//---
// fxos.memory: Standard memory regions
//---

#ifndef LIBFXOS_MEMORY_H
#define LIBFXOS_MEMORY_H

#include <string>
#include <cstdint>

namespace FxOS {

/* Memory area enumeration with a few tools */
class MemoryArea
{
public:
	enum MemoryAreaName {
		/* Userspace seen from user and privileged mode */
		U0, P0,
		/* Second half of memory, only for privileged mode */
		P1, P2, P3, P4,
	};

	MemoryArea() = default;

	/* Construction from MemoryAreaName */
	constexpr MemoryArea(MemoryAreaName name): m_name(name) {}

	/* Start, end (last byte in area) and size of area */
	uint32_t start() const noexcept;
	uint32_t end()   const noexcept;
	uint32_t size()  const noexcept;

	/* Conversion to MemoryAreaName for switch */
	constexpr operator MemoryAreaName() noexcept { return m_name; }

	/* Comparison operators */
	constexpr bool operator==(MemoryArea a) const {
		return m_name == a.m_name;
	}
	constexpr bool operator!=(MemoryArea a) const {
		return m_name != a.m_name;
	}

private:
	MemoryAreaName m_name;
};

struct MemoryRegion
{
	/* Address space regions that correspond to standard (ie. contiguous
	   multi-addressable) memory */
	static MemoryRegion const &ROM;
	static MemoryRegion const &RAM;
	static MemoryRegion const &ROM_P2;
	static MemoryRegion const &RAM_P2;
	static MemoryRegion const &RS;
	static MemoryRegion const &ILRAM;
	static MemoryRegion const &XRAM;
	static MemoryRegion const &YRAM;

	/* Determine if an address falls into one of the standard regions.
	   Throws std::out_of_range if none. */
	static MemoryRegion const *region_for(uint32_t address);

	/* Short constructor which calls guess_flags() */
	MemoryRegion(std::string name, uint32_t start, uint32_t end,
		bool writable);

	/* Region name */
	std::string name {};

	/* Start address and end address. Generally the end address has one
	   additionnaly byte. This is okay since no region is supposed to
	   extend to the very end of the memory. */
	uint32_t start, end;

	/* The region is writable under normal conditions */
	bool writable;
	/* The cache is active in that region (if enabled) */
	bool cacheable;
	/* The MMU is active in that region (if enabled) */
	bool mappable;

	/* Returns the size of the region */
	uint32_t size() const noexcept;

	/* Returns the area associated to the region (assuming it is fully
	   contained in one, which should always be the case) */
	MemoryArea area() const noexcept;

	/* Automatically guess the cacheable and mappable flags */
	void guess_flags() noexcept;
};

} /* namespace FxOS */

#endif /* LIBFXOS_MEMORY_H */