1 /* 2 * Benchmark support functions. 3 * 4 * Copyright (c) 2020, Arm Limited. 5 * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception 6 */ 7 8 #include <stdint.h> 9 #include <time.h> 10 11 /* Fast and accurate timer returning nanoseconds. */ 12 static inline uint64_t 13 clock_get_ns (void) 14 { 15 struct timespec ts; 16 clock_gettime (CLOCK_MONOTONIC, &ts); 17 return ts.tv_sec * (uint64_t) 1000000000 + ts.tv_nsec; 18 } 19 20 /* Fast 32-bit random number generator. Passing a non-zero seed 21 value resets the internal state. */ 22 static inline uint32_t 23 rand32 (uint32_t seed) 24 { 25 static uint64_t state = 0xb707be451df0bb19ULL; 26 if (seed != 0) 27 state = seed; 28 uint32_t res = state >> 32; 29 state = state * 6364136223846793005ULL + 1; 30 return res; 31 } 32 33 34