cheat_engine: Add parser and interpreter for game cheats

src/core/file_sys/cheat_engine.h

@@ -0,0 +1,226 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <map>
+#include <set>
+#include <vector>
+#include <queue>
+#include "common/bit_field.h"
+#include "common/common_types.h"
+
+namespace CoreTiming {
+struct EventType;
+}
+
+namespace FileSys {
+
+enum class CodeType : u32 {
+    // 0TMR00AA AAAAAAAA YYYYYYYY YYYYYYYY
+    // Writes a T sized value Y to the address A added to the value of register R in memory domain M
+    WriteImmediate = 0,
+
+    // 1TMC00AA AAAAAAAA YYYYYYYY YYYYYYYY
+    // Compares the T sized value Y to the value at address A in memory domain M using the
+    // conditional function C. If success, continues execution. If failure, jumps to the matching
+    // EndConditional statement.
+    Conditional = 1,
+
+    // 20000000
+    // Terminates a Conditional or ConditionalInput block.
+    EndConditional = 2,
+
+    // 300R0000 VVVVVVVV
+    // Starts looping V times, storing the current count in register R.
+    // Loop block is terminated with a matching 310R0000.
+    Loop = 3,
+
+    // 400R0000 VVVVVVVV VVVVVVVV
+    // Sets the value of register R to the value V.
+    LoadImmediate = 4,
+
+    // 5TMRI0AA AAAAAAAA
+    // Sets the value of register R to the value of width T at address A in memory domain M, with
+    // the current value of R added to the address if I == 1.
+    LoadIndexed = 5,
+
+    // 6T0RIFG0 VVVVVVVV VVVVVVVV
+    // Writes the value V of width T to the memory address stored in register R. Adds the value of
+    // register G to the final calculation if F is nonzero. Increments the value of register R by T
+    // after operation if I is nonzero.
+    StoreIndexed = 6,
+
+    // 7T0RA000 VVVVVVVV
+    // Performs the arithmetic operation A on the value in register R and the value V of width T,
+    // storing the result in register R.
+    RegisterArithmetic = 7,
+
+    // 8KKKKKKK
+    // Checks to see if any of the buttons defined by the bitmask K are pressed. If any are,
+    // execution continues. If none are, execution skips to the next EndConditional command.
+    ConditionalInput = 8,
+};
+
+enum class MemoryType : u32 {
+    // Addressed relative to start of main NSO
+    MainNSO = 0,
+
+    // Addressed relative to start of heap
+    Heap = 1,
+};
+
+enum class ArithmeticOp : u32 {
+    Add = 0,
+    Sub = 1,
+    Mult = 2,
+    LShift = 3,
+    RShift = 4,
+};
+
+enum class ComparisonOp : u32 {
+    GreaterThan = 1,
+    GreaterThanEqual = 2,
+    LessThan = 3,
+    LessThanEqual = 4,
+    Equal = 5,
+    Inequal = 6,
+};
+
+union Cheat {
+    std::array<u8, 16> raw;
+
+    BitField<4, 4, CodeType> type;
+    BitField<0, 4, u32> width; // Can be 1, 2, 4, or 8. Measured in bytes.
+    BitField<0, 4, u32> end_of_loop;
+    BitField<12, 4, MemoryType> memory_type;
+    BitField<8, 4, u32> register_3;
+    BitField<8, 4, ComparisonOp> comparison_op;
+    BitField<20, 4, u32> load_from_register;
+    BitField<20, 4, u32> increment_register;
+    BitField<20, 4, ArithmeticOp> arithmetic_op;
+    BitField<16, 4, u32> add_additional_register;
+    BitField<28, 4, u32> register_6;
+
+    u64 Address() const;
+    u64 ValueWidth(u64 offset) const;
+    u64 Value(u64 offset, u64 width) const;
+    u32 KeypadValue() const;
+};
+
+class CheatParser;
+
+// Represents a full collection of cheats for a game. The Execute function should be called every
+// interval that all cheats should be executed. Clients should not directly instantiate this class
+// (hence private constructor), they should instead receive an instance from CheatParser, which
+// guarantees the list is always in an acceptable state.
+class CheatList {
+public:
+    friend class CheatParser;
+
+    using Block = std::vector<Cheat>;
+    using ProgramSegment = std::vector<std::pair<std::string, Block>>;
+
+    // (width in bytes, address, value)
+    using MemoryWriter = void (*)(u8, VAddr, u64);
+    // (width in bytes, address) -> value
+    using MemoryReader = u64 (*)(u8, VAddr);
+
+    void SetMemoryParameters(VAddr main_begin, VAddr heap_begin, VAddr main_end, VAddr heap_end,
+                             MemoryWriter writer, MemoryReader reader);
+
+    void Execute();
+
+private:
+    CheatList(ProgramSegment master, ProgramSegment standard);
+
+    void ProcessBlockPairs(const Block& block);
+    void ExecuteSingleCheat(const Cheat& cheat);
+
+    void ExecuteBlock(const Block& block);
+
+    bool EvaluateConditional(const Cheat& cheat) const;
+
+    // Individual cheat operations
+    void WriteImmediate(const Cheat& cheat);
+    void BeginConditional(const Cheat& cheat);
+    void EndConditional(const Cheat& cheat);
+    void Loop(const Cheat& cheat);
+    void LoadImmediate(const Cheat& cheat);
+    void LoadIndexed(const Cheat& cheat);
+    void StoreIndexed(const Cheat& cheat);
+    void RegisterArithmetic(const Cheat& cheat);
+    void BeginConditionalInput(const Cheat& cheat);
+
+    VAddr SanitizeAddress(VAddr in) const;
+
+    // Master Codes are defined as codes that cannot be disabled and are run prior to all
+    // others.
+    ProgramSegment master_list;
+    // All other codes
+    ProgramSegment standard_list;
+
+    bool in_standard = false;
+
+    // 16 (0x0-0xF) scratch registers that can be used by cheats
+    std::array<u64, 16> scratch{};
+
+    MemoryWriter writer = nullptr;
+    MemoryReader reader = nullptr;
+
+    u64 main_region_begin{};
+    u64 heap_region_begin{};
+    u64 main_region_end{};
+    u64 heap_region_end{};
+
+    u64 current_block{};
+    // The current index of the cheat within the current Block
+    u64 current_index{};
+
+    // The 'stack' of the program. When a conditional or loop statement is encountered, its index is
+    // pushed onto this queue. When a end block is encountered, the condition is checked.
+    std::map<u64, u64> block_pairs;
+
+    std::set<u64> encountered_loops;
+};
+
+// Intermediary class that parses a text file or other disk format for storing cheats into a
+// CheatList object, that can be used for execution.
+class CheatParser {
+public:
+    virtual ~CheatParser();
+
+    virtual CheatList Parse(const std::vector<u8>& data) const = 0;
+
+protected:
+    CheatList MakeCheatList(CheatList::ProgramSegment master,
+                            CheatList::ProgramSegment standard) const;
+};
+
+// CheatParser implementation that parses text files
+class TextCheatParser final : public CheatParser {
+public:
+    ~TextCheatParser() override;
+
+    CheatList Parse(const std::vector<u8>& data) const override;
+
+private:
+    std::array<u8, 16> ParseSingleLineCheat(const std::string& line) const;
+};
+
+// Class that encapsulates a CheatList and manages its interaction with memory and CoreTiming
+class CheatEngine final {
+public:
+    CheatEngine(std::vector<CheatList> cheats, const std::string& build_id);
+    ~CheatEngine();
+
+private:
+    void FrameCallback(u64 userdata, int cycles_late);
+
+    CoreTiming::EventType* event;
+
+    std::vector<CheatList> cheats;
+};
+
+} // namespace FileSys