Implement more parts of decoder

memory/mem_device.cpp

@@ -0,0 +1,14 @@
+#include "memory/mem_device.h"
+
+void Mem_device::write16(u16 addr, u16 data)
+{
+  write8(addr,   (u8)(data & 0xFF));
+  write8(addr+1, (u8)((data >> 8) & 0xFF));
+}
+
+u16 Mem_device::read16(u16 addr)
+{
+  u8 lsb = read8(addr);
+  u8 msb = read8(addr+1);
+  return ((u16)msb << 8) | (u16)lsb;
+}

memory/mem_device.h

@@ -7,6 +7,6 @@ public:
   virtual void write8(u16 addr, u8 data) = 0;
   virtual u8 read8(u16 addr) = 0;
 
-  virtual void write16(u16 addr, u16 data) = 0;
-  virtual u16 read16(u16 addr) = 0;
+  virtual void write16(u16 addr, u16 data);
+  virtual u16 read16(u16 addr);
 };

memory/ram.cpp

@@ -17,15 +17,3 @@ u8 RAM::read8(u16 addr) {
   if (addr >= size) return 0xFFu;
   return memory[addr];
 }
-
-void RAM::write16(u16 addr, u16 data) {
-  if(addr >= size - 1 || readonly) return;
-  u16 *ptr = (u16*)&memory[addr];
-  *ptr = data;
-}
-
-u16 RAM::read16(u16 addr) {
-  if(addr >= size - 1) return 0xFFFFu;
-  u16 *ptr = (u16*)&memory[addr];
-  return *ptr;
-}

memory/ram.h

@@ -14,7 +14,4 @@ public:
 
   virtual void write8(u16 addr, u8 data);
   virtual u8 read8(u16 addr);
-
-  virtual void write16(u16 addr, u16 data);
-  virtual u16 read16(u16 addr);
 };