mem: Make cache terminology easier to understand

This patch changes the name of a bunch of packet flags and MSHR member
functions and variables to make the coherency protocol easier to
understand. In addition the patch adds and updates lots of
descriptions, explicitly spelling out assumptions.

The following name changes are made:

* the packet memInhibit flag is renamed to cacheResponding

* the packet sharedAsserted flag is renamed to hasSharers

* the packet NeedsExclusive attribute is renamed to NeedsWritable

* the packet isSupplyExclusive is renamed responderHadWritable

* the MSHR pendingDirty is renamed to pendingModified

The cache states, Modified, Owned, Exclusive, Shared are also called
out in the cache and MSHR code to make it easier to understand.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/mem/simple_mem.cc b/src/mem/simple_mem.cc
index d4dbe1946..8760c2bef 100644
--- a/src/mem/simple_mem.cc
+++ b/src/mem/simple_mem.cc
@@ -73,7 +73,7 @@ Tick
 SimpleMemory::recvAtomic(PacketPtr pkt)
 {
     access(pkt);
-    return pkt->memInhibitAsserted() ? 0 : getLatency();
+    return pkt->cacheResponding() ? 0 : getLatency();
 }
 
 void
@@ -97,8 +97,8 @@ SimpleMemory::recvFunctional(PacketPtr pkt)
 bool
 SimpleMemory::recvTimingReq(PacketPtr pkt)
 {
-    // sink inhibited packets without further action
-    if (pkt->memInhibitAsserted()) {
+    // if a cache is responding, sink the packet without further action
+    if (pkt->cacheResponding()) {
         pendingDelete.reset(pkt);
         return true;
     }