#include <fxos/memory.h>
#include <stdexcept>
#include <array>

namespace FxOS {

//---
//  Overview of the memory areas
//---

uint32_t MemoryArea::start() const noexcept
{
	switch(m_name)
	{
	case U0: return 0x00000000;
	case P0: return 0x00000000;
	case P1: return 0x80000000;
	case P2: return 0xa0000000;
	case P3: return 0xc0000000;
	case P4: return 0xe0000000;
	}

	return 0;
}

uint32_t MemoryArea::end() const noexcept
{
	switch(m_name)
	{
	case U0: return 0x7fffffff;
	case P0: return 0x7fffffff;
	case P1: return 0x9fffffff;
	case P2: return 0xbfffffff;
	case P3: return 0xdfffffff;
	case P4: return 0xffffffff;
	}

	return -1;
}

uint32_t MemoryArea::size() const noexcept
{
	return this->end() - this->start() + 1;
}

//---
//  Fine memory region management
//---

MemoryRegion::MemoryRegion():
	name {"null"}, start {0x00000000}, end {0x00000000}, writable {false}
{
}

MemoryRegion::MemoryRegion(std::string name, uint32_t start, uint32_t end,
	bool writable):
	name {name}, start {start}, end {end}, writable {writable}
{
	this->guess_flags();
}

uint32_t MemoryRegion::size() const noexcept
{
	return end - start;
}

MemoryArea MemoryRegion::area() const noexcept
{
	using Area = MemoryArea;
	Area areas[5] = { Area::P4, Area::P3, Area::P2, Area::P1, Area::P0 };

	for(int i = 0; i < 5; i++)
	{
		if(start >= areas[i].start()) return areas[i];
	}

	return Area::P0;
}

void MemoryRegion::guess_flags() noexcept
{
	switch(this->area())
	{
	case MemoryArea::U0:
	case MemoryArea::P0:
	case MemoryArea::P3:
		cacheable = true;
		mappable = true;
		break;

	case MemoryArea::P1:
		cacheable = true;
		mappable = false;
		break;

	case MemoryArea::P2:
	case MemoryArea::P4:
		cacheable = false;
		mappable = false;
		break;
	}
}

using R  = MemoryRegion;

/* Basic memory regions */
R const &R::ROM    = MemoryRegion("ROM",    0x80000000, 0x81ffffff, false);
R const &R::RAM    = MemoryRegion("RAM",    0x88000000, 0x88040000, true);
R const &R::ROM_P2 = MemoryRegion("ROM_P2", 0xa0000000, 0xa07fffff, false);
R const &R::RAM_P2 = MemoryRegion("RAM_P2", 0xa8000000, 0xa8040000, true);
R const &R::RS     = MemoryRegion("RS",     0xfd800000, 0xfd8007ff, true);
R const &R::ILRAM  = MemoryRegion("ILRAM",  0xe5200000, 0xe5203fff, true);
R const &R::XRAM   = MemoryRegion("XRAM",   0xe5007000, 0xe5008fff, true);
R const &R::YRAM   = MemoryRegion("YRAM",   0xe5017000, 0xe5018fff, true);

MemoryRegion const *MemoryRegion::region_for(uint32_t address)
{
	MemoryRegion const *regs[8] = {
		&R::ROM, &R::RAM, &R::ROM_P2, &R::RAM_P2,
		&R::RS, &R::ILRAM, &R::XRAM, &R::YRAM
	};

	for(int i = 0; i < 8; i++)
	{
		if(regs[i]->start <= address && address < regs[i]->end)
			return regs[i];
	}

	return nullptr;
}

MemoryRegion::MemoryRegion(std::string name)
{
	MemoryRegion const *regs[8] = {
		&R::ROM, &R::RAM, &R::ROM_P2, &R::RAM_P2,
		&R::RS, &R::ILRAM, &R::XRAM, &R::YRAM
	};

	for(int i = 0; i < 8; i++)
	{
		if(regs[i]->name == name)
		{
			*this = *regs[i];
			return;
		}
	}

	throw std::runtime_error("No standard region named '" + name + "'");
}

} /* namespace FxOS */