1 files changed, 149 insertions, 0 deletions
diff --git a/src/include/qemu/int128.h b/src/include/qemu/int128.h
new file mode 100644
index 0000000..fb782aa
--- /dev/null
+++ b/src/include/qemu/int128.h
@@ -0,0 +1,149 @@
+#ifndef INT128_H
+#define INT128_H
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef struct Int128 Int128;
+
+struct Int128 {
+    uint64_t lo;
+    int64_t hi;
+};
+
+static inline Int128 int128_make64(uint64_t a)
+{
+    return (Int128) { a, 0 };
+}
+
+static inline uint64_t int128_get64(Int128 a)
+{
+    assert(!a.hi);
+    return a.lo;
+}
+
+static inline Int128 int128_zero(void)
+{
+    return int128_make64(0);
+}
+
+static inline Int128 int128_one(void)
+{
+    return int128_make64(1);
+}
+
+static inline Int128 int128_2_64(void)
+{
+    return (Int128) { 0, 1 };
+}
+
+static inline Int128 int128_exts64(int64_t a)
+{
+    return (Int128) { .lo = a, .hi = (a < 0) ? -1 : 0 };
+}
+
+static inline Int128 int128_and(Int128 a, Int128 b)
+{
+    return (Int128) { a.lo & b.lo, a.hi & b.hi };
+}
+
+static inline Int128 int128_rshift(Int128 a, int n)
+{
+    int64_t h;
+    if (!n) {
+        return a;
+    }
+    h = a.hi >> (n & 63);
+    if (n >= 64) {
+        return (Int128) { h, h >> 63 };
+    } else {
+        return (Int128) { (a.lo >> n) | ((uint64_t)a.hi << (64 - n)), h };
+    }
+}
+
+static inline Int128 int128_add(Int128 a, Int128 b)
+{
+    uint64_t lo = a.lo + b.lo;
+
+    /* a.lo <= a.lo + b.lo < a.lo + k (k is the base, 2^64).  Hence,
+     * a.lo + b.lo >= k implies 0 <= lo = a.lo + b.lo - k < a.lo.
+     * Similarly, a.lo + b.lo < k implies a.lo <= lo = a.lo + b.lo < k.
+     *
+     * So the carry is lo < a.lo.
+     */
+    return (Int128) { lo, (uint64_t)a.hi + b.hi + (lo < a.lo) };
+}
+
+static inline Int128 int128_neg(Int128 a)
+{
+    uint64_t lo = -a.lo;
+    return (Int128) { lo, ~(uint64_t)a.hi + !lo };
+}
+
+static inline Int128 int128_sub(Int128 a, Int128 b)
+{
+    return (Int128){ a.lo - b.lo, (uint64_t)a.hi - b.hi - (a.lo < b.lo) };
+}
+
+static inline bool int128_nonneg(Int128 a)
+{
+    return a.hi >= 0;
+}
+
+static inline bool int128_eq(Int128 a, Int128 b)
+{
+    return a.lo == b.lo && a.hi == b.hi;
+}
+
+static inline bool int128_ne(Int128 a, Int128 b)
+{
+    return !int128_eq(a, b);
+}
+
+static inline bool int128_ge(Int128 a, Int128 b)
+{
+    return a.hi > b.hi || (a.hi == b.hi && a.lo >= b.lo);
+}
+
+static inline bool int128_lt(Int128 a, Int128 b)
+{
+    return !int128_ge(a, b);
+}
+
+static inline bool int128_le(Int128 a, Int128 b)
+{
+    return int128_ge(b, a);
+}
+
+static inline bool int128_gt(Int128 a, Int128 b)
+{
+    return !int128_le(a, b);
+}
+
+static inline bool int128_nz(Int128 a)
+{
+    return a.lo || a.hi;
+}
+
+static inline Int128 int128_min(Int128 a, Int128 b)
+{
+    return int128_le(a, b) ? a : b;
+}
+
+static inline Int128 int128_max(Int128 a, Int128 b)
+{
+    return int128_ge(a, b) ? a : b;
+}
+
+static inline void int128_addto(Int128 *a, Int128 b)
+{
+    *a = int128_add(*a, b);
+}
+
+static inline void int128_subfrom(Int128 *a, Int128 b)
+{
+    *a = int128_sub(*a, b);
+}
+
+#endif