Move store conditional result checking from SimpleAtomicCpu write

function into Alpha ISA description.  write now just generically
returns a result value if the res pointer is non-null (which means
we can only provide a res pointer if we expect a valid result
value).

--HG--
extra : convert_revision : fb1c315515787f5fbbf7d1af7e428bdbfe8148b8

src/cpu/simple/atomic.cc

@@ -401,15 +401,8 @@ AtomicSimpleCPU::write(T data, Addr addr, unsigned flags, uint64_t *res)
 #endif
         }
 
-        if (req->isLocked()) {
-            uint64_t scResult = req->getScResult();
-            if (scResult != 0) {
-                // clear failure counter
-                thread->setStCondFailures(0);
-            }
-            if (res) {
-                *res = req->getScResult();
-            }
+        if (res) {
+            *res = req->getScResult();
         }
     }
 

src/cpu/simple/base.hh

@@ -329,6 +329,14 @@ class BaseSimpleCPU : public BaseCPU
         return thread->setMiscRegWithEffect(reg_idx, val);
     }
 
+    unsigned readStCondFailures() {
+        return thread->readStCondFailures();
+    }
+
+    void setStCondFailures(unsigned sc_failures) {
+        thread->setStCondFailures(sc_failures);
+    }
+
 #if FULL_SYSTEM
     Fault hwrei() { return thread->hwrei(); }
     void ev5_trap(Fault fault) { fault->invoke(tc); }