Basic memory implemented

drhelius · Jun 29, 2024 · 3f28cba · 3f28cba
1 parent 64ef65c
commit 3f28cba
Show file tree

Hide file tree

Showing 4 changed files with 176 additions and 24 deletions.
diff --git a/src/geargrafx_core.cpp b/src/geargrafx_core.cpp
@@ -17,6 +17,8 @@
  *
  */
 
+#include <stdlib.h>
+#include <time.h>
 #include "geargrafx_core.h"
 #include "common.h"
 #include "cartridge.h"
@@ -52,6 +54,8 @@ void GeargrafxCore::Init(GG_Pixel_Format pixel_format)
 {
     Debug("--== %s %s by Ignacio Sanchez ==--", GEARGRAFX_TITLE, GEARGRAFX_VERSION);
 
+    srand((unsigned int)time(NULL));
+
     m_pixel_format = pixel_format;
 
     m_cartridge = new Cartridge();

diff --git a/src/memory.cpp b/src/memory.cpp
@@ -17,22 +17,39 @@
  *
  */
 
+#include <stdlib.h>
 #include "memory.h"
 
 Memory::Memory(Cartridge* cartridge)
 {
     m_cartridge = cartridge;
+    InitPointer(m_wram);
 }
 
 Memory::~Memory()
 {
+    SafeDeleteArray(m_wram);
 }
 
 void Memory::Init()
 {
+    m_wram = new u8[0x2000];
     Reset();
 }
 
 void Memory::Reset()
 {
+    m_mpr[7] = 0x00;
+
+    for (int i = 0; i < 7; i++)
+    {
+        m_mpr[i] = rand() & 0xFF;
+    }
+
+    for (int i = 0; i < 0x2000; i++)
+    {
+        m_wram[i] = rand() & 0xFF;
+    }
 }
+
+
diff --git a/src/memory.h b/src/memory.h
@@ -33,9 +33,16 @@ class Memory
     void Reset();
     u8 Read(u16 address);
     void Write(u16 address, u8 value);
+    void SetMpr(u8 index, u8 value);
+    u8 GetMpr(u8 index);
 
 private:
     Cartridge* m_cartridge;
+    u8 m_mpr[8];
+    u8* m_wram;
+
+private:
+    u32 GetPhysicalAddress(u16 address);
 };
 
 #include "memory_inline.h"

diff --git a/src/memory_inline.h b/src/memory_inline.h
@@ -25,36 +25,160 @@
 
 inline u8 Memory::Read(u16 address)
 {
-    switch (address & 0xE000)
-    {
-        case 0x0000:
-        case 0x2000:
-        case 0x4000:
-        case 0x6000:
-        case 0x8000:
-        case 0xA000:
-        case 0xC000:
-        case 0xE000:
-        default:
-            return 0xFF;
+    u8 mpr_index = (address >> 13) & 0x07;
+    u8 mpr_value = m_mpr[mpr_index];
+    u32 physical_address = (mpr_value << 13) | (address & 0x1FFF);
+
+    if (mpr_value < 0x80)
+    {
+        // HuCard ROM
+        u8* rom = m_cartridge->GetROM();
+        return rom[physical_address];
+    }
+    else if (mpr_value < 0xF8)
+    {
+        // Unused
+        Debug("Unused read at %06X", physical_address);
+        return 0xFF;
+    }
+    else if (mpr_value < 0xFC)
+    {
+        // Work RAM
+        return m_wram[physical_address & 0x1FFF];
+    }
+    else if (mpr_value < 0xFF)
+    {
+        // Unused
+        Debug("Unused read at %06X", physical_address);
+        return 0xFF;
+    }
+    else
+    {
+        // Hardware Page
+        switch (physical_address & 0x001C00)
+        {
+            case 0x0000:
+                // HuC6270
+                Debug("HuC6270 read at %06X", physical_address);
+                return 0xFF;
+            case 0x0400:
+                // HuC6260
+                Debug("HuC6260 read at %06X", physical_address);
+                return 0xFF;
+            case 0x0800:
+                // PSG
+                Debug("PSG read at %06X", physical_address);
+                return 0xFF;
+            case 0x0C00:
+                // Timer
+                Debug("Timer read at %06X", physical_address);
+                return 0xFF;
+            case 0x1000:
+                // I/O
+                Debug("I/O read at %06X", physical_address);
+                return 0xFF;
+            case 0x1400:
+                // CD-ROM
+                Debug("CD-ROM read at %06X", physical_address);
+                return 0xFF;
+            case 0x1800:
+                // Unused
+                Debug("Unused read at %06X", physical_address);
+                return 0xFF;
+            case 0x1C00:
+                // Unused
+                Debug("Unused read at %06X", physical_address);
+                return 0xFF;
+            default:
+                return 0xFF;
+        }
     }
 }
 
 inline void Memory::Write(u16 address, u8 value)
 {
-    switch (address & 0xE000)
-    {
-        case 0x0000:
-        case 0x2000:
-        case 0x4000:
-        case 0x6000:
-        case 0x8000:
-        case 0xA000:
-        case 0xC000:
-        case 0xE000:
-        default:
-            break;
+    u8 mpr_index = (address >> 13) & 0x07;
+    u8 mpr_value = m_mpr[mpr_index];
+    u32 physical_address = (mpr_value << 13) | (address & 0x1FFF);
+
+    if (mpr_value < 0x80)
+    {
+        // HuCard ROM
+        Debug("Attempted write to HuCard ROM at %06X", physical_address);
     }
+    else if (mpr_value < 0xF8)
+    {
+        // Unused
+        Debug("Unused write at %06X", physical_address);
+    }
+    else if (mpr_value < 0xFC)
+    {
+        // Work RAM
+        m_wram[physical_address & 0x1FFF] = value;
+    }
+    else if (mpr_value < 0xFF)
+    {
+        // Unused
+        Debug("Unused write at %06X", physical_address);
+    }
+    else
+    {
+        // Hardware Page
+        switch (physical_address & 0x001C00)
+        {
+            case 0x0000:
+                // HuC6270
+                Debug("HuC6270 write at %06X", physical_address);
+                break;
+            case 0x0400:
+                // HuC6260
+                Debug("HuC6260 write at %06X", physical_address);
+                break;
+            case 0x0800:
+                // PSG
+                Debug("PSG write at %06X", physical_address);
+                break;
+            case 0x0C00:
+                // Timer
+                Debug("Timer write at %06X", physical_address);
+                break;
+            case 0x1000:
+                // I/O
+                Debug("I/O write at %06X", physical_address);
+                break;
+            case 0x1400:
+                // CD-ROM
+                Debug("CD-ROM write at %06X", physical_address);
+                break;
+            case 0x1800:
+                // Unused
+                Debug("Unused write at %06X", physical_address);
+                break;
+            case 0x1C00:
+                // Unused
+                Debug("Unused write at %06X", physical_address);
+                break;
+            default:
+                break;
+        }
+    }
+}
+
+inline void Memory::SetMpr(u8 index, u8 value)
+{
+    m_mpr[index] = value;
+}
+
+inline u8 Memory::GetMpr(u8 index)
+{
+    return m_mpr[index];
+}
+
+inline u32 Memory::GetPhysicalAddress(u16 address)
+{
+    u8 mpr_index = (address >> 13) & 0x07;
+    u8 mpr_value = m_mpr[mpr_index];
+    return (mpr_value << 13) | (address & 0x1FFF);
 }
 
 #endif /* MEMORY_INLINE_H */