genesis-plus-gx.patch

commit bc4f11c187d3281c19310034b9ddc7578740f3d9
Author: Joey Parrish <joeyparrish@google.com>
Date:   Sun Oct 13 19:42:58 2024 -0700

    Emulate Kinetoscope hardware in Genesis-Plus-GX
    
    Patch based on https://github.com/libretro/Genesis-Plus-GX revision 7de0f0b6

diff --git a/LICENSE.txt b/LICENSE.txt
index eba63d1..3d1fd37 100644
--- a/LICENSE.txt
+++ b/LICENSE.txt
@@ -879,3 +879,30 @@ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
+
+
+----------------------------------------------------------------------------------------
+
+Kinetoscope emulation adapter is distributed under the following license:
+
+MIT License
+
+Copyright (c) 2024 Joey Parrish
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/Makefile.libretro b/Makefile.libretro
index 0d870ef..d6bd5a0 100644
--- a/Makefile.libretro
+++ b/Makefile.libretro
@@ -425,6 +425,7 @@ else ifeq ($(platform), libnx)
 else ifeq ($(platform), emscripten)
    TARGET := $(TARGET_NAME)_libretro_$(platform).bc
    ENDIANNESS_DEFINES := -DLSB_FIRST -DALIGN_LONG -DBYTE_ORDER=LITTLE_ENDIAN -DHAVE_ZLIB
+   LDFLAGS += -s FETCH=1
    STATIC_LINKING = 1
 
 # RS90
@@ -881,6 +882,9 @@ all: $(TARGET)
 %.o: %.c
 	$(CC) $(OBJOUT)$@ -c $< $(CFLAGS) $(LIBRETRO_CFLAGS)
 
+core/cart_hw/kinetoscope_adapter.o: core/cart_hw/kinetoscope_adapter.c core/kinetoscope/emulator-patches/kinetoscope.c core/kinetoscope/emulator-patches/fetch.c
+	$(CC) $(OBJOUT)$@ -c $< $(CFLAGS) $(LIBRETRO_CFLAGS)
+
 $(TARGET): $(OBJECTS)
 ifeq ($(STATIC_LINKING), 1)
 	$(AR) rcs $@ $(OBJECTS)
diff --git a/core/cart_hw/kinetoscope_adapter.c b/core/cart_hw/kinetoscope_adapter.c
new file mode 100644
index 0000000..e94a1b4
--- /dev/null
+++ b/core/cart_hw/kinetoscope_adapter.c
@@ -0,0 +1,45 @@
+// Kinetoscope: A Sega Genesis Video Player
+//
+// Copyright (c) 2024 Joey Parrish
+//
+// See MIT License in LICENSE.txt
+
+// Adapter between Kinetoscope emulation and Genesis Plus GX.
+
+#include "kinetoscope/emulator-patches/kinetoscope.c"
+
+#include "kinetoscope_adapter.h"
+#include "shared.h"
+
+void kinetoscope_adapter_reset() {
+  uint8_t* sram_buffer = (uint8_t*)kinetoscope_init();
+
+  // 0x20 here represents 2MB in the map.  Each "unit" of the memory map is
+  // 64kB.  We map each of these units to the corresponding offset in
+  // sram_buffer.
+  for (int i = 0x20; i < 0x40; ++i) {
+    m68k.memory_map[i].base = sram_buffer;
+
+    m68k.memory_map[i].read8 = NULL;
+    m68k.memory_map[i].read16 = NULL;
+    m68k.memory_map[i].write8 = m68k_unused_8_w;
+    m68k.memory_map[i].write16 = m68k_unused_16_w;
+
+    zbank_memory_map[i].read = NULL;
+    zbank_memory_map[i].write = zbank_unused_w;
+
+    sram_buffer += (64 << 10);  // 64kB
+  }
+}
+
+void kinetoscope_adapter_write(unsigned int address, unsigned int data) {
+  // The Kinetoscope emulator expects only the low 8 bits of this address.
+  address &= 0xff;
+  kinetoscope_write_16((uint32_t)address, NULL, (uint16_t)data);
+}
+
+unsigned int kinetoscope_adapter_read(unsigned int address) {
+  // The Kinetoscope emulator expects only the low 8 bits of this address.
+  address &= 0xff;
+  return (unsigned int)kinetoscope_read_16((uint32_t)address, NULL);
+}
diff --git a/core/cart_hw/kinetoscope_adapter.h b/core/cart_hw/kinetoscope_adapter.h
new file mode 100644
index 0000000..654f816
--- /dev/null
+++ b/core/cart_hw/kinetoscope_adapter.h
@@ -0,0 +1,16 @@
+// Kinetoscope: A Sega Genesis Video Player
+//
+// Copyright (c) 2024 Joey Parrish
+//
+// See MIT License in LICENSE.txt
+
+// Adapter between Kinetoscope emulation and Genesis Plus GX.
+
+#ifndef _KINETOSCOPE_ADAPTER_H_
+#define _KINETOSCOPE_ADAPTER_H_
+
+extern void kinetoscope_adapter_reset(void);
+extern void kinetoscope_adapter_write(unsigned int address, unsigned int data);
+extern unsigned int kinetoscope_adapter_read(unsigned int address);
+
+#endif
diff --git a/core/cart_hw/md_cart.c b/core/cart_hw/md_cart.c
index 766289d..07d75e1 100644
--- a/core/cart_hw/md_cart.c
+++ b/core/cart_hw/md_cart.c
@@ -45,6 +45,7 @@
 #include "eeprom_i2c.h"
 #include "eeprom_spi.h"
 #include "megasd.h"
+#include "kinetoscope_adapter.h"
 
 /* Cart database entry */
 typedef struct
@@ -549,6 +550,13 @@ void md_cart_init(void)
     cart.special |= HW_MEGASD;
     cart.hw.time_w = megasd_rom_mapper_w;
   }
+  else if (strstr(rominfo.consoletype,"SEGA KINETOSCOPE"))
+  {
+    /* Kinetoscope cartridge hardware */
+    cart.special |= HW_KINETOSCOPE;
+    cart.hw.time_w = kinetoscope_adapter_write;
+    cart.hw.time_r = kinetoscope_adapter_read;
+  }
   else if (strstr(rominfo.domestic,"SUPER STREET FIGHTER2"))
   {
     /* SSF2 mapper */
@@ -848,6 +856,12 @@ void md_cart_reset(int hard_reset)
     megasd_reset();
   }
 
+  /* MegaSD hardware */
+  if (cart.special & HW_KINETOSCOPE)
+  {
+    kinetoscope_adapter_reset();
+  }
+
   /* SVP chip */
   if (svp)
   {
diff --git a/core/cart_hw/md_cart.h b/core/cart_hw/md_cart.h
index 58687b9..f142356 100644
--- a/core/cart_hw/md_cart.h
+++ b/core/cart_hw/md_cart.h
@@ -62,9 +62,10 @@
 #define HW_ADDON_NONE    0x03
 
 /* Special hardware (0x01 & 0x02 reserved for Master System 3-D glasses & Terebi Oekaki) */
-#define HW_J_CART   0x04
-#define HW_LOCK_ON  0x08
-#define HW_MEGASD   0x10
+#define HW_J_CART       0x04
+#define HW_LOCK_ON      0x08
+#define HW_MEGASD       0x10
+#define HW_KINETOSCOPE  0x20
 
 /* Cartridge extra hardware */
 typedef struct