+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2017 Cavium, Inc
+ */
/*
* Reciprocal divide
*
uint8_t sh1, sh2;
};
+struct rte_reciprocal_u64 {
+ uint64_t m;
+ uint8_t sh1, sh2;
+};
+
static inline uint32_t rte_reciprocal_divide(uint32_t a, struct rte_reciprocal R)
{
uint32_t t = (uint32_t)(((uint64_t)a * R.m) >> 32);
return (t + ((a - t) >> R.sh1)) >> R.sh2;
}
+static __rte_always_inline uint64_t
+mullhi_u64(uint64_t x, uint64_t y)
+{
+#ifdef __SIZEOF_INT128__
+ __uint128_t xl = x;
+ __uint128_t rl = xl * y;
+
+ return (rl >> 64);
+#else
+ uint64_t u0, u1, v0, v1, k, t;
+ uint64_t w1, w2;
+ uint64_t whi;
+
+ u1 = x >> 32; u0 = x & 0xFFFFFFFF;
+ v1 = y >> 32; v0 = y & 0xFFFFFFFF;
+
+ t = u0*v0;
+ k = t >> 32;
+
+ t = u1*v0 + k;
+ w1 = t & 0xFFFFFFFF;
+ w2 = t >> 32;
+
+ t = u0*v1 + w1;
+ k = t >> 32;
+
+ whi = u1*v1 + w2 + k;
+
+ return whi;
+#endif
+}
+
+static __rte_always_inline uint64_t
+rte_reciprocal_divide_u64(uint64_t a, const struct rte_reciprocal_u64 *R)
+{
+ uint64_t t = mullhi_u64(a, R->m);
+
+ return (t + ((a - t) >> R->sh1)) >> R->sh2;
+}
+
struct rte_reciprocal rte_reciprocal_value(uint32_t d);
+struct rte_reciprocal_u64 rte_reciprocal_value_u64(uint64_t d);
#endif /* _RTE_RECIPROCAL_H_ */