fc: add prg ram to uxrom and cnrom mappers (ares-emulator#1557)

Some homebrew/aftermarket software calls for UXROM w/ PRG (NV)RAM. The licensed title Hayauchi Super Igo pairs CNROM with SRAM.
kannoneer · Jul 8, 2024 · 3de728f · 3de728f
1 parent 2b0738e
commit 3de728f
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Showing 3 changed files with 21 additions and 5 deletions.
diff --git a/ares/fc/cartridge/board/hvc-cnrom.cpp b/ares/fc/cartridge/board/hvc-cnrom.cpp
@@ -7,6 +7,7 @@ struct HVC_CNROM : Interface {
   }
 
   Memory::Readable<n8> programROM;
+  Memory::Writable<n8> programRAM;
   Memory::Readable<n8> characterROM;
   Memory::Writable<n8> characterRAM;
 
@@ -20,23 +21,29 @@ struct HVC_CNROM : Interface {
 
   auto load() -> void override {
     Interface::load(programROM, "program.rom");
+    Interface::load(programRAM, "save.ram");
     Interface::load(characterROM, "character.rom");
     Interface::load(characterRAM, "character.ram");
     mirror = pak->attribute("mirror") == "vertical";
     key = pak->attribute("chip/key").natural();
   }
 
   auto save() -> void override {
+    Interface::save(programRAM, "save.ram");
     Interface::save(characterRAM, "character.ram");
   }
 
   auto readPRG(n32 address, n8 data) -> n8 override {
-    if(address < 0x8000) return data;
+    if(address < 0x6000) return data;
+    if(address < 0x8000 && !programRAM) return data;
+    if(address < 0x8000) return programRAM.read(address);
     return programROM.read((n15)address);
   }
 
   auto writePRG(n32 address, n8 data) -> void override {
-    if(address < 0x8000) return;
+    if(address < 0x6000) return;
+    if(address < 0x8000 && !programRAM) return;
+    if(address < 0x8000) return programRAM.write(address, data);
     characterBank = data & programROM.read((n15)address);
     characterEnable = (data == key);
   }
@@ -70,6 +77,7 @@ struct HVC_CNROM : Interface {
   }
 
   auto serialize(serializer& s) -> void override {
+    s(programRAM);
     s(characterRAM);
     s(mirror);
     s(key);

diff --git a/ares/fc/cartridge/board/hvc-uxrom.cpp b/ares/fc/cartridge/board/hvc-uxrom.cpp
@@ -8,6 +8,7 @@ struct HVC_UxROM : Interface {
   }
 
   Memory::Readable<n8> programROM;
+  Memory::Writable<n8> programRAM;
   Memory::Readable<n8> characterROM;
   Memory::Writable<n8> characterRAM;
 
@@ -22,17 +23,21 @@ struct HVC_UxROM : Interface {
 
   auto load() -> void override {
     Interface::load(programROM, "program.rom");
+    Interface::load(programRAM, "save.ram");
     Interface::load(characterROM, "character.rom");
     Interface::load(characterRAM, "character.ram");
     mirror = pak->attribute("mirror") == "vertical";
   }
 
   auto save() -> void override {
+    Interface::save(programRAM, "save.ram");
     Interface::save(characterRAM, "character.ram");
   }
 
   auto readPRG(n32 address, n8 data) -> n8 override {
-    if(address < 0x8000) return data;
+    if(address < 0x6000) return data;
+    if(address < 0x8000 && !programRAM) return data;
+    if(address < 0x8000) return programRAM.read(address);
     n8 bank;
     switch(address >> 14 & 1) {
     case 0: bank = (revision == Revision::UNROMA ? (n8)0x00 : programBank); break;
@@ -42,7 +47,9 @@ struct HVC_UxROM : Interface {
   }
 
   auto writePRG(n32 address, n8 data) -> void override {
-    if(address < 0x8000) return;
+    if(address < 0x6000) return;
+    if(address < 0x8000 && !programRAM) return;
+    if(address < 0x8000) return programRAM.write(address, data);
     programBank = data;
     if(revision == Revision::UN1ROM) programBank >>= 2;
   }
@@ -69,6 +76,7 @@ struct HVC_UxROM : Interface {
   }
 
   auto serialize(serializer& s) -> void override {
+    s(programRAM);
     s(characterRAM);
     s(mirror);
     s(programBank);

diff --git a/ares/fc/system/serialization.cpp b/ares/fc/system/serialization.cpp
@@ -1,4 +1,4 @@
-static const string SerializerVersion = "v147";
+static const string SerializerVersion = "v148";
 
 auto System::serialize(bool synchronize) -> serializer {
   if(synchronize) scheduler.enter(Scheduler::Mode::Synchronize);