26 #define LIBITM_CACHELINE_H 1 27 28 namespace GTM HIDDEN { 29 30 // A cacheline is the smallest unit with which locks are associated. 31 // The current implementation of the _ITM_[RW] barriers assumes that 32 // all data types can fit (aligned) within a cachline, which means 33 // in practice sizeof(complex long double) is the smallest cacheline size. 34 // It ought to be small enough for efficient manipulation of the 35 // modification mask, below. 36 #ifndef CACHELINE_SIZE 37 # define CACHELINE_SIZE 32 38 #endif 39 40 // A gtm_cacheline_mask stores a modified bit for every modified byte 41 // in the cacheline with which it is associated. 42 typedef sized_integral<CACHELINE_SIZE / 8>::type gtm_cacheline_mask; 43 44 union gtm_cacheline 45 { 46 // Byte access to the cacheline. 47 unsigned char b[CACHELINE_SIZE] __attribute__((aligned(CACHELINE_SIZE))); 48 49 // Larger sized access to the cacheline. 50 uint16_t u16[CACHELINE_SIZE / sizeof(uint16_t)]; 51 uint32_t u32[CACHELINE_SIZE / sizeof(uint32_t)]; 52 uint64_t u64[CACHELINE_SIZE / sizeof(uint64_t)]; 53 gtm_word w[CACHELINE_SIZE / sizeof(gtm_word)]; 54 }; 55 56 } // namespace GTM 57 58 #endif // LIBITM_CACHELINE_H 59