From bc1e43ea95b9455cdccee442db77bc5fafd3dcc6 Mon Sep 17 00:00:00 2001 From: David Monniaux Date: Tue, 26 May 2020 22:11:32 +0200 Subject: tests for kvx --- test/kvx/prng/prng.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 test/kvx/prng/prng.c (limited to 'test/kvx/prng/prng.c') diff --git a/test/kvx/prng/prng.c b/test/kvx/prng/prng.c new file mode 100644 index 00000000..71de1dc3 --- /dev/null +++ b/test/kvx/prng/prng.c @@ -0,0 +1,41 @@ +// https://en.wikipedia.org/wiki/Linear_congruential_generator -> MMIX Donald Knuth +// modulo 2^64 = no need to do it explicitly + +#include "types.h" + +#define MULTIPLIER 6364136223846793005LL +#define INCREMENT 1442695040888963407LL + +static uint64_t current; + +void srand(uint64_t seed){ + current = seed; +} + +uint64_t randlong(void){ + return (current = MULTIPLIER * current + INCREMENT); +} + +#ifdef __UNIT_TEST_PRNG__ +char bytewise_sum(uint64_t to_check){ + char sum = 0; + int i; + + for (i = 0 ; i < 8 ; i++) + sum += (to_check & (uint64_t)(0xFFULL << i*8)) >> i*8; + + return sum; +} + +int main(void){ + srand(42); + int i; + + for (i = 0 ; i < 1000 ; i++) + randlong(); + + uint64_t last = randlong(); + + return !((unsigned char)bytewise_sum(last) == 155); +} +#endif // __UNIT_TEST_PRNG__ -- cgit