copy reference implementation

1 files changed, 64 insertions, 0 deletions

diff --git a/lib/nes/ref/mapper.hh b/lib/nes/ref/mapper.hh
new file mode 100644
index 0000000..671e1d4
--- /dev/null
+++ b/lib/nes/ref/mapper.hh
@@ -0,0 +1,64 @@
+#pragma once
+
+#include "nes/util/address.hh"
+
+namespace nes::ref
+{
+	class cartridge;
+
+	class mapper
+	{
+		using read_cpu_func = std::uint8_t(mapper::*)(address);
+		using write_cpu_func = void(mapper::*)(address, std::uint8_t);
+		using read_ppu_func = std::uint8_t(mapper::*)(address, std::uint8_t const* vram);
+		using write_ppu_func = void(mapper::*)(address, std::uint8_t* vram, std::uint8_t);
+
+		cartridge& cartridge_;
+		read_cpu_func read_cpu_;
+		write_cpu_func write_cpu_;
+		read_ppu_func read_ppu_;
+		write_ppu_func write_ppu_;
+
+	public:
+		static auto select(cartridge&) -> mapper;
+
+		mapper(mapper const&) = delete;
+		mapper(mapper&&) = delete;
+		auto operator=(mapper const&) -> mapper& = delete;
+		auto operator=(mapper&&) -> mapper& = delete;
+
+		auto read_cpu(address const addr) -> std::uint8_t
+		{
+			return (this->*read_cpu_)(addr);
+		}
+
+		auto write_cpu(address const addr, std::uint8_t const value) -> void
+		{
+			(this->*write_cpu_)(addr, value);
+		}
+
+		auto read_ppu(address const addr, std::uint8_t const* vram) -> std::uint8_t
+		{
+			return (this->*read_ppu_)(addr, vram);
+		}
+
+		auto write_ppu(address const addr, std::uint8_t* vram, std::uint8_t const value) -> void
+		{
+			(this->*write_ppu_)(addr, vram, value);
+		}
+
+	private:
+		explicit mapper(
+			cartridge& cartridge,
+			read_cpu_func read_cpu, write_cpu_func write_cpu,
+			read_ppu_func read_ppu, write_ppu_func write_ppu);
+
+		// Implementations
+
+		auto nrom_read_cpu(address) -> std::uint8_t;
+		auto nrom_write_cpu(address, std::uint8_t) -> void;
+		auto nrom_read_ppu(address, std::uint8_t const* vram) -> std::uint8_t;
+		auto nrom_write_ppu(address, std::uint8_t* vram, std::uint8_t) -> void;
+		auto nrom_mirrored_vram_address(address) const -> unsigned;
+	};
+} // namespace nes::ref
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