1 /* Copyright (c) 2014-2022. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #ifndef SIMGRID_MC_MMU_HPP
7 #define SIMGRID_MC_MMU_HPP
12 #ifndef XBT_ALWAYS_INLINE
13 #define XBT_ALWAYS_INLINE inline __attribute__((always_inline))
16 /** Size of a memory page for the current system. */
17 extern "C" int xbt_pagesize;
18 /** Number of bits of addresses inside a given page, log2(xbt_pagesize). */
19 extern "C" int xbt_pagebits;
21 namespace simgrid::mc::mmu {
22 // TODO, do not depend on xbt_pagesize/xbt_pagebits but our own chunk size
24 /** @brief How many memory pages are necessary to store size bytes?
26 * @param size Byte size
27 * @return Number of memory pages
29 static XBT_ALWAYS_INLINE std::size_t chunk_count(std::size_t size)
31 std::size_t page_count = size >> xbt_pagebits;
32 if (size & (xbt_pagesize - 1))
37 /** @brief Split into chunk number and remaining offset */
38 static XBT_ALWAYS_INLINE std::pair<std::size_t, std::uintptr_t> split(std::uintptr_t offset)
40 return {offset >> xbt_pagebits, offset & (xbt_pagesize - 1)};
43 /** Merge chunk number and remaining offset into a global offset */
44 static XBT_ALWAYS_INLINE std::uintptr_t join(std::size_t page, std::uintptr_t offset)
46 return ((std::uintptr_t)page << xbt_pagebits) + offset;
49 static XBT_ALWAYS_INLINE std::uintptr_t join(std::pair<std::size_t, std::uintptr_t> value)
51 return join(value.first, value.second);
54 static XBT_ALWAYS_INLINE bool same_chunk(std::uintptr_t a, std::uintptr_t b)
56 return (a >> xbt_pagebits) == (b >> xbt_pagebits);
58 } // namespace simgrid::mc::mmu