restructure project

1 files changed, 73 insertions, 0 deletions

diff --git a/lib/nes/util/address.hh b/lib/nes/util/address.hh
new file mode 100644
index 0000000..7987d07
--- /dev/null
+++ b/lib/nes/util/address.hh
@@ -0,0 +1,73 @@
+#pragma once
+
+#include <cstdint>
+
+namespace nes
+{
+	/// An address on the NES.
+	class address
+	{
+		std::uint16_t absolute_{ 0 };
+
+	public:
+		/// Create a zero address.
+		constexpr explicit address() = default;
+
+		/// Create an address from its absolute value.
+		constexpr explicit address(std::uint16_t const absolute)
+			: absolute_{ absolute }
+		{
+		}
+
+		/// Create an address from its page and offset combination.
+		constexpr explicit address(std::uint8_t const page, std::uint8_t const offset)
+			: address{ static_cast<std::uint16_t>((page << 8) | (offset << 0)) }
+		{
+		}
+
+		/// Get the absolute address value.
+		constexpr auto get_absolute() const -> std::uint16_t
+		{
+			return absolute_;
+		}
+
+		/// Get the address page (the first 8 bits).
+		constexpr auto get_page() const -> std::uint8_t
+		{
+			return static_cast<std::uint8_t>((get_absolute() & 0xFF00) >> 8);
+		}
+
+		/// Get the offset within the page (the last 8 bits).
+		constexpr auto get_offset() const -> std::uint8_t
+		{
+			return static_cast<std::uint8_t>((get_absolute() & 0x00FF) >> 0);
+		}
+	};
+
+	constexpr auto operator==(address const a, address const b) -> bool { return a.get_absolute() == b.get_absolute(); }
+	constexpr auto operator!=(address const a, address const b) -> bool { return a.get_absolute() != b.get_absolute(); }
+	constexpr auto operator<(address const a, address const b) -> bool { return a.get_absolute() < b.get_absolute(); }
+	constexpr auto operator>(address const a, address const b) -> bool { return a.get_absolute() > b.get_absolute(); }
+	constexpr auto operator<=(address const a, address const b) -> bool { return a.get_absolute() <= b.get_absolute(); }
+	constexpr auto operator>=(address const a, address const b) -> bool { return a.get_absolute() >= b.get_absolute(); }
+
+	constexpr auto operator+(address const a, std::uint16_t const b) -> address
+	{
+		return address{ static_cast<std::uint16_t>(a.get_absolute() + b) };
+	}
+
+	constexpr auto operator+(std::uint16_t const a, address const b) -> address
+	{
+		return address{ static_cast<std::uint16_t>(a + b.get_absolute()) };
+	}
+
+	constexpr auto operator-(address const a, std::uint16_t const b) -> address
+	{
+		return address{ static_cast<std::uint16_t>(a.get_absolute() - b) };
+	}
+
+	constexpr auto operator%(address const a, std::uint16_t const b) -> address
+	{
+		return address{ static_cast<std::uint16_t>(a.get_absolute() % b) };
+	}
+} // namespace nes
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