systemc: Implement the nonstandard halt function.

Change-Id: Ie9bd9db92a63169980230bc9a15e153d5609dd0b
Reviewed-on: https://gem5-review.googlesource.com/c/12594
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/core/process.cc

@@ -338,6 +338,8 @@ Process::run()
         reset = false;
         try {
             func->call();
+        } catch(ScHalt) {
+            std::cout << "Terminating process " << name() << std::endl;
         } catch(const ::sc_core::sc_unwind_exception &exc) {
             reset = exc.is_reset();
             _isUnwinding = false;

src/systemc/core/process.hh

@@ -52,6 +52,9 @@
 namespace sc_gem5
 {
 
+class ScHalt
+{};
+
 class Sensitivity
 {
   protected:

src/systemc/core/sc_module.cc

@@ -670,7 +670,8 @@ wait(double d, sc_time_unit u, const sc_event_and_list &eal)
 void
 halt()
 {
-    warn("%s not implemented.\n", __PRETTY_FUNCTION__);
+    ::sc_core::wait();
+    throw ::sc_gem5::ScHalt();
 }
 
 void