mem: Rework the structuring of the prefetchers

Re-organizes the prefetcher class structure. Previously the
BasePrefetcher forced multiple assumptions on the prefetchers that
inherited from it. This patch makes the BasePrefetcher class truly
representative of base functionality. For example, the base class no
longer enforces FIFO order. Instead, prefetchers with FIFO requests
(like the existing stride and tagged prefetchers) now inherit from a
new QueuedPrefetcher base class.

Finally, the stride-based prefetcher now assumes a custimizable lookup table
(sets/ways) rather than the previous fully associative structure.

1 files changed, 7 insertions, 9 deletions

diff --git a/src/mem/cache/prefetch/tagged.cc b/src/mem/cache/prefetch/tagged.cc
index f34b28b14..59c489a28 100644
--- a/src/mem/cache/prefetch/tagged.cc
+++ b/src/mem/cache/prefetch/tagged.cc
@@ -35,32 +35,30 @@
 
 #include "mem/cache/prefetch/tagged.hh"
 
-TaggedPrefetcher::TaggedPrefetcher(const Params *p)
-    : BasePrefetcher(p)
+TaggedPrefetcher::TaggedPrefetcher(const TaggedPrefetcherParams *p)
+    : QueuedPrefetcher(p), degree(p->degree)
 {
+
 }
 
 void
-TaggedPrefetcher::
-calculatePrefetch(PacketPtr &pkt, std::list<Addr> &addresses,
-                  std::list<Cycles> &delays)
+TaggedPrefetcher::calculatePrefetch(const PacketPtr &pkt,
+        std::vector<Addr> &addresses)
 {
     Addr blkAddr = pkt->getAddr() & ~(Addr)(blkSize-1);
 
     for (int d = 1; d <= degree; d++) {
         Addr newAddr = blkAddr + d*(blkSize);
-        if (pageStop &&  !samePage(blkAddr, newAddr)) {
-            // Spanned the page, so now stop
+        if (!samePage(blkAddr, newAddr)) {
+            // Count number of unissued prefetches due to page crossing
             pfSpanPage += degree - d + 1;
             return;
         } else {
             addresses.push_back(newAddr);
-            delays.push_back(latency);
         }
     }
 }
 
-
 TaggedPrefetcher*
 TaggedPrefetcherParams::create()
 {