1 files changed, 109 insertions, 0 deletions
diff --git a/platform/linux-generic/odp_random_std.c b/platform/linux-generic/odp_random_std.c
new file mode 100644
index 000000000..5ae47d596
--- /dev/null
+++ b/platform/linux-generic/odp_random_std.c
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (c) 2014-2018 Linaro Limited
+ */
+
+#include <odp/api/byteorder.h>
+#include <odp/api/cpu.h>
+#include <odp/api/debug.h>
+#include <odp_init_internal.h>
+#include <odp_random_std_internal.h>
+#include <odp_cpu.h>
+
+#include <stdint.h>
+#include <time.h>
+
+/*
+ * Xorshift64*, adapted from [1], and modified to return only the high 32 bits.
+ *
+ * [1] An experimental exploration of Marsaglia's xorshift generators, scrambled
+ *     Sebastiano Vigna, July 2016.
+ *     http://vigna.di.unimi.it/ftp/papers/xorshift.pdf
+ */
+static inline uint32_t xorshift64s32(uint64_t *x)
+{
+	/* The variable x should be initialized to a nonzero seed. [1] */
+	if (!*x)
+		/*
+		 * 2^64 / phi. As far away as possible from any small integer
+		 * fractions, which the caller might be likely to use for the
+		 * next seed after 0.
+		 */
+		*x = 11400714819323198485ull;
+
+	*x ^= *x >> 12; /* a */
+	*x ^= *x << 25; /* b */
+	*x ^= *x >> 27; /* c */
+	return (*x * 2685821657736338717ull) >> 32;
+}
+
+static int32_t _random_data(uint8_t *buf, uint32_t len, uint64_t *seed)
+{
+	const uint32_t ret = len;
+
+	if (!_ODP_UNALIGNED) {
+		uint32_t r = xorshift64s32(seed);
+
+		if (((uintptr_t)buf & 1) && len) {
+			*(uint8_t *)buf = r & 0xff;
+			r >>= 8;
+			buf += 1;
+			len -= 1;
+		}
+
+		if (((uintptr_t)buf & 2) && len >= 2) {
+			*(uint16_t *)(uintptr_t)buf = r & 0xffff;
+			buf += 2;
+			len -= 2;
+		}
+
+		for (uint32_t i = 0; i < len / 4; i++) {
+			*(uint32_t *)(uintptr_t)buf = xorshift64s32(seed);
+			buf += 4;
+		}
+	} else {
+		for (uint32_t i = 0; i < len / 4; i++) {
+			*(odp_una_u32_t *)buf = xorshift64s32(seed);
+			buf += 4;
+		}
+	}
+
+	if (len & 3) {
+		uint32_t r = xorshift64s32(seed);
+
+		if (len & 2) {
+			*(odp_una_u16_t *)buf = r & 0xffff;
+			r >>= 16;
+			buf += 2;
+		}
+
+		if (len & 1)
+			*(uint8_t *)buf = r & 0xff;
+	}
+
+	return ret;
+}
+
+int32_t _odp_random_std_test_data(uint8_t *buf, uint32_t len, uint64_t *seed)
+{
+	return _random_data(buf, len, seed);
+}
+
+static __thread uint64_t this_seed;
+
+int32_t _odp_random_std_data(uint8_t *buf, uint32_t len)
+{
+	return _random_data(buf, len, &this_seed);
+}
+
+int _odp_random_std_init_local(void)
+{
+	this_seed = time(NULL);
+	this_seed ^= (uint64_t)odp_cpu_id() << 32;
+
+	return 0;
+}
+
+int _odp_random_std_term_local(void)
+{
+	return 0;
+}