wehub-resource-sync
96 lines
2.0 KiB
C
Executable File
96 lines
2.0 KiB
C
Executable File
#include <stdlib.h>
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#include <stdio.h>
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#include <signal.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <string.h>
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typedef struct { uint64_t state; uint64_t inc; } pcg32_random_t;
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uint32_t pcg32_random_r(pcg32_random_t* rng)
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{
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uint64_t oldstate = rng->state;
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// Advance internal state
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rng->state = oldstate * 6364136223846793005ULL + (rng->inc|1);
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// Calculate output function (XSH RR), uses old state for max ILP
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uint32_t xorshifted = ((oldstate >> 18u) ^ oldstate) >> 27u;
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uint32_t rot = oldstate >> 59u;
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return (xorshifted >> rot) | (xorshifted << ((-rot) & 31));
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}
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void pcg32_srandom_r(pcg32_random_t* rng, uint64_t initstate, uint64_t initseq)
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{
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rng->state = 0U;
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rng->inc = (initseq << 1u) | 1u;
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pcg32_random_r(rng);
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rng->state += initstate;
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pcg32_random_r(rng);
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}
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// static __inline__ uint64_t rdtsc(void)
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// {
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// unsigned hi, lo;
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// __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
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// return ( (uint64_t)lo)|( ((uint64_t)hi)<<32 );
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// }
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int my_do_work(pcg32_random_t *rng) {
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int res = 1;
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int i;
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for(i = 0; i < 70; i++) {
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int r = 0;
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int j;
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// for(j = 0; j < 3; j++) {
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r = (r + pcg32_random_r(rng)) % 2;
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// }
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if(r == 0) {
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res += 1;
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} else {
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int r2 = pcg32_random_r(rng) % 4;
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if(r2 == 0) {
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res -= 10;
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} else {
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res += r2;
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}
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}
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}
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return res;
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}
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int sim_busy_loop(pcg32_random_t *rng) {
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int res = 1;
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for(int i = 0; i < 100; i++) {
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int r = pcg32_random_r(rng) % 2;
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if(r == 0) {
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res += 1;
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} else {
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res -= 10;
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}
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}
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return res;
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}
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int
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main(int argc, char **argv) {
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// setup
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pcg32_random_t rng;
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pcg32_srandom_r(&rng, 42u, 54u);
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// pcg32_srandom_r(&rng, time(NULL) ^ (intptr_t)&printf, 54u);
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int res = 0;
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for(int i = 0; i < 10; i++) {
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sim_busy_loop(&rng);
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res += my_do_work(&rng);
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}
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// pid_t ppid = getppid();
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// kill(ppid, SIGUSR2);
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// fprintf(stderr, "ppid: %i\n", ppid);
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// sleep(1);
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printf("%i\n", res);
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return 0;
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}
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