+ if (mvar->head != (StgTSO *)&stg_END_TSO_QUEUE_closure) {
+ /* There are putMVar(s) waiting...
+ * wake up the first thread on the queue
+ */
+ ASSERT(mvar->head->why_blocked == BlockedOnMVar);
+
+ /* actually perform the putMVar for the thread that we just woke up */
+ mvar->value = PerformPut(mvar->head);
+
+#if defined(GRAN) || defined(PAR)
+ /* ToDo: check 2nd arg (mvar) is right */
+ mvar->head = RET_STGCALL2(StgTSO *,unblockOne,mvar->head,mvar);
+#else
+ mvar->head = RET_STGCALL1(StgTSO *,unblockOne,mvar->head);
+#endif
+ if (mvar->head == (StgTSO *)&stg_END_TSO_QUEUE_closure) {
+ mvar->tail = (StgTSO *)&stg_END_TSO_QUEUE_closure;
+ }
+#ifdef SMP
+ /* unlock in the SMP case */
+ SET_INFO(mvar,&stg_FULL_MVAR_info);
+#endif
+ TICK_RET_UNBOXED_TUP(1);
+ RET_P(val);
+ } else {
+ /* No further putMVars, MVar is now empty */
+
+ /* do this last... we might have locked the MVar in the SMP case,
+ * and writing the info pointer will unlock it.
+ */
+ SET_INFO(mvar,&stg_EMPTY_MVAR_info);
+ mvar->value = (StgClosure *)&stg_END_TSO_QUEUE_closure;
+ TICK_RET_UNBOXED_TUP(1);
+ RET_P(val);
+ }
+ FE_
+}
+
+FN_(tryTakeMVarzh_fast)
+{
+ StgMVar *mvar;
+ StgClosure *val;
+ const StgInfoTable *info;
+
+ FB_
+ /* args: R1 = MVar closure */
+
+ mvar = (StgMVar *)R1.p;
+
+#ifdef SMP
+ info = LOCK_CLOSURE(mvar);
+#else
+ info = GET_INFO(mvar);
+#endif
+
+ if (info == &stg_EMPTY_MVAR_info) {
+
+#ifdef SMP
+ /* unlock the MVar */
+ SET_INFO(mvar,&stg_EMPTY_MVAR_info);
+#endif
+
+ /* HACK: we need a pointer to pass back,
+ * so we abuse NO_FINALIZER_closure
+ */
+ RET_NP(0, &stg_NO_FINALIZER_closure);
+ }
+
+ /* we got the value... */
+ val = mvar->value;
+
+ if (mvar->head != (StgTSO *)&stg_END_TSO_QUEUE_closure) {
+ /* There are putMVar(s) waiting...
+ * wake up the first thread on the queue
+ */
+ ASSERT(mvar->head->why_blocked == BlockedOnMVar);
+
+ /* actually perform the putMVar for the thread that we just woke up */
+ mvar->value = PerformPut(mvar->head);
+
+#if defined(GRAN) || defined(PAR)
+ /* ToDo: check 2nd arg (mvar) is right */
+ mvar->head = RET_STGCALL2(StgTSO *,unblockOne,mvar->head,mvar);
+#else
+ mvar->head = RET_STGCALL1(StgTSO *,unblockOne,mvar->head);
+#endif
+ if (mvar->head == (StgTSO *)&stg_END_TSO_QUEUE_closure) {
+ mvar->tail = (StgTSO *)&stg_END_TSO_QUEUE_closure;
+ }
+#ifdef SMP
+ /* unlock in the SMP case */
+ SET_INFO(mvar,&stg_FULL_MVAR_info);
+#endif
+ } else {
+ /* No further putMVars, MVar is now empty */
+ mvar->value = (StgClosure *)&stg_END_TSO_QUEUE_closure;
+
+ /* do this last... we might have locked the MVar in the SMP case,
+ * and writing the info pointer will unlock it.
+ */
+ SET_INFO(mvar,&stg_EMPTY_MVAR_info);
+ }