add right-shift function.

diff --git a/src/lib/util/uint128.h b/src/lib/util/uint128.h
index bcccb3a51d1d1031773753f6943420468e6d15ed..1d981cbc4914c65fc650d09ec4422d280dc2680d 100644 (file)
--- a/src/lib/util/uint128.h
+++ b/src/lib/util/uint128.h
@@ -201,6 +201,25 @@ static uint128_t uint128_lshift(uint128_t num, uint8_t bits)
        return num;
 }
 
+/** Right shift 128 bit integer
+ *
+ * @note shift must be 127 bits or less.
+ */
+static uint128_t uint128_rshift(uint128_t num, uint8_t bits)
+{
+       rad_assert(bits < 128);
+
+       if (bits >= 64) {
+               num.h = 0;
+               num.l = num.h >> (bits - 64);
+               return num;
+       }
+       num.l = (num.l >> bits) | (num.h << (64 - bits));
+       num.h >>= bits;
+
+       return num;
+}
+
 /** Perform bitwise & of two 128bit unsigned integers
  *
  */
@@ -261,6 +280,7 @@ static uint128_t uint128_new(uint64_t h, uint64_t l) {
 #define uint128_mul(_a, _b) ((_a) * (_b))
 
 #define uint128_lshift(_num, _bits) (_num << _bits)
+#define uint128_rshift(_num, _bits) (_num >> _bits)
 #define uint128_band(_a, _b) (_a & _b)
 #define uint128_bor(_a, _b) (_a | _b)