printf("stddev:%3d.%02d bytes:%d\n", (int)(dev/F), (int)(dev%F), i);
printf("stddev:%3d.%02d PSNR:%2d.%02d bytes:%d\n", (int)(dev/F), (int)(dev%F), (int)(psnr/F), (int)(psnr%F), i);
int main(int argc,char* argv[]){    int i, j;    uint64_t sse=0;    uint64_t dev;    FILE *f[2];    uint8_t buf[2][SIZE];        if(argc!=3){        printf("tiny_psnr <file1> <file2>\n");        return -1;    }        f[0]= fopen(argv[1], "r");    f[1]= fopen(argv[2], "r");    for(i=0;;){        if( fread(buf[0], SIZE, 1, f[0]) != 1) break;        if( fread(buf[1], SIZE, 1, f[1]) != 1) break;                for(j=0; j<SIZE; i++,j++){            const int a= buf[0][j];            const int b= buf[1][j];            sse += (a-b) * (a-b);        }    }        dev= int_sqrt((sse*F*F)/i);        //FIXME someone should write a integer fixpoint log() function for bitexact PSNR scores ...    printf("stddev:%3d.%02d bytes:%d\n", (int)(dev/F), (int)(dev%F), i);        return 0;}