refactor: move emulation logic into sys

1 files changed, 78 insertions, 0 deletions

diff --git a/lib/nes/sys/cartridge.hh b/lib/nes/sys/cartridge.hh
new file mode 100644
index 0000000..a8b61a2
--- /dev/null
+++ b/lib/nes/sys/cartridge.hh
@@ -0,0 +1,78 @@
+#pragma once
+
+#include "nes/sys/types/status.hh"
+#include "nes/sys/mapper.hh"
+#include <cstddef>
+#include <vector>
+#include <string_view>
+
+namespace nes
+{
+	enum class name_table_arrangement
+	{
+		horizontal,
+		vertical,
+	};
+
+	class cartridge
+	{
+		static constexpr auto prg_rom_bank_size = std::size_t{ 16 * 1024 };
+		static constexpr auto chr_rom_bank_size = std::size_t{ 8 * 1024 };
+		static constexpr auto ram_bank_size = std::size_t{ 8 * 1024 };
+		static constexpr auto header_length = std::size_t{ 16 };
+
+		struct header
+		{
+			auto get_magic_0() const -> std::uint8_t { return value[0]; }
+			auto get_magic_1() const -> std::uint8_t { return value[1]; }
+			auto get_magic_2() const -> std::uint8_t { return value[2]; }
+			auto get_magic_3() const -> std::uint8_t { return value[3]; }
+			auto get_prg_rom_banks() const -> unsigned { return value[4]; }
+			auto get_chr_rom_banks() const -> unsigned { return value[5]; }
+			auto get_control_1() const -> std::uint8_t { return value[6]; }
+			auto get_control_2() const -> std::uint8_t { return value[7]; }
+			auto get_ram_banks() const -> unsigned { return value[8]; }
+			auto get_has_trainer() const -> bool { return get_control_1() & 0b00000100; }
+			auto get_mapper_low() const -> unsigned { return (get_control_1() & 0b11110000) >> 4; }
+			auto get_mapper_high() const -> unsigned { return (get_control_2() & 0b11110000) >> 0; }
+			auto get_name_table_arrangement() const -> name_table_arrangement { return static_cast<name_table_arrangement>((get_control_1() & 0b00000001) >> 0); }
+
+			std::uint8_t value[header_length]{};
+
+			explicit header(std::uint8_t const* v)
+			{
+				for (auto i = std::size_t{ 0 }; i < header_length; ++i)
+				{
+					value[i] = v[i];
+				}
+			}
+		};
+
+		status status_{ status::error_uninitialized };
+		std::vector<std::uint8_t> prg_rom_;
+		std::vector<std::uint8_t> chr_rom_;
+		std::vector<std::uint8_t> ram_;
+		name_table_arrangement name_table_arrangement_{};
+		mapper* mapper_{ &mapper::invalid() };
+
+	public:
+		explicit cartridge() = default;
+
+		static auto from_data(void const* data, std::size_t length) -> cartridge;
+		static auto from_file(std::string_view path) -> cartridge;
+
+		auto get_status() const -> status { return status_; }
+		auto get_prg_rom() const -> std::uint8_t const* { return prg_rom_.data(); }
+		auto get_prg_rom_length() const -> std::size_t { return prg_rom_.size(); }
+		auto get_chr_rom() const -> std::uint8_t const* { return chr_rom_.data(); }
+		auto get_chr_rom_length() const -> std::size_t { return chr_rom_.size(); }
+		auto get_ram() const -> std::uint8_t const* { return ram_.data(); }
+		auto get_ram_mut() -> std::uint8_t* { return ram_.data(); }
+		auto get_ram_length() const -> std::size_t { return ram_.size(); }
+		auto get_mapper() const -> mapper& { return *mapper_; }
+		auto get_name_table_arrangement() const -> name_table_arrangement { return name_table_arrangement_; }
+
+	private:
+		explicit cartridge(status);
+	};
+} // namespace nes
\ No newline at end of file