ARM/Alpha/Cpu: Change prefetchs to be more like normal loads.

This change modifies the way prefetches work. They are now like normal loads
that don't writeback a register. Previously prefetches were supposed to call
prefetch() on the exection context, so they executed with execute() methods
instead of initiateAcc() completeAcc(). The prefetch() methods for all the CPUs
are blank, meaning that they get executed, but don't actually do anything.

On Alpha dead cache copy code was removed and prefetches are now normal ops.
They count as executed operations, but still don't do anything and IsMemRef is
not longer set on them.

On ARM IsDataPrefetch or IsInstructionPreftech is now set on all prefetch
instructions. The timing simple CPU doesn't try to do anything special for
prefetches now and they execute with the normal memory code path.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/cpu/static_inst.hh b/src/cpu/static_inst.hh
index 5951ab122..e08cbcdb6 100644
--- a/src/cpu/static_inst.hh
+++ b/src/cpu/static_inst.hh
@@ -226,6 +226,8 @@ class StaticInstBase : public RefCounted
     bool isStoreConditional()     const { return flags[IsStoreConditional]; }
     bool isInstPrefetch() const { return flags[IsInstPrefetch]; }
     bool isDataPrefetch() const { return flags[IsDataPrefetch]; }
+    bool isPrefetch()     const { return isInstPrefetch() ||
+                                         isDataPrefetch(); }
     bool isCopy()         const { return flags[IsCopy];}
 
     bool isInteger()      const { return flags[IsInteger]; }