diff -r e4f63f1d502d -r b8de61e29ce1 src/mem/snoop_filter.hh
--- a/src/mem/snoop_filter.hh	Sun Jun 21 20:52:13 2015 +0100
+++ b/src/mem/snoop_filter.hh	Thu Jun 25 12:00:53 2015 +0900
@@ -54,6 +54,9 @@
 #include "sim/sim_object.hh"
 #include "sim/system.hh"
 
+#define MAX_CORES 64
+#define MAX_SLAVE_PORTS MAX_CORES*2+1
+
 /**
  * This snoop filter keeps track of which connected port has a
  * particular line of data. It can be queried (through lookup*) on
@@ -191,7 +194,7 @@
     virtual void regStats();
 
   protected:
-    typedef uint64_t SnoopMask;
+    typedef std::bitset<MAX_SLAVE_PORTS> SnoopMask;
    /**
     * Per cache line item tracking a bitmask of SlavePorts who have an
     * outstanding request to this line (requested) or already share a cache line
@@ -219,6 +222,7 @@
      * @return SnoopList containing all the requested SlavePorts
      */
     SnoopList maskToPortList(SnoopMask ports) const;
+    bool isMaskPow2(SnoopMask mask);
 
   private:
     /** Simple hash set of cached addresses. */
@@ -247,7 +251,7 @@
     assert(id != (unsigned)InvalidPortID);
     assert((int)id < 8 * sizeof(SnoopMask));
 
-    return ((SnoopMask)1) << id;
+    return SnoopMask(0).set(id,true);
 }
 
 inline SnoopFilter::SnoopMask
@@ -264,8 +268,17 @@
 {
     SnoopList res;
     for (auto port = slavePorts.begin(); port != slavePorts.end(); ++port)
-        if (port_mask & portToMask(**port))
+        if ((port_mask & portToMask(**port)).any())
             res.push_back(*port);
     return res;
 }
+
+/**
+ * Checks if a number is a power of two, or zero.
+ */
+inline bool
+SnoopFilter::isMaskPow2(SnoopMask v)
+{
+   return v.count() <= 1;
+}
 #endif // __MEM_SNOOP_FILTER_HH__
diff -r e4f63f1d502d -r b8de61e29ce1 src/mem/snoop_filter.cc
--- a/src/mem/snoop_filter.cc	Sun Jun 21 20:52:13 2015 +0100
+++ b/src/mem/snoop_filter.cc	Thu Jun 25 12:00:53 2015 +0900
@@ -65,7 +65,7 @@
     totRequests++;
     if (is_hit) {
         // Single bit set -> value is a power of two
-        if (isPow2(interested))
+        if (isMaskPow2(interested))
             hitSingleRequests++;
         else
             hitMultiRequests++;
@@ -77,7 +77,7 @@
     if (!cpkt->req->isUncacheable() && cpkt->needsResponse()) {
         if (!cpkt->memInhibitAsserted()) {
             // Max one request per address per port
-            panic_if(sf_item.requested & req_port, "double request :( "\
+            panic_if((sf_item.requested & req_port).any(), "double request :( "\
                      "SF value %x.%x\n", sf_item.requested, sf_item.holder);
 
             // Mark in-flight requests to distinguish later on
@@ -87,7 +87,7 @@
             // to the CPU, already -> the response will not be seen by this
             // filter -> we do not need to keep the in-flight request, but make
             // sure that we know that that cluster has a copy
-            panic_if(!(sf_item.holder & req_port), "Need to hold the value!");
+            panic_if((sf_item.holder & req_port).none(), "Need to hold the value!");
             DPRINTF(SnoopFilter, "%s:   not marking request. SF value %x.%x\n",
                     __func__,  sf_item.requested, sf_item.holder);
         }
@@ -126,9 +126,9 @@
         // snoop filter; WRITEBACKs for now only
         if (cpkt->cmd == MemCmd::Writeback) {
             // make sure that the sender actually had the line
-            panic_if(sf_item.requested & req_port, "double request :( "\
+            panic_if((sf_item.requested & req_port).any(), "double request :( "\
                      "SF value %x.%x\n", sf_item.requested, sf_item.holder);
-            panic_if(!(sf_item.holder & req_port), "requester %x is not a "\
+            panic_if((sf_item.holder & req_port).none(), "requester %x is not a "\
                      "holder :( SF value %x.%x\n", req_port,
                      sf_item.requested, sf_item.holder);
             // Writebacks -> the sender does not have the line anymore
@@ -169,14 +169,14 @@
     totSnoops++;
     if (is_hit) {
         // Single bit set -> value is a power of two
-        if (isPow2(interested))
+        if (isMaskPow2(interested))
             hitSingleSnoops++;
         else
             hitMultiSnoops++;
     }
 
     assert(cpkt->isInvalidate() == cpkt->needsExclusive());
-    if (cpkt->isInvalidate() && !sf_item.requested) {
+    if (cpkt->isInvalidate() && sf_item.requested.none()) {
         // Early clear of the holder, if no other request is currently going on
         // @todo: This should possibly be updated even though we do not filter
         // upward snoops
@@ -213,11 +213,11 @@
             __func__,  sf_item.requested, sf_item.holder);
 
     // The source should have the line
-    panic_if(!(sf_item.holder & rsp_mask), "SF value %x.%x does not have "\
+    panic_if((sf_item.holder & rsp_mask).none(), "SF value %x.%x does not have "\
              "the line\n", sf_item.requested, sf_item.holder);
 
     // The destination should have had a request in
-    panic_if(!(sf_item.requested & req_mask), "SF value %x.%x missing "\
+    panic_if((sf_item.requested & req_mask).none(), "SF value %x.%x missing "\
              "the original request\n",  sf_item.requested, sf_item.holder);
 
     // Update the residency of the cache line.
@@ -289,7 +289,7 @@
             __func__,  sf_item.requested, sf_item.holder);
 
     // Make sure we have seen the actual request, too
-    panic_if(!(sf_item.requested & slave_mask), "SF value %x.%x missing "\
+    panic_if((sf_item.requested & slave_mask).none(), "SF value %x.%x missing "\
              "request bit\n", sf_item.requested, sf_item.holder);
 
     // Update the residency of the cache line.