Fixes to get prefetching working again.

Apparently we broke it with the cache rewrite and never noticed.
Thanks to Bao Yungang <baoyungang@gmail.com> for a significant part
of these changes (and for inspiring me to work on the rest).
Some other overdue cleanup on the prefetch code too.

1 files changed, 14 insertions, 21 deletions

diff --git a/src/mem/cache/prefetch/ghb.cc b/src/mem/cache/prefetch/ghb.cc
index c8b87e99d..c27165248 100644
--- a/src/mem/cache/prefetch/ghb.cc
+++ b/src/mem/cache/prefetch/ghb.cc
@@ -41,32 +41,25 @@ void
 GHBPrefetcher::calculatePrefetch(PacketPtr &pkt, std::list<Addr> &addresses,
                                  std::list<Tick> &delays)
 {
-    Addr blkAddr = pkt->getAddr() & ~(Addr)(this->blkSize-1);
-    int contextId = pkt->req->contextId();
-    if (!useContextId) contextId = 0;
+    Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize-1);
+    int ctx_id = useContextId ? pkt->req->contextId() : 0;
+    assert(ctx_id < Max_Contexts);
 
+    int new_stride = blk_addr - lastMissAddr[ctx_id];
+    int old_stride = lastMissAddr[ctx_id] - secondLastMissAddr[ctx_id];
 
-    int new_stride = blkAddr - last_miss_addr[contextId];
-    int old_stride = last_miss_addr[contextId] -
-        second_last_miss_addr[contextId];
-
-    second_last_miss_addr[contextId] = last_miss_addr[contextId];
-    last_miss_addr[contextId] = blkAddr;
+    secondLastMissAddr[ctx_id] = lastMissAddr[ctx_id];
+    lastMissAddr[ctx_id] = blk_addr;
 
     if (new_stride == old_stride) {
-        for (int d=1; d <= degree; d++) {
-            Addr newAddr = blkAddr + d * new_stride;
-            if (this->pageStop &&
-                (blkAddr & ~(TheISA::VMPageSize - 1)) !=
-                (newAddr & ~(TheISA::VMPageSize - 1)))
-            {
-                //Spanned the page, so now stop
-                this->pfSpanPage += degree - d + 1;
+        for (int d = 1; d <= degree; d++) {
+            Addr new_addr = blk_addr + d * new_stride;
+            if (pageStop && !samePage(blk_addr, new_addr)) {
+                // Spanned the page, so now stop
+                pfSpanPage += degree - d + 1;
                 return;
-            }
-            else
-            {
-                addresses.push_back(newAddr);
+            } else {
+                addresses.push_back(new_addr);
                 delays.push_back(latency);
             }
         }