scaffolding: build system, cartridge loader with MBC1/2/3/5, core types

1 files changed, 53 insertions, 0 deletions

diff --git a/src/cart.h b/src/cart.h
new file mode 100644
index 0000000..ec864bb
--- /dev/null
+++ b/src/cart.h
@@ -0,0 +1,53 @@
+#ifndef GBC_CART_H
+#define GBC_CART_H
+
+#include "types.h"
+
+typedef enum {
+    MBC_NONE,
+    MBC_1,
+    MBC_2,
+    MBC_3,
+    MBC_5,
+} MbcType;
+
+typedef struct {
+    u8  *rom;          // full ROM image
+    size_t rom_size;
+    int  rom_banks;    // number of 16KB banks
+
+    u8  *ram;          // external cartridge RAM
+    size_t ram_size;
+    int  ram_banks;    // number of 8KB banks
+
+    MbcType mbc;
+    bool has_ram;
+    bool has_battery;
+    bool has_rtc;
+    bool cgb;          // CGB flag set in header
+
+    char title[17];
+
+    // MBC state
+    bool ram_enabled;
+    u8   rom_bank;     // low bank register
+    u8   rom_bank_hi;  // high bits (mbc1 mode / mbc5)
+    u8   ram_bank;
+    u8   bank_mode;    // MBC1 banking mode select
+
+    // RTC (MBC3)
+    u8   rtc_reg[5];   // S, M, H, DL, DH
+    u8   rtc_latch;
+
+    char save_path[512];
+} Cart;
+
+// Load a ROM file into cart. Returns 0 on success.
+int cart_load(Cart *c, const char *path);
+void cart_free(Cart *c);
+void cart_save(Cart *c);
+
+u8   cart_read(Cart *c, u16 addr);
+void cart_write(Cart *c, u16 addr, u8 val);
+
+#endif