int128.h

   1 #ifndef INT128_H
   2 #define INT128_H
   3
   4 typedef struct Int128 Int128;
   5
   6 struct Int128 {
   7     uint64_t lo;
   8     int64_t hi;
   9 };
  10
  11 static inline Int128 int128_make64(uint64_t a)
  12 {
  13     return (Int128) { a, 0 };
  14 }
  15
  16 static inline uint64_t int128_get64(Int128 a)
  17 {
  18     assert(!a.hi);
  19     return a.lo;
  20 }
  21
  22 static inline Int128 int128_zero(void)
  23 {
  24     return int128_make64(0);
  25 }
  26
  27 static inline Int128 int128_one(void)
  28 {
  29     return int128_make64(1);
  30 }
  31
  32 static inline Int128 int128_2_64(void)
  33 {
  34     return (Int128) { 0, 1 };
  35 }
  36
  37 static inline Int128 int128_add(Int128 a, Int128 b)
  38 {
  39     Int128 r = { a.lo + b.lo, a.hi + b.hi };
  40     r.hi += (r.lo < a.lo) || (r.lo < b.lo);
  41     return r;
  42 }
  43
  44 static inline Int128 int128_neg(Int128 a)
  45 {
  46     a.lo = ~a.lo;
  47     a.hi = ~a.hi;
  48     return int128_add(a, int128_one());
  49 }
  50
  51 static inline Int128 int128_sub(Int128 a, Int128 b)
  52 {
  53     return int128_add(a, int128_neg(b));
  54 }
  55
  56 static inline bool int128_nonneg(Int128 a)
  57 {
  58     return a.hi >= 0;
  59 }
  60
  61 static inline bool int128_eq(Int128 a, Int128 b)
  62 {
  63     return a.lo == b.lo && a.hi == b.hi;
  64 }
  65
  66 static inline bool int128_ne(Int128 a, Int128 b)
  67 {
  68     return !int128_eq(a, b);
  69 }
  70
  71 static inline bool int128_ge(Int128 a, Int128 b)
  72 {
  73     return int128_nonneg(int128_sub(a, b));
  74 }
  75
  76 static inline bool int128_lt(Int128 a, Int128 b)
  77 {
  78     return !int128_ge(a, b);
  79 }
  80
  81 static inline bool int128_le(Int128 a, Int128 b)
  82 {
  83     return int128_ge(b, a);
  84 }
  85
  86 static inline bool int128_gt(Int128 a, Int128 b)
  87 {
  88     return !int128_le(a, b);
  89 }
  90
  91 static inline bool int128_nz(Int128 a)
  92 {
  93     return a.lo || a.hi;
  94 }
  95
  96 static inline Int128 int128_min(Int128 a, Int128 b)
  97 {
  98     return int128_le(a, b) ? a : b;
  99 }
 100
 101 static inline Int128 int128_max(Int128 a, Int128 b)
 102 {
 103     return int128_ge(a, b) ? a : b;
 104 }
 105
 106 static inline void int128_addto(Int128 *a, Int128 b)
 107 {
 108     *a = int128_add(*a, b);
 109 }
 110
 111 static inline void int128_subfrom(Int128 *a, Int128 b)
 112 {
 113     *a = int128_sub(*a, b);
 114 }
 115
 116 #endif