[mc] Better documentation of AddressSpace

[simgrid.git] / src / mc / mc_mmu.h

diff --git a/src/mc/mc_mmu.h b/src/mc/mc_mmu.h
index e0236e5..1438db4 100644 (file)
--- a/src/mc/mc_mmu.h
+++ b/src/mc/mc_mmu.h
@@ -8,13 +8,24 @@
 #define SIMGRID_MC_MMU_H
 
 #include <cstdint>
+#include <cstddef>
 
 #include <xbt/asserts.h>
+#include <xbt/base.h> // xbt_pagesize...
 #include <xbt/misc.h>
 
 #include <simgrid_config.h>
 
-SG_BEGIN_DECL()
+
+namespace simgrid {
+namespace mc {
+// TODO, do not depend on xbt_pagesize/xbt_pagebits but our own chunk size
+namespace mmu {
+
+static int chunkSize()
+{
+  return xbt_pagesize;
+}
 
 /** @brief How many memory pages are necessary to store size bytes?
  *
@@ -22,56 +33,45 @@ SG_BEGIN_DECL()
  *  @return Number of memory pages
  */
 static inline __attribute__ ((always_inline))
-size_t mc_page_count(size_t size)
+std::size_t chunkCount(std::size_t size)
 {
   size_t page_count = size >> xbt_pagebits;
-  if (size & (xbt_pagesize-1)) {
+  if (size & (xbt_pagesize-1))
     page_count ++;
-  }
   return page_count;
 }
 
-/** @brief Get the virtual memory page number of a given address
- *
- *  @param address Address
- *  @return Virtual memory page number of the given address
- */
+/** @brief Split into chunk number and remaining offset */
 static inline __attribute__ ((always_inline))
-size_t mc_page_number(const void* base, const void* address)
+std::pair<std::size_t, std::uintptr_t> split(std::uintptr_t offset)
 {
-  xbt_assert(address>=base, "The address is not in the range");
-  return ((std::uintptr_t) address - (std::uintptr_t) base) >> xbt_pagebits;
+  return {
+    offset >> xbt_pagebits,
+    offset & (xbt_pagesize-1)
+  };
 }
 
-/** @brief Get the offset of an address within a memory page
- *
- *  @param address Address
- *  @return Offset within the memory page
- */
+/** Merge chunk number and remaining offset info a global offset */
 static inline __attribute__ ((always_inline))
-size_t mc_page_offset(const void* address)
+std::uintptr_t join(std::size_t page, std::uintptr_t offset)
 {
-  return ((std::uintptr_t) address) & (xbt_pagesize-1);
+  return ((std::uintptr_t) page << xbt_pagebits) + offset;
 }
 
-/** @brief Get the virtual address of a virtual memory page
- *
- *  @param base Address of the first page
- *  @param page Index of the page
- */
 static inline __attribute__ ((always_inline))
-void* mc_page_from_number(const void* base, size_t page)
+std::uintptr_t join(std::pair<std::size_t,std::uintptr_t> value)
 {
-  return (void*) ((char*)base + (page << xbt_pagebits));
+  return join(value.first, value.second);
 }
 
 static inline __attribute__ ((always_inline))
-bool mc_same_page(const void* a, const void* b)
+bool sameChunk(std::uintptr_t a, std::uintptr_t b)
 {
-  return ((std::uintptr_t) a >> xbt_pagebits)
-    == ((std::uintptr_t) b >> xbt_pagebits);
+  return (a >> xbt_pagebits) == (b >> xbt_pagebits);
 }
 
-SG_END_DECL()
+}
+}
+}
 
 #endif