systemc: Implement the sc_*_resolved classes.

Change-Id: Ib595da10e0f900ee4cc1847d41d29251dacb55d7
Reviewed-on: https://gem5-review.googlesource.com/c/12620
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

1 files changed, 35 insertions, 14 deletions

diff --git a/src/systemc/channel/sc_signal_resolved.cc b/src/systemc/channel/sc_signal_resolved.cc
index 90431842e..119082486 100644
--- a/src/systemc/channel/sc_signal_resolved.cc
+++ b/src/systemc/channel/sc_signal_resolved.cc
@@ -28,6 +28,8 @@
  */
 
 #include "base/logging.hh"
+#include "systemc/core/process.hh"
+#include "systemc/core/scheduler.hh"
 #include "systemc/ext/channel/sc_signal_resolved.hh"
 #include "systemc/ext/core/sc_module.hh" // for sc_gen_unique_name
 
@@ -44,39 +46,58 @@ sc_signal_resolved::sc_signal_resolved(const char *name) :
 {}
 
 sc_signal_resolved::~sc_signal_resolved() {}
+void sc_signal_resolved::register_port(sc_port_base &, const char *) {}
 
 void
-sc_signal_resolved::register_port(sc_port_base &, const char *)
+sc_signal_resolved::write(const sc_dt::sc_logic &l)
 {
-    warn("%s not implemented.\n", __PRETTY_FUNCTION__);
-}
+    ::sc_gem5::Process *p = ::sc_gem5::scheduler.current();
 
-void
-sc_signal_resolved::write(const sc_dt::sc_logic &)
-{
-    warn("%s not implemented.\n", __PRETTY_FUNCTION__);
+    auto it = inputs.find(p);
+    if (it == inputs.end()) {
+        inputs.emplace(p, l);
+        request_update();
+    } else if (it->second != l) {
+        it->second = l;
+        request_update();
+    }
 }
 
 sc_signal_resolved &
-sc_signal_resolved::operator = (const sc_dt::sc_logic &)
+sc_signal_resolved::operator = (const sc_dt::sc_logic &l)
 {
-    warn("%s not implemented.\n", __PRETTY_FUNCTION__);
+    write(l);
     return *this;
 }
 
 sc_signal_resolved &
-sc_signal_resolved::operator = (const sc_signal_resolved &)
+sc_signal_resolved::operator = (const sc_signal_resolved &r)
 {
-    warn("%s not implemented.\n", __PRETTY_FUNCTION__);
+    write(r.read());
     return *this;
 }
 
-const char *sc_signal_resolved::kind() const { return "sc_signal_resolved"; }
-
 void
 sc_signal_resolved::update()
 {
-    warn("%s not implemented.\n", __PRETTY_FUNCTION__);
+    using sc_dt::Log_0;
+    using sc_dt::Log_1;
+    using sc_dt::Log_Z;
+    using sc_dt::Log_X;
+    static sc_dt::sc_logic_value_t merge_table[4][4] = {
+        { Log_0, Log_X, Log_0, Log_X },
+        { Log_X, Log_1, Log_1, Log_X },
+        { Log_0, Log_1, Log_Z, Log_X },
+        { Log_X, Log_X, Log_X, Log_X }
+    };
+
+    // Resolve the inputs, and give the result to the underlying signal class.
+    m_new_val = Log_Z;
+    for (auto &input: inputs)
+        m_new_val = merge_table[m_new_val.value()][input.second.value()];
+
+    // Ask the signal to update it's value.
+    sc_signal<sc_dt::sc_logic, SC_MANY_WRITERS>::update();
 }
 
 } // namespace sc_core