ws: fix RTC cartridge protocol emulation

Author: asiekierka

ares/ws/cartridge/cartridge.hpp

@@ -93,6 +93,7 @@ struct Cartridge : IO, Thread {
 
     n4 command;
     n1 active;
+    n1 ready;
     n4 index;
     n8 fetchedData;
     n15 counter;

ares/ws/cartridge/rtc.cpp

@@ -95,20 +95,11 @@ auto Cartridge::RTC::controlRead() -> n8 {
   n8 data = 0;
   data.bit(0,3) = command;
   data.bit(4)   = active;
-  data.bit(7)   = 1;  //0 = busy; 1 = ready for command
+  data.bit(7)   = ready;
   return data;
 }
 
 auto Cartridge::RTC::controlWrite(n5 data) -> void {
-  // TODO: This probably isn't right, but will do unless someone tries to
-  // cancel an RTC command mid-execution.
-  if(active) {
-    if(!data.bit(4) || command != data.bit(0,3)) {
-      debug(unimplemented, "[RTC] Port 0xCA write during command processing = ", data);
-    }
-    return;
-  }
-
   command = data.bit(0,3);
   active = data.bit(4);
 
@@ -132,12 +123,11 @@ auto Cartridge::RTC::controlWrite(n5 data) -> void {
     case 0x0A: { // no-op
       index = 0;
     } break;
-    default: {
-      active = 0;
-    } break;
   }
 
-  if(active && command.bit(0)) fetch();
+  ready = 1;
+  if(active &&  command.bit(0)) fetch();
+  if(active && !command.bit(0)) write(fetchedData);
 }
 
 auto Cartridge::RTC::fetch() -> void {
@@ -181,22 +171,25 @@ auto Cartridge::RTC::fetch() -> void {
       data = 0xFF;
       if(++index >= 2) active = 0;
     } break;
-    default: {
-      active = 0;
-    } break;
   }
 
+  ready = 1;
   fetchedData = data;
 }
 
 auto Cartridge::RTC::read() -> n8 {
   n8 data = fetchedData;
+
+  if(!active) ready = 0;
   if(active && command.bit(0)) fetch();
 
   return data;
 }
 
 auto Cartridge::RTC::write(n8 data) -> void {
+  fetchedData = data;
+
+  if(!active) ready = 0;
   if(active && !command.bit(0)) switch(command & 0x0E) {
     case 0x02: { // STATUS
       status().bit(6) = data.bit(6);
@@ -259,6 +252,7 @@ auto Cartridge::RTC::power() -> void {
 
   command = 0;
   active = 0;
+  ready = 0;
   index = 0;
   counter = 0;
   fetchedData = 0xFF;

ares/ws/cartridge/serialization.cpp

@@ -41,6 +41,7 @@ auto Cartridge::RTC::serialize(serializer& s) -> void {
 
   s(command);
   s(active);
+  s(ready);
   s(index);
   s(fetchedData);
   s(counter);

ares/ws/system/serialization.cpp

@@ -1,4 +1,4 @@
-static const string SerializerVersion = "v144.2";
+static const string SerializerVersion = "v144.3";
 
 auto System::serialize(bool synchronize) -> serializer {
   if(synchronize) scheduler.enter(Scheduler::Mode::Synchronize);