n64: add rtc.cpp and implement rtc timestamp

ares/n64/dd/dd.cpp

@@ -4,6 +4,7 @@ namespace ares::Nintendo64 {
 
 DD dd;
 #include "controller.cpp"
+#include "rtc.cpp"
 #include "io.cpp"
 #include "debugger.cpp"
 #include "serialization.cpp"
@@ -23,7 +24,7 @@ auto DD::load(Node::Object parent) -> void {
   c2s.allocate(0x400);
   ds.allocate(0x100);
   ms.allocate(0x40);
-  rtc.allocate(0x8);
+  rtc.allocate(0x10);
 
   // TODO: Detect correct CIC from ipl rom
   if(auto fp = system.pak->read("64dd.ipl.rom")) {
@@ -60,9 +61,7 @@ auto DD::connect() -> void {
   fd = pak->read("program.disk");
   if(!fd) return disconnect();
 
-  if(auto fp = system.pak->read("time.rtc")) {
-    rtc.load(fp);
-  }
+  rtcLoad();
 }
 
 auto DD::disconnect() -> void {
@@ -73,9 +72,7 @@ auto DD::disconnect() -> void {
 }
 
 auto DD::save() -> void {
-  if(auto fp = system.pak->write("time.rtc")) {
-    rtc.save(fp);
-  }
+  rtcSave();
 }
 
 auto DD::power(bool reset) -> void {

ares/n64/dd/dd.hpp

@@ -46,6 +46,12 @@ struct DD : Memory::IO<DD> {
   //controller.cpp
   auto command(n16 command) -> void;
 
+  //rtc.cpp
+  auto rtcLoad() -> void;
+  auto rtcSave() -> void;
+  auto rtcTick(u32 offset) -> void;
+  auto rtcTickSecond() -> void;
+
   //io.cpp
   auto readWord(u32 address) -> u32;
   auto writeWord(u32 address, u32 data) -> void;

ares/n64/dd/rtc.cpp

@@ -0,0 +1,61 @@
+auto DD::rtcLoad() -> void {
+  if(auto fp = system.pak->read("time.rtc")) {
+    rtc.load(fp);
+  }
+
+  n64 timestamp = 0;
+  for(auto n : range(8)) timestamp.byte(n) = rtc.read<Byte>(8 + n);
+  if(!~timestamp) return;  //new save file
+
+  timestamp = time(0) - timestamp;
+  while(timestamp--) rtcTickSecond();
+}
+
+auto DD::rtcSave() -> void {
+  n64 timestamp = time(0);
+  for(auto n : range(8)) rtc.write<Byte>(8 + n, timestamp.byte(n));
+
+  if(auto fp = system.pak->write("time.rtc")) {
+    rtc.save(fp);
+  }
+}
+
+auto DD::rtcTick(u32 offset) -> void {
+  u8 n = rtc.read<Byte>(offset);
+  if((++n & 0xf) > 9) n = (n & 0xf0) + 0x10;
+  if((n & 0xf0) > 0x90) n = 0;
+  rtc.write<Byte>(offset, n);
+}
+
+auto DD::rtcTickSecond() -> void {
+  //second
+  rtcTick(5);
+  if(rtc.read<Byte>(5) < 0x60) return;
+  rtc.write<Byte>(5, 0);
+
+  //minute
+  rtcTick(4);
+  if(rtc.read<Byte>(4) < 0x60) return;
+  rtc.write<Byte>(4, 0);
+
+  //hour
+  rtcTick(3);
+  if(rtc.read<Byte>(3) < 0x24) return;
+  rtc.write<Byte>(3, 0);
+
+  //day
+  u32 daysInMonth[12] = {0x31, 0x28, 0x31, 0x30, 0x31, 0x30, 0x31, 0x31, 0x30, 0x31, 0x30, 0x31};
+  if(rtc.read<Byte>(0) && !(BCD::decode(rtc.read<Byte>(0)) % 4)) daysInMonth[1]++;
+
+  rtcTick(2);
+  if(rtc.read<Byte>(2) <= daysInMonth[BCD::decode(rtc.read<Byte>(1))-1]) return;
+  rtc.write<Byte>(2, 1);
+
+  //month
+  rtcTick(1);
+  if(rtc.read<Byte>(1) < 0x12) return;
+  rtc.write<Byte>(1, 1);
+
+  //year
+  rtcTick(0);
+}

mia/system/nintendo-64dd.cpp

@@ -14,7 +14,7 @@ auto Nintendo64DD::load(string location) -> bool {
   pak->append("pif.pal.rom",  Resource::Nintendo64::PIFPAL );
   pak->append("pif.sm5.rom",  Resource::Nintendo64::PIFSM5 );
   pak->append("64dd.ipl.rom", bios);
-  pak->append("time.rtc", 0x8);
+  pak->append("time.rtc", 0x10);
 
   if(auto fp = pak->write("time.rtc")) {
     for(auto address : range(fp->size())) fp->write(0xff);