// SPDX-FileCopyrightText: 2019-2024 Connor McLaughlin <stenzek@gmail.com>
// SPDX-License-Identifier: (GPL-3.0 OR CC-BY-NC-ND-4.0)

#pragma once

#include "cpu_types.h"
#include "gte_types.h"
#include "types.h"

#include "common/bitfield.h"

#include <array>
#include <optional>
#include <string>
#include <vector>

class StateWrapper;

namespace CPU {

enum : VirtualMemoryAddress
{
  RESET_VECTOR = UINT32_C(0xBFC00000)
};
enum : PhysicalMemoryAddress
{
  SCRATCHPAD_ADDR = UINT32_C(0x1F800000),
  SCRATCHPAD_ADDR_MASK = UINT32_C(0x7FFFFC00),
  SCRATCHPAD_OFFSET_MASK = UINT32_C(0x000003FF),
  SCRATCHPAD_SIZE = UINT32_C(0x00000400),
  ICACHE_SIZE = UINT32_C(0x00001000),
  ICACHE_SLOTS = ICACHE_SIZE / sizeof(u32),
  ICACHE_LINE_SIZE = 16,
  ICACHE_LINES = ICACHE_SIZE / ICACHE_LINE_SIZE,
  ICACHE_SLOTS_PER_LINE = ICACHE_SLOTS / ICACHE_LINES,
  ICACHE_TAG_ADDRESS_MASK = 0xFFFFFFF0u,
  ICACHE_INVALID_BITS = 0x0Fu,
};

union CacheControl
{
  u32 bits;

  BitField<u32, bool, 0, 1> lock_mode;
  BitField<u32, bool, 1, 1> invalidate_mode;
  BitField<u32, bool, 2, 1> tag_test_mode;
  BitField<u32, bool, 3, 1> dcache_scratchpad;
  BitField<u32, bool, 7, 1> dcache_enable;
  BitField<u32, u8, 8, 2> icache_fill_size; // actually dcache? icache always fills to 16 bytes
  BitField<u32, bool, 11, 1> icache_enable;
};

struct PGXPValue
{
  float x;
  float y;
  float z;
  u32 value;
  u32 flags;

  ALWAYS_INLINE void Validate(u32 psxval) { flags = (value == psxval) ? flags : 0; }

  ALWAYS_INLINE float GetValidX(u32 psxval) const
  {
    return (flags & 1) ? x : static_cast<float>(static_cast<s16>(psxval));
  }
  ALWAYS_INLINE float GetValidY(u32 psxval) const
  {
    return (flags & 2) ? y : static_cast<float>(static_cast<s16>(psxval >> 16));
  }
};

struct State
{
  // ticks the CPU has executed
  u32 downcount = 0;
  u32 pending_ticks = 0;
  u32 gte_completion_tick = 0;

  Registers regs = {};
  Cop0Registers cop0_regs = {};

  u32 pc;  // at execution time: the address of the next instruction to execute (already fetched)
  u32 npc; // at execution time: the address of the next instruction to fetch

  // address of the instruction currently being executed
  Instruction current_instruction = {};
  u32 current_instruction_pc = 0;
  bool current_instruction_in_branch_delay_slot = false;
  bool current_instruction_was_branch_taken = false;
  bool next_instruction_is_branch_delay_slot = false;
  bool branch_was_taken = false;
  bool exception_raised = false;
  bool bus_error = false;

  // load delays
  Reg load_delay_reg = Reg::count;
  Reg next_load_delay_reg = Reg::count;
  u32 load_delay_value = 0;
  u32 next_load_delay_value = 0;

  Instruction next_instruction = {};
  CacheControl cache_control{0};

  // GTE registers are stored here so we can access them on ARM with a single instruction
  GTE::Regs gte_regs = {};

  // 2 bytes of padding here on x64
  bool using_interpreter = false;
  bool using_debug_dispatcher = false;

  void* fastmem_base = nullptr;
  void** memory_handlers = nullptr;

  PGXPValue pgxp_gpr[static_cast<u8>(Reg::count)] = {};
  PGXPValue pgxp_cop0[32] = {};
  PGXPValue pgxp_gte[64] = {};

  std::array<u32, ICACHE_LINES> icache_tags = {};
  std::array<u8, ICACHE_SIZE> icache_data = {};

  std::array<u8, SCRATCHPAD_SIZE> scratchpad = {};

  static constexpr u32 GPRRegisterOffset(u32 index) { return OFFSETOF(State, regs.r) + (sizeof(u32) * index); }
  static constexpr u32 GTERegisterOffset(u32 index) { return OFFSETOF(State, gte_regs.r32) + (sizeof(u32) * index); }
};

ALIGN_TO_CACHE_LINE extern State g_state;

void Initialize();
void Shutdown();
void Reset();
bool DoState(StateWrapper& sw);
void ClearICache();
bool UpdateDebugDispatcherFlag();
void UpdateMemoryPointers();
void ExecutionModeChanged();

/// Executes interpreter loop.
void Execute();

// Forces an early exit from the CPU dispatcher.
[[noreturn]] void ExitExecution();

ALWAYS_INLINE static Registers& GetRegs()
{
  return g_state.regs;
}

ALWAYS_INLINE static u32 GetPendingTicks()
{
  return g_state.pending_ticks;
}
ALWAYS_INLINE static void ResetPendingTicks()
{
  g_state.gte_completion_tick =
    (g_state.pending_ticks < g_state.gte_completion_tick) ? (g_state.gte_completion_tick - g_state.pending_ticks) : 0;
  g_state.pending_ticks = 0;
}
ALWAYS_INLINE static void AddPendingTicks(TickCount ticks)
{
  g_state.pending_ticks += static_cast<u32>(ticks);
}

// state helpers
ALWAYS_INLINE static bool InUserMode()
{
  return g_state.cop0_regs.sr.KUc;
}
ALWAYS_INLINE static bool InKernelMode()
{
  return !g_state.cop0_regs.sr.KUc;
}

// Memory reads variants which do not raise exceptions.
// These methods do not support writing to MMIO addresses with side effects, and are
// thus safe to call from the UI thread in debuggers, for example.
bool SafeReadMemoryByte(VirtualMemoryAddress addr, u8* value);
bool SafeReadMemoryHalfWord(VirtualMemoryAddress addr, u16* value);
bool SafeReadMemoryWord(VirtualMemoryAddress addr, u32* value);
bool SafeReadMemoryCString(VirtualMemoryAddress addr, std::string* value, u32 max_length = 1024);
bool SafeReadMemoryBytes(VirtualMemoryAddress addr, void* data, u32 length);
bool SafeWriteMemoryByte(VirtualMemoryAddress addr, u8 value);
bool SafeWriteMemoryHalfWord(VirtualMemoryAddress addr, u16 value);
bool SafeWriteMemoryWord(VirtualMemoryAddress addr, u32 value);
bool SafeWriteMemoryBytes(VirtualMemoryAddress addr, const void* data, u32 length);

// External IRQs
void SetIRQRequest(bool state);

void DisassembleAndPrint(u32 addr);
void DisassembleAndLog(u32 addr);
void DisassembleAndPrint(u32 addr, u32 instructions_before, u32 instructions_after);

// Write to CPU execution log file.
void WriteToExecutionLog(const char* format, ...) printflike(1, 2);

// Trace Routines
bool IsTraceEnabled();
void StartTrace();
void StopTrace();

// Breakpoint types - execute => breakpoint, read/write => watchpoints
enum class BreakpointType : u8
{
  Execute,
  Read,
  Write,
  Count
};

// Breakpoint callback - if the callback returns false, the breakpoint will be removed.
using BreakpointCallback = bool (*)(BreakpointType type, VirtualMemoryAddress pc, VirtualMemoryAddress memaddr);

struct Breakpoint
{
  VirtualMemoryAddress address;
  BreakpointCallback callback;
  u32 number;
  u32 hit_count;
  BreakpointType type;
  bool auto_clear;
  bool enabled;
};

using BreakpointList = std::vector<Breakpoint>;

// Breakpoints
const char* GetBreakpointTypeName(BreakpointType type);
bool HasAnyBreakpoints();
bool HasBreakpointAtAddress(BreakpointType type, VirtualMemoryAddress address);
BreakpointList CopyBreakpointList(bool include_auto_clear = false, bool include_callbacks = false);
bool AddBreakpoint(BreakpointType type, VirtualMemoryAddress address, bool auto_clear = false, bool enabled = true);
bool AddBreakpointWithCallback(BreakpointType type, VirtualMemoryAddress address, BreakpointCallback callback);
bool RemoveBreakpoint(BreakpointType type, VirtualMemoryAddress address);
void ClearBreakpoints();
bool AddStepOverBreakpoint();
bool AddStepOutBreakpoint(u32 max_instructions_to_search = 1000);
void SetSingleStepFlag();

extern bool TRACE_EXECUTION;

// Debug register introspection
struct DebuggerRegisterListEntry
{
  const char* name;
  u32* value_ptr;
};

static constexpr u32 NUM_DEBUGGER_REGISTER_LIST_ENTRIES = 103;
extern const std::array<DebuggerRegisterListEntry, NUM_DEBUGGER_REGISTER_LIST_ENTRIES> g_debugger_register_list;

} // namespace CPU
