vgbc/memory/bootrom_overlay.cpp

#include "memory/bootrom_overlay.h"

BootRom::BootRom(Mem_device* lowmem, Mem_device* highmem, Mem_device* backend)
  : lowmem(lowmem), highmem(highmem), backend(backend), enabled(true),
    lowrange(0x0000, 0x00FF), highrange(0x0200, 0x08FF)
{}

void BootRom::enable()
{
  enabled = true;
}
void BootRom::disable()
{
  enabled = false;
}

void BootRom::write8(u16 addr, u8 data)
{
  if(enabled && (lowrange.contains(addr) || highrange.contains(addr)))
    return;

  backend->write8(addr, data);
}

u8 BootRom::read8(u16 addr)
{
  if(enabled && lowrange.contains(addr))
    return lowmem->read8(addr);
  else if(enabled && highrange.contains(addr))
    return highmem->read8(addr);
  else
    return backend->read8(addr);
}

void BootRom::write16(u16 addr, u16 data)
{
  if(enabled && (lowrange.contains(addr) || highrange.contains(addr)))
    return;

  backend->write16(addr, data);
}

u16 BootRom::read16(u16 addr)
{
  if(enabled && lowrange.contains(addr))
    return lowmem->read16(addr);
  else if(enabled && highrange.contains(addr))
    return highmem->read16(addr);
  else
    return backend->read16(addr);
}