- [CHG] Tot el codi mogut a la carpeta "source"

2026-06-03 18:07:16 +02:00
parent 88a02d49f7
commit 2fe0ce6152
32 changed files with 4 additions and 5 deletions
@@ -0,0 +1,82 @@
+#include "mbc1.h"
+#include "mem.h"
+#include "sm83.h"
+#include <stdlib.h>
+#include <SDL2/SDL.h>
+
+namespace mbc1
+{
+    #define ROM_BANK_SIZE 0x4000
+    #define RAM_BANK_SIZE 0x2000
+
+    uint8_t *rom;
+    uint8_t exram[4 * RAM_BANK_SIZE];
+
+    uint8_t current_rom_bank = 1;
+    uint8_t current_ram_bank = 0;
+    bool ram_enabled = false;
+    bool banking_mode = false; // false = ROM banking mode, true = RAM banking mode
+
+    void reset()
+    {
+        for (int i=0; i<4*RAM_BANK_SIZE; ++i) { exram[i] = 0; }
+    }
+
+    uint8_t readRom(uint16_t address)
+    {
+        if (address < 0x4000) {
+            // ROM Bank 0
+            return rom[address];
+        } else {
+            // Switchable ROM bank
+            uint32_t banked_address = (current_rom_bank * ROM_BANK_SIZE) + (address - 0x4000);
+            return rom[banked_address];
+        }
+    }
+
+    void writeRom(uint16_t address, uint8_t value)
+    {
+        if (address < 0x2000) {
+            // Enable/disable RAM
+            ram_enabled = (value & 0x0F) == 0x0A;
+        } else if (address < 0x4000) {
+            // Select ROM bank
+            value &= 0x1F; // Lower 5 bits are used
+            if (value == 0) value = 1; // Bank 0 is not allowed
+            current_rom_bank = (current_rom_bank & 0x60) | value;
+        } else if (address < 0x6000) {
+            // Select RAM bank or upper bits of ROM bank
+            if (banking_mode) {
+                current_ram_bank = value & 0x03; // 2 bits for RAM bank
+            } else {
+                current_rom_bank = (current_rom_bank & 0x1F) | ((value & 0x03) << 5);
+            }
+        } else {
+            // Select banking mode
+            banking_mode = value & 0x01;
+        }
+    }
+
+    uint8_t readRam(uint16_t address)
+    {
+        if (ram_enabled) {
+            uint32_t banked_address = (current_ram_bank * RAM_BANK_SIZE) + (address - 0xa000);
+            return exram[banked_address];
+        }
+        return 0xff; // Return open bus value when RAM is disabled
+    }
+
+    void writeRam(uint16_t address, uint8_t value)
+    {
+        if (ram_enabled) {
+            uint32_t banked_address = (current_ram_bank * RAM_BANK_SIZE) + (address - 0xa000);
+            exram[banked_address] = value;
+        }
+    }
+
+    void init(uint8_t *rom, uint32_t rom_size, uint32_t ram_size)
+    {
+        mbc1::rom = rom;
+        reset();
+    }
+}