vgbc/memory/bus.cpp

#include "bus.h"

Bus::Bus() : map() {}

std::optional<Bus::MapEntry> Bus::find_entry(u16 addr)
{
  for(auto it = map.begin(); it != map.end(); ++it)
    {
      if (it->range.contains(addr))
        return std::make_optional(*it);
    }

  return {};
}

void Bus::map_device(u16 start, u16 end, Mem_device* dev, u16 offset)
{
  map.push_back(Bus::MapEntry{ Range(start,end), offset, dev });
}

void Bus::write8(u16 addr, u8 data)
{
  auto mapentry = find_entry(addr);

  if(!mapentry) return;

  mapentry->dev->write8(addr - mapentry->range.start + mapentry->offset, data);
}

u8 Bus::read8(u16 addr)
{
  auto mapentry = find_entry(addr);

  if(!mapentry) return 0xFFu;

  return mapentry->dev->read8(addr - mapentry->range.start + mapentry->offset);
}

void Bus::write16(u16 addr, u16 data)
{
  auto mapentry = find_entry(addr);
  if(!mapentry) return;
  mapentry->dev->write16(addr - mapentry->range.start + mapentry->offset, data);
}

u16 Bus::read16(u16 addr)
{
  auto mapentry = find_entry(addr);
  if(!mapentry) return 0xFFFFu;
  return mapentry->dev->read16(addr - mapentry->range.start + mapentry->offset);
}