#include <stddef.h>
#include <stdint.h>

#define CACHELINESIZE 64
#define THRESHOLD 200

unsigned measureflush(void *table, size_t tablesize, uint8_t *bitmap)
{
    size_t i;
    uint32_t t1;
    uint32_t t2;
    unsigned int bit;
    unsigned int n_hits = 0;

    for (i = 0; i < tablesize / CACHELINESIZE; i++) {
        __asm__ volatile (
          " xor %%rax, %%rax           \n"
          " cpuid                      \n"
          " rdtsc                      \n"
          " mov %%eax, %%edi           \n"
          " mov (%[flushaddr]), %%rbx  \n"
          " xor %%rax, %%rax           \n"
          " cpuid                      \n"
          " rdtsc                      \n"
          " clflush (%[flushaddr])     \n"
          : "=a"(t2), "=D"(t1)
          : [flushaddr] "r"((const char *)table + (CACHELINESIZE * i))
          : "rbx", "rcx", "rdx", "cc");
        bit = (t2 - t1 < THRESHOLD) ? 1 : 0;
        n_hits += bit;
        bitmap[i / 8] &= ~(1 << (i % 8));
        bitmap[i / 8] |= bit << (i % 8);
    }

    return n_hits;
}