msx: fix conflicts between rom and scc with KonamiSCC mapper

ares-emulator · Oct 18, 2023 · 88a14fb · 88a14fb
1 parent 5f55b6c
commit 88a14fb
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/ares/msx/cartridge/board/konami-scc.cpp b/ares/msx/cartridge/board/konami-scc.cpp
@@ -48,6 +48,9 @@ struct KonamiSCC : Interface {
     if(address >= 0x0000 && address <= 0x1fff) data = rom.read(bank[2] << 13 | (n13)address);
     if(address >= 0x2000 && address <= 0x3fff) data = rom.read(bank[3] << 13 | (n13)address);
 
+    //scc is mapped in bank 0x3f for 98xx-98ff
+    if(bank[2].bit(0, 5) != 0x3f) return data;
+
     address.bit(8) = 0;  //SCC ignores A8
 
     if(address >= 0x9800 && address <= 0x981f) {
@@ -88,6 +91,9 @@ struct KonamiSCC : Interface {
     if(address >= 0x9000 && address <= 0x97ff) bank[2] = data;
     if(address >= 0xb000 && address <= 0xb7ff) bank[3] = data;
 
+    //scc is mapped in bank 0x3f for 98xx-98ff
+    if(bank[2].bit(0, 5) != 0x3f) return;
+
     address.bit(8) = 0;  //SCC ignores A8
 
     if(address >= 0x9800 && address <= 0x981f && !test.bit(6)) {