From a2edbedb520f2ada936c00308cc6dfd75717b0d8 Mon Sep 17 00:00:00 2001 From: Hannes Schulze Date: Mon, 13 Jan 2025 23:04:30 +0100 Subject: read cartridges --- src/nes/CMakeLists.txt | 2 ++ src/nes/cartridge.cc | 65 +++++++++++++++++++++++++++++++++++++++++++++ src/nes/cartridge.hh | 33 +++++++++++++++++++++++ src/nes/nes.cc | 12 +++++++-- src/nes/nes.hh | 6 ++++- src/nes/util/CMakeLists.txt | 1 + src/nes/util/address.hh | 40 ++++++++++++++++++++++++++++ 7 files changed, 156 insertions(+), 3 deletions(-) create mode 100644 src/nes/cartridge.cc create mode 100644 src/nes/cartridge.hh create mode 100644 src/nes/util/address.hh (limited to 'src/nes') diff --git a/src/nes/CMakeLists.txt b/src/nes/CMakeLists.txt index 560dcdd..c217219 100644 --- a/src/nes/CMakeLists.txt +++ b/src/nes/CMakeLists.txt @@ -5,5 +5,7 @@ target_sources( PRIVATE nes.hh nes.cc + cartridge.hh + cartridge.cc display.hh display.cc) \ No newline at end of file diff --git a/src/nes/cartridge.cc b/src/nes/cartridge.cc new file mode 100644 index 0000000..5970d2a --- /dev/null +++ b/src/nes/cartridge.cc @@ -0,0 +1,65 @@ +#include "nes/cartridge.hh" +#include + +namespace +{ + constexpr auto prg_rom_bank_size = std::size_t{ 16 * 1024 }; + constexpr auto chr_rom_bank_size = std::size_t{ 8 * 1024 }; + constexpr auto ram_bank_size = std::size_t{ 8 * 1024 }; +} // namespace + +namespace nes +{ + auto cartridge::from_data(void const* data, std::size_t const length) -> cartridge + { + auto const bytes = static_cast(data); + auto res = cartridge{}; + res.is_valid_ = true; + + // Parse header. + if (length < 16) { return cartridge{}; } + if (bytes[0] != 'N' || bytes[1] != 'E' || bytes[2] != 'S' || bytes[3] != 0x1A) { return cartridge{}; } + auto const prg_rom_banks = bytes[4]; + auto const chr_rom_banks = bytes[5]; + auto const control_1 = bytes[6]; + auto const control_2 = bytes[7]; + auto const ram_banks = (bytes[8] != 0) ? bytes[8] : 1; + auto const has_trainer = (control_1 & 0b00000100) != 0; + + res.mapper_number_ = + (control_1 & 0b11110000) >> 4 | + (control_2 & 0b11110000) >> 0; + + // Load program data. + auto offset = 16; + if (has_trainer) { offset += 512; } + + auto const prg_rom_size = prg_rom_banks * prg_rom_bank_size; + if (length < offset + prg_rom_size) { return cartridge{}; } + res.prg_rom_ = std::vector(&bytes[offset], &bytes[offset + prg_rom_size]); + + offset += prg_rom_size; + + auto const chr_rom_size = chr_rom_banks * chr_rom_bank_size; + if (length < offset + chr_rom_size) { return cartridge{}; } + res.chr_rom_ = std::vector(&bytes[offset], &bytes[offset + chr_rom_size]); + + res.ram_ = std::vector(ram_banks * ram_bank_size, std::uint8_t{ 0 }); + + return res; + } + + auto cartridge::from_file(std::string_view const path) -> cartridge + { + auto stream = std::ifstream{ path, std::ios::binary }; + if (!stream.good()) { return cartridge{}; } + + stream.seekg(0, std::ios::end); + auto const length = stream.tellg(); + stream.seekg(0, std::ios::beg); + auto data = std::vector(length); + stream.read(reinterpret_cast(data.data()), data.size()); + + return from_data(data.data(), data.size()); + } +} // namespace nes \ No newline at end of file diff --git a/src/nes/cartridge.hh b/src/nes/cartridge.hh new file mode 100644 index 0000000..a334125 --- /dev/null +++ b/src/nes/cartridge.hh @@ -0,0 +1,33 @@ +#pragma once + +#include +#include +#include + +namespace nes +{ + class cartridge + { + bool is_valid_{ false }; + std::vector prg_rom_; + std::vector chr_rom_; + std::vector ram_; + std::uint8_t mapper_number_{ 0 }; + + 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 is_valid() const -> bool { return is_valid_; } + 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_number() const -> std::uint8_t { return mapper_number_; } + }; +} // namespace nes \ No newline at end of file diff --git a/src/nes/nes.cc b/src/nes/nes.cc index c503d65..63175aa 100644 --- a/src/nes/nes.cc +++ b/src/nes/nes.cc @@ -1,12 +1,20 @@ #include "nes/nes.hh" #include "nes/display.hh" #include "nes/util/rgb.hh" +#include namespace nes { - nes::nes(display& display) - : display_{ display } + nes::nes(cartridge cartridge, display& display) + : cartridge_{ std::move(cartridge) } + , display_{ display } { + if (!cartridge_.is_valid()) + { + std::cerr << "Cartridge not valid!" << std::endl; + std::abort(); + } + display.clear(rgb::from_hex(0xFF0000)); display.switch_buffers(); } diff --git a/src/nes/nes.hh b/src/nes/nes.hh index ab975f0..924ddd4 100644 --- a/src/nes/nes.hh +++ b/src/nes/nes.hh @@ -1,15 +1,19 @@ #pragma once +#include "nes/cartridge.hh" + namespace nes { class display; + /// The main console abstraction. class nes { + cartridge cartridge_; display& display_; public: - explicit nes(display&); + explicit nes(cartridge, display&); nes(nes const&) = delete; nes(nes&&) = delete; diff --git a/src/nes/util/CMakeLists.txt b/src/nes/util/CMakeLists.txt index c2255dd..1d30125 100644 --- a/src/nes/util/CMakeLists.txt +++ b/src/nes/util/CMakeLists.txt @@ -1,4 +1,5 @@ target_sources( nes PRIVATE + address.hh rgb.hh) \ No newline at end of file diff --git a/src/nes/util/address.hh b/src/nes/util/address.hh new file mode 100644 index 0000000..f02b66b --- /dev/null +++ b/src/nes/util/address.hh @@ -0,0 +1,40 @@ +#pragma once + +#include + +namespace nes +{ + /// An address on the NES. + class address + { + std::uint16_t absolute_{ 0 }; + + public: + /// Create a zero address. + explicit address() = default; + + /// Create an address from its absolute value. + explicit address(std::uint16_t const absolute) + : absolute_{ absolute } + { + } + + /// Get the absolute address value. + auto get_absolute() const -> std::uint16_t + { + return absolute_; + } + + /// Get the address page (the first 8 bits). + auto get_page() const -> std::uint8_t + { + return static_cast((get_absolute() & 0xFF00) >> 8); + } + + /// Get the offset within the page (the last 8 bits). + auto get_offset() const -> std::uint8_t + { + return static_cast((get_absolute() & 0x00FF) >> 0); + } + }; +} // namespace nes \ No newline at end of file -- cgit v1.3.1