kaizen/src/backend/core/registers/Cop0.hpp

#pragma once
#include <common.hpp>
#include <log.hpp>
#include <unordered_map>

namespace n64 {
#define STATUS_MASK 0xFF57FFFF
#define CONFIG_MASK 0x0F00800F
#define INDEX_MASK 0x8000003F
#define COP0_REG_INDEX 0
#define COP0_REG_RANDOM 1
#define COP0_REG_ENTRYLO0 2
#define COP0_REG_ENTRYLO1 3
#define COP0_REG_CONTEXT 4
#define COP0_REG_PAGEMASK 5
#define COP0_REG_WIRED 6
#define COP0_REG_BADVADDR 8
#define COP0_REG_COUNT 9
#define COP0_REG_ENTRYHI 10
#define COP0_REG_COMPARE 11
#define COP0_REG_STATUS 12
#define COP0_REG_CAUSE 13
#define COP0_REG_EPC 14
#define COP0_REG_PRID 15
#define COP0_REG_CONFIG 16
#define COP0_REG_LLADDR 17
#define COP0_REG_WATCHLO 18
#define COP0_REG_WATCHHI 19
#define COP0_REG_XCONTEXT 20
#define COP0_REG_PARITY_ERR 26
#define COP0_REG_CACHE_ERR 27
#define COP0_REG_TAGLO 28
#define COP0_REG_TAGHI 29
#define COP0_REG_ERROREPC 30

#define ENTRY_LO_MASK 0x3FFFFFFF
#define ENTRY_HI_MASK 0xC00000FFFFFFE0FF
#define PAGEMASK_MASK 0x1FFE000

union Cop0Cause {
  u32 raw;
  struct {
    unsigned : 8;
    unsigned interruptPending : 8;
    unsigned : 16;
  } __attribute__((__packed__));
  struct {
    unsigned : 2;
    unsigned exceptionCode : 5;
    unsigned : 1;
    unsigned ip0 : 1;
    unsigned ip1 : 1;
    unsigned ip2 : 1;
    unsigned ip3 : 1;
    unsigned ip4 : 1;
    unsigned ip5 : 1;
    unsigned ip6 : 1;
    unsigned ip7 : 1;
    unsigned : 12;
    unsigned copError : 2;
    unsigned : 1;
    unsigned branchDelay : 1;
  } __attribute__((__packed__));
};

union Cop0Status {
  struct {
    unsigned ie : 1;
    unsigned exl : 1;
    unsigned erl : 1;
    unsigned ksu : 2;
    unsigned ux : 1;
    unsigned sx : 1;
    unsigned kx : 1;
    unsigned im : 8;
    unsigned ds : 9;
    unsigned re : 1;
    unsigned fr : 1;
    unsigned rp : 1;
    unsigned cu0 : 1;
    unsigned cu1 : 1;
    unsigned cu2 : 1;
    unsigned cu3 : 1;
  } __attribute__((__packed__));
  struct {
    unsigned : 16;
    unsigned de : 1;
    unsigned ce : 1;
    unsigned ch : 1;
    unsigned : 1;
    unsigned sr : 1;
    unsigned ts : 1;
    unsigned bev : 1;
    unsigned : 1;
    unsigned its : 1;
    unsigned : 7;
  } __attribute__((__packed__));
  u32 raw;
} __attribute__((__packed__));

union EntryLo {
  u32 raw;
  struct {
    unsigned g : 1;
    unsigned v : 1;
    unsigned d : 1;
    unsigned c : 3;
    unsigned pfn : 20;
    unsigned : 6;
  };
};

union EntryHi {
  u64 raw;
  struct {
    u64 asid : 8;
    u64 : 5;
    u64 vpn2 : 27;
    u64 fill : 22;
    u64 r : 2;
  } __attribute__((__packed__));
};

union PageMask {
  u32 raw;
  struct {
    unsigned : 13;
    unsigned mask : 12;
    unsigned : 7;
  };
};

union Index {
  u32 raw;
  struct {
    unsigned i : 6;
    unsigned : 25;
    unsigned p : 1;
  };
};

struct TLBEntry {
  bool initialized;
  EntryLo entryLo0, entryLo1;
  EntryHi entryHi;
  PageMask pageMask;

  bool global;
};

enum TLBError : u8 { NONE, MISS, INVALID, MODIFICATION, DISALLOWED_ADDRESS };

enum class ExceptionCode : u8 {
  Interrupt = 0,
  TLBModification = 1,
  TLBLoad = 2,
  TLBStore = 3,
  AddressErrorLoad = 4,
  AddressErrorStore = 5,
  InstructionBusError = 6,
  DataBusError = 7,
  Syscall = 8,
  Breakpoint = 9,
  ReservedInstruction = 10,
  CoprocessorUnusable = 11,
  Overflow = 12,
  Trap = 13,
  FloatingPointError = 15,
  Watch = 23
};

union Cop0Context {
  u64 raw;
  struct {
    u64 : 4;
    u64 badvpn2 : 19;
    u64 ptebase : 41;
  };
};

union Cop0XContext {
  u64 raw;
  struct {
    u64 : 4;
    u64 badvpn2 : 27;
    u64 r : 2;
    u64 ptebase : 31;
  } __attribute__((__packed__));
};

struct Cop0 {
  Cop0();

  u32 GetReg32(u8);
  [[nodiscard]] u64 GetReg64(u8) const;

  void SetReg32(u8, u32);
  void SetReg64(u8, u64);

  void Reset();

  bool kernelMode{true};
  bool supervisorMode{false};
  bool userMode{false};
  bool is64BitAddressing{false};
  bool llbit{};

  PageMask pageMask{};
  EntryHi entryHi{};
  EntryLo entryLo0{}, entryLo1{};
  Index index{};
  Cop0Context context{};
  u32 wired{}, r7{};
  u64 badVaddr{}, count{};
  u32 compare{};
  Cop0Status status{};
  Cop0Cause cause{};
  s64 EPC{};
  u32 PRId{}, Config{}, LLAddr{}, WatchLo{}, WatchHi{};
  Cop0XContext xcontext{};
  u32 r21{}, r22{}, r23{}, r24{}, r25{}, ParityError{}, CacheError{}, TagLo{}, TagHi{};
  s64 ErrorEPC{};
  u32 r31{};
  TLBEntry tlb[32]{};
  TLBError tlbError = NONE;
  s64 openbus{};

  [[nodiscard]] FORCE_INLINE u32 GetRandom() const {
    u32 val = rand();
    const auto wired_ = GetWired();
    u32 lower, upper;
    if (wired_ > 31) {
      lower = 0;
      upper = 64;
    } else {
      lower = wired_;
      upper = 32 - wired_;
    }

    val = (val % upper) + lower;
    return val;
  }

  FORCE_INLINE void Update() {
    const bool exception = status.exl || status.erl;

    kernelMode = exception || status.ksu == 0;
    supervisorMode = !exception && status.ksu == 1;
    userMode = !exception && status.ksu == 2;
    is64BitAddressing = (kernelMode && status.kx) || (supervisorMode && status.sx) || (userMode && status.ux);
  }

  enum TLBAccessType { LOAD, STORE };

  bool ProbeTLB(TLBAccessType accessType, u64 vaddr, u32 &paddr);
  void FireException(ExceptionCode code, int cop, s64 pc);
  bool MapVAddr(TLBAccessType accessType, u64 vaddr, u32 &paddr);
  bool UserMapVAddr32(TLBAccessType accessType, u64 vaddr, u32 &paddr);
  bool MapVAddr32(TLBAccessType accessType, u64 vaddr, u32 &paddr);
  bool UserMapVAddr64(TLBAccessType accessType, u64 vaddr, u32 &paddr);
  bool MapVAddr64(TLBAccessType accessType, u64 vaddr, u32 &paddr);

  TLBEntry *TLBTryMatch(u64 vaddr, int &index);
  TLBEntry *TLBTryMatch(u64 vaddr);
  void HandleTLBException(u64 vaddr);
  static ExceptionCode GetTLBExceptionCode(TLBError error, TLBAccessType accessType);
  void decode(u32);

private:
  [[nodiscard]] FORCE_INLINE u32 GetWired() const { return wired & 0x3F; }
  [[nodiscard]] FORCE_INLINE u32 GetCount() const { return u32(u64(count >> 1)); }

  void mtc0(u32);
  void dmtc0(u32);
  void mfc0(u32);
  void dmfc0(u32) const;
  void eret();

  void tlbr();
  void tlbw(int);
  void tlbp();
};
} // namespace n64