From 6d120b7912e554aaa44e28d1133f4bbfd9d04f66 Mon Sep 17 00:00:00 2001 From: Kevin Lim Date: Wed, 12 Jul 2006 15:24:27 -0400 Subject: Track the PC of the cache data stored in fetch so it doesn't access memory multiple times if information is already in fetch. --HG-- extra : convert_revision : 00b160b255e998cf99286bcc21894110c7642624 --- src/cpu/o3/fetch.hh | 3 +++ src/cpu/o3/fetch_impl.hh | 7 +++++++ 2 files changed, 10 insertions(+) (limited to 'src/cpu') diff --git a/src/cpu/o3/fetch.hh b/src/cpu/o3/fetch.hh index 85654cebc..0331cf07f 100644 --- a/src/cpu/o3/fetch.hh +++ b/src/cpu/o3/fetch.hh @@ -404,6 +404,9 @@ class DefaultFetch /** The cache line being fetched. */ uint8_t *cacheData[Impl::MaxThreads]; + /** The PC of the cacheline that has been loaded. */ + Addr cacheDataPC[Impl::MaxThreads]; + /** Size of instructions. */ int instSize; diff --git a/src/cpu/o3/fetch_impl.hh b/src/cpu/o3/fetch_impl.hh index de883b5ba..a430f4472 100644 --- a/src/cpu/o3/fetch_impl.hh +++ b/src/cpu/o3/fetch_impl.hh @@ -517,6 +517,11 @@ DefaultFetch::fetchCacheLine(Addr fetch_PC, Fault &ret_fault, unsigned tid // Align the fetch PC so it's at the start of a cache block. fetch_PC = icacheBlockAlignPC(fetch_PC); + // If we've already got the block, no need to try to fetch it again. + if (fetch_PC == cacheDataPC[tid]) { + return true; + } + // Setup the memReq to do a read of the first instruction's address. // Set the appropriate read size and flags as well. // Build request here. @@ -550,6 +555,8 @@ DefaultFetch::fetchCacheLine(Addr fetch_PC, Fault &ret_fault, unsigned tid Packet::ReadReq, Packet::Broadcast); data_pkt->dataStatic(cacheData[tid]); + cacheDataPC[tid] = fetch_PC; + DPRINTF(Fetch, "Fetch: Doing instruction read.\n"); fetchedCacheLines++; -- cgit v1.2.3