diff options
Diffstat (limited to 'source/wy_random.c')
| -rw-r--r-- | source/wy_random.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/source/wy_random.c b/source/wy_random.c new file mode 100644 index 0000000..dcec829 --- /dev/null +++ b/source/wy_random.c @@ -0,0 +1,105 @@ +/* MIT License - Copyright (c) 2025 wallstop + * Original C# implementation from: https://github.com/wallstop/unity-helpers + * Converted to C for librandom project + * + * @BAKE cc -O2 -Wall -Wextra -std=c99 -o wy_random wy_random.c -lm @STOP + */ + +#include "wy_random.h" + +#define WY_PRIME0 0xa0761d6478bd642fULL +#define WY_PRIME1 0xe7037ed1a0b428dbULL + +/* Multiply two 64-bit integers and return hi and lo parts of 128-bit result */ +static inline void multiply_64(uint64_t x, uint64_t y, uint64_t *hi, uint64_t *lo) { + uint64_t x0 = (uint32_t)x; + uint64_t x1 = x >> 32; + uint64_t y0 = (uint32_t)y; + uint64_t y1 = y >> 32; + + uint64_t p11 = x1 * y1; + uint64_t p01 = x0 * y1; + uint64_t p10 = x1 * y0; + uint64_t p00 = x0 * y0; + + uint64_t middle = p10 + (p00 >> 32) + (uint32_t)p01; + + *lo = (middle << 32) | (uint32_t)p00; + *hi = p11 + (middle >> 32) + (p01 >> 32); +} + +/* MUM (MUltiply and Mix) operation */ +static inline uint64_t mum(uint64_t x, uint64_t y) { + uint64_t hi, lo; + multiply_64(x, y, &hi, &lo); + return hi ^ lo; +} + +void wy_init(wy_random_t *rng, uint64_t seed) { + rng->state = seed; +} + +uint32_t wy_next_uint(wy_random_t *rng) { + rng->state += WY_PRIME0; + return (uint32_t)mum(rng->state ^ WY_PRIME1, rng->state); +} + +uint64_t wy_next_ulong(wy_random_t *rng) { + rng->state += WY_PRIME0; + return mum(rng->state ^ WY_PRIME1, rng->state); +} + +float wy_next_float(wy_random_t *rng) { + uint32_t value = wy_next_uint(rng); + return (value >> 8) * 0x1.0p-24f; +} + +double wy_next_double(wy_random_t *rng) { + uint64_t value = wy_next_ulong(rng); + return (value >> 11) * 0x1.0p-53; +} + +#ifdef WY_TEST_MAIN +#include <stdio.h> +#include <time.h> + +int main(void) { + wy_random_t rng; + + printf("WyRandom C Implementation Test\n"); + printf("===============================\n\n"); + + wy_init(&rng, 42); + + printf("Testing with seed 42:\n"); + printf("First 10 uint32_t values:\n"); + for (int i = 0; i < 10; i++) { + printf(" %u\n", wy_next_uint(&rng)); + } + + printf("\nFirst 10 uint64_t values:\n"); + wy_init(&rng, 42); + for (int i = 0; i < 10; i++) { + printf(" %llu\n", (unsigned long long)wy_next_ulong(&rng)); + } + + printf("\nFirst 10 float values:\n"); + wy_init(&rng, 42); + for (int i = 0; i < 10; i++) { + printf(" %.6f\n", wy_next_float(&rng)); + } + + printf("\nPerformance test: generating 10 million uint64_t values...\n"); + wy_init(&rng, (uint64_t)time(NULL)); + clock_t start = clock(); + uint64_t sum = 0; + for (int i = 0; i < 10000000; i++) { + sum += wy_next_ulong(&rng); + } + clock_t end = clock(); + double elapsed = (double)(end - start) / CLOCKS_PER_SEC; + printf("Time: %.3f seconds (sum: %llu to prevent optimization)\n", elapsed, (unsigned long long)sum); + + return 0; +} +#endif |
