#ifndef COSMOPOLITAN_TOOL_BUILD_LIB_FLAGS_H_
#define COSMOPOLITAN_TOOL_BUILD_LIB_FLAGS_H_

#define FLAGS_CF   0
#define FLAGS_VF   1
#define FLAGS_PF   2
#define FLAGS_F1   3
#define FLAGS_AF   4
#define FLAGS_KF   5
#define FLAGS_ZF   6
#define FLAGS_SF   7
#define FLAGS_TF   8
#define FLAGS_IF   9
#define FLAGS_DF   10
#define FLAGS_OF   11
#define FLAGS_IOPL 12
#define FLAGS_NT   14
#define FLAGS_F0   15
#define FLAGS_RF   16
#define FLAGS_VM   17
#define FLAGS_AC   18
#define FLAGS_VIF  19
#define FLAGS_VIP  20
#define FLAGS_ID   21

#define GetLazyParityBool(f)    GetParity((f) >> 24)
#define SetLazyParityByte(f, x) (((f) & ~0xFF000000u) | ((x)&0xFF) << 24)

#define GetParity(WORD)     \
  ({                        \
    unsigned Byte = (WORD); \
    Byte ^= Byte >> 4;      \
    Byte ^= Byte >> 2;      \
    Byte ^= Byte >> 1;      \
    ~Byte & 1;              \
  })

#define GetFlag(FLAGS, BIT)               \
  ({                                      \
    autotype(FLAGS) Flags = (FLAGS);      \
    typeof(Flags) IsSet;                  \
    switch (BIT) {                        \
      case FLAGS_PF:                      \
        IsSet = GetLazyParityBool(Flags); \
        break;                            \
      default:                            \
        IsSet = (Flags >> (BIT)) & 1;     \
        break;                            \
    }                                     \
    IsSet;                                \
  })

#define SetFlag(FLAGS, BIT, VAL)                          \
  ({                                                      \
    autotype(FLAGS) Flags = (FLAGS);                      \
    typeof(Flags) Val = (VAL);                            \
    typeof(Flags) One = 1;                                \
    switch (BIT) {                                        \
      case FLAGS_PF:                                      \
        Flags = SetLazyParityByte(Flags, !Val);           \
        break;                                            \
      default:                                            \
        Flags = (Flags & ~(One << (BIT))) | Val << (BIT); \
        break;                                            \
    }                                                     \
    Flags;                                                \
  })

forceinline uint64_t ExportFlags(uint64_t flags) {
  flags = SetFlag(flags, FLAGS_IOPL, 3);
  flags = SetFlag(flags, FLAGS_F1, true);
  flags = SetFlag(flags, FLAGS_F0, false);
  flags = flags & ~(1ull << FLAGS_PF);
  flags |= GetLazyParityBool(flags) << FLAGS_PF;
  return flags;
}

#endif /* COSMOPOLITAN_TOOL_BUILD_LIB_FLAGS_H_ */