1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Simple xorshift PRNG 4 * see http://www.jstatsoft.org/v08/i14/paper 5 * 6 * Copyright (c) 2012 Michael Walle 7 * Michael Walle <michael@walle.cc> 8 */ 9 10 #include <common.h> 11 12 static unsigned int y = 1U; 13 14 unsigned int rand_r(unsigned int *seedp) 15 { 16 *seedp ^= (*seedp << 13); 17 *seedp ^= (*seedp >> 17); 18 *seedp ^= (*seedp << 5); 19 20 return *seedp; 21 } 22 23 unsigned int rand(void) 24 { 25 return rand_r(&y); 26 } 27 28 void srand(unsigned int seed) 29 { 30 y = seed; 31 } 32