#include <stdio.h>
#include <sys/mman.h>
#include <string.h>
#include <sys/time.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(void)
{
        int f;
        unsigned long int *mem,*src,*dst;
        int t;
        long int usecs;
        unsigned long int secs, count;
        double rate;
        struct timeval tv, tv0, tv1;

        printf("Opening fb0\n");
        f = open("/dev/fb0", O_RDWR);
        if(f<0) {
                perror("opening fb0");
                return 1;
        }
        printf("mmapping fb0\n");

        mem = mmap(NULL, 0x00300000, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_LOCKED,f,0);

        printf("mmap returned: %08x\n",(unsigned int)mem);
        perror("mmap");
        if(mem==-1)
                return 1;

        gettimeofday(&tv, NULL);
        for(t=0; t<0x000c0000; t++)
                mem[t] = (tv.tv_usec ^ tv.tv_sec) ^ t;
        count = 0;
        gettimeofday(&tv0, NULL);
        for(t=0; t<10; t++) {
                src = mem;
                dst = mem+0x00040000;
                memcpy(dst, src, 0x00100000);
                count += 0x00100000;
        }
        gettimeofday(&tv1, NULL);
        secs = tv1.tv_sec-tv0.tv_sec;
        usecs = tv1.tv_usec-tv0.tv_usec;
        if(usecs<0) {
                usecs += 1000000;
                secs -= 1;
        }
        printf("Time elapsed: %ld secs, %ld usecs data transferred: %ld bytes\n",secs, usecs, count);
        rate = (double)count/((double)secs + (double)usecs/1000000.0);
        printf("Data rate: %5.3g MiB/s\n", rate/(1024.0*1024.0));

        return 0;
}