source code
/* The Computer Language Benchmarks Game
* https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
contributed by Paolo Bonzini
further optimized by Jason Garrett-Glaser
pthreads added by Eckehard Berns
further optimized by Ryan Henszey
modified by Samy Al Bahra (use GCC atomic builtins)
modified by Kenneth Jonsson
*/
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
typedef double v2df __attribute__ ((vector_size(16))); /* vector of two doubles */
typedef int v4si __attribute__ ((vector_size(16))); /* vector of four ints */
/* 3 workers + the main thread to get a total of 4 active threads */
#define NWORKERS 3
int N;
int bytes_per_row;
double inverse_w;
double inverse_h;
const v2df zero = { 0.0, 0.0 };
const v2df four = { 4.0, 4.0 };
uint8_t *bitmap;
int next_y = 0;
static void * worker(void *_args) {
uint8_t *row_bitmap;
int x, y;
for (;;) {
y = __sync_fetch_and_add(&next_y, 1);
if (y >= N)
return NULL;
row_bitmap = bitmap + (bytes_per_row * y);
for (x=0; x<N; x+=2)
{
v2df Crv = { (x+1)*inverse_w-1.5, (x)*inverse_w-1.5 };
v2df Civ = { y*inverse_h-1.0, y*inverse_h-1.0 };
v2df Zrv = zero;
v2df Ziv = zero;
v2df Trv = zero;
v2df Tiv = zero;
int i = 0;
int two_pixels;
do {
Ziv = (Zrv*Ziv) + (Zrv*Ziv) + Civ;
Zrv = Trv - Tiv + Crv;
Trv = Zrv * Zrv;
Tiv = Ziv * Ziv;
/* from mandelbrot C++ GNU g++ #5 program */
v2df delta = (v2df)__builtin_ia32_cmplepd( (Trv + Tiv), four);
two_pixels = __builtin_ia32_movmskpd(delta);
} while (++i < 50 && two_pixels);
/*
* The pixel bits must be in the most and second most
* significant position
*/
two_pixels <<= 6;
/*
* Add the two pixels to the bitmap, all bits are
* initially zero since the area was allocated with
* calloc()
*/
row_bitmap[x >> 3] |= (uint8_t) (two_pixels >> (x & 7));
}
}
}
int main (int argc, char **argv)
{
pthread_t ids[NWORKERS];
int i;
N = atoi(argv[1]);
bytes_per_row = (N + 7) >> 3;
inverse_w = 2.0 / (bytes_per_row << 3);
inverse_h = 2.0 / N;
bitmap = calloc(bytes_per_row, N);
for (i = 0; i < NWORKERS; i++)
pthread_create(&ids[i], NULL, worker, NULL);
worker(NULL);
for (i = 0; i < NWORKERS; i++)
pthread_join(ids[i], NULL);
printf("P4\n%d %d\n", N, N);
fwrite(bitmap, bytes_per_row, N, stdout);
free(bitmap);
return 0;
}
notes, command-line, and program output
NOTES:
64-bit Ubuntu quad core
13.2.0-23ubuntu4
Mon, 03 Jun 2024 22:31:20 GMT
MAKE:
/usr/bin/gcc -pipe -Wall -O3 -fomit-frame-pointer -march=ivybridge -pthread mandelbrot.gcc-3.c -o mandelbrot.gcc-3.gcc_run -lm
rm mandelbrot.gcc-3.c
2.66s to complete and log all make actions
COMMAND LINE:
./mandelbrot.gcc-3.gcc_run 16000
(BINARY) PROGRAM OUTPUT NOT SHOWN