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, 4 deletions

diff --git a/src/mem/addr_mapper.cc b/src/mem/addr_mapper.cc
index 2f0020576..546dd6906 100644
--- a/src/mem/addr_mapper.cc
+++ b/src/mem/addr_mapper.cc
@@ -116,16 +116,15 @@ AddrMapper::recvTimingReq(PacketPtr pkt)
 {
     Addr orig_addr = pkt->getAddr();
     bool needsResponse = pkt->needsResponse();
-    bool memInhibitAsserted = pkt->memInhibitAsserted();
+    bool cacheResponding = pkt->cacheResponding();
 
-    if (needsResponse && !memInhibitAsserted) {
+    if (needsResponse && !cacheResponding) {
         pkt->pushSenderState(new AddrMapperSenderState(orig_addr));
     }
 
     pkt->setAddr(remapAddr(orig_addr));
 
-    // Attempt to send the packet (always succeeds for inhibited
-    // packets)
+    // Attempt to send the packet
     bool successful = masterPort.sendTimingReq(pkt);
 
     // If not successful, restore the address and sender state