Merge pull request #219

Ross

Author: KimJorgensen

README.md

@@ -42,6 +42,7 @@ The following cartridge types are currently supported:
 * Magic Desk, Domark, HES Australia
 * Super Snapshot v5
 * Comal-80
+* Ross
 * EasyFlash
 * Prophet64
 * Freeze Frame

firmware/cartridges/cartridge.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2023 Kim Jørgensen
+ * Copyright (c) 2019-2025 Kim Jørgensen
  *
  * This software is provided 'as-is', without any express or implied
  * warranty.  In no event will the authors be held liable for any damages
@@ -44,6 +44,7 @@ static u32 freezer_state;
 #include "magic_desk.c"
 #include "super_snapshot_5.c"
 #include "comal80.c"
+#include "ross.c"
 #include "easyflash.c"
 #include "easyflash_3.c"
 #include "prophet64.c"
@@ -107,8 +108,10 @@ static void (*crt_get_handler(u32 cartridge_type, bool vic_support)) (void)
 
         case CRT_COMAL_80:
             return comal80_handler;
-#endif
 
+        case CRT_ROSS:
+            return ross_handler;
+#endif
         case CRT_OCEAN_TYPE_1:
         case CRT_EASYFLASH:
             if (cartridge_type != CRT_EASYFLASH || vic_support)
@@ -181,6 +184,10 @@ static void crt_init(DAT_CRT_HEADER *crt_header)
             comal80_init();
             break;
 
+        case CRT_ROSS:
+            ross_init(crt_header);
+            break;
+
         case CRT_EASYFLASH:
             ef_init();
             break;

firmware/cartridges/ross.c

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2019-2025 Kim Jørgensen and Sven Oliver (SvOlli) Moll
+ * Copyright (c) 2024 Vladan Nikolic
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+/*
+ * The Ross cartridge supports 16 kb, 32 kb, and 64 kb ROM
+ *
+ * Any read or write to $DE00-$DEFF will switch banks
+ * Any read or write to $DF00-$DFFF turns ROM off
+ *
+ * See https://github.com/msolajic/EX-YU_64K_C64_CART for more details
+ */
+
+static u32 ross_bank;
+
+/*************************************************
+* C64 bus read callback
+*************************************************/
+FORCE_INLINE bool ross_read_handler(u32 control, u32 addr)
+{
+    if ((control & (C64_ROML|C64_ROMH)) != (C64_ROML|C64_ROMH))
+    {
+        C64_DATA_WRITE(crt_ptr[addr & 0x3fff]);
+        return true;
+    }
+
+    if (!(control & C64_IO1))
+    {
+        // Any read to IO1: Switch bank
+        crt_ptr = crt_banks[ross_bank & 0x03];
+        ross_bank >>= 2;
+        return false;
+    }
+
+    if (!(control & C64_IO2))
+    {
+        // Any read to IO2: Disable ROM
+        C64_CRT_CONTROL(STATUS_LED_OFF|CRT_PORT_NONE);
+        return false;
+    }
+
+    return false;
+}
+
+/*************************************************
+* C64 bus write callback
+*************************************************/
+FORCE_INLINE void ross_write_handler(u32 control, u32 addr, u32 data)
+{
+    if (!(control & C64_IO1))
+    {
+        // Any write to IO1: Switch bank
+        crt_ptr = crt_banks[ross_bank & 0x03];
+        ross_bank >>= 2;
+        return;
+    }
+
+    if (!(control & C64_IO2))
+    {
+        // Any write to IO2: Disable ROM
+        C64_CRT_CONTROL(STATUS_LED_OFF|CRT_PORT_NONE);
+        return;
+    }
+}
+
+static void ross_init(DAT_CRT_HEADER *crt_header)
+{
+    if (crt_header->banks <= 1)
+    {
+        // 16 kb cartridge - no bank switching
+        ross_bank = 0;
+    }
+    else if (crt_header->banks == 2)
+    {
+        // 32 kb cartridge - 2 banks
+        ross_bank = (1 << 4) | (0 << 2) | (1 << 0);
+    }
+    else
+    {
+        // 64 kb cartridge - 4 banks
+        ross_bank = (3 << 4) | (2 << 2) | (1 << 0);
+    }
+}
+
+C64_BUS_HANDLER(ross)