mem: Use the range cache for lookup as well as access

This patch changes the range cache used in the global physical memory
to be an iterator so that we can use it not only as part of isMemAddr,
but also access and functionalAccess. This matches use-cases where a
core is using the atomic non-caching memory mode, and repeatedly calls
isMemAddr and access.

Linux boot on aarch32, with a single atomic CPU, is now more than 30%
faster when using "--fastmem" compared to not using the direct memory
access.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/mem/physical.hh b/src/mem/physical.hh
index 51ec1cbd3..b8d26fd4b 100644
--- a/src/mem/physical.hh
+++ b/src/mem/physical.hh
@@ -75,8 +75,9 @@ class PhysicalMemory : public Serializable
     // Global address map
     AddrRangeMap<AbstractMemory*> addrMap;
 
-    // a mutable cache for the last range that matched an address
-    mutable AddrRange rangeCache;
+    // a mutable cache for the last address map iterator that matched
+    // an address
+    mutable AddrRangeMap<AbstractMemory*>::const_iterator rangeCache;
 
     // All address-mapped memories
     std::vector<AbstractMemory*> memories;