main.cpp

#include <arm_neon.h>




void add3 (uint8x16_t *data) {
    /* Set each sixteen values of the vector to 3.
     *
     * Remark: a 'q' suffix to intrinsics indicates
     * the instruction run for 128 bits registers.
     */
    uint8x16_t three = vmovq_n_u8 (3);

    /* Add 3 to the value given in argument. */
    *data = vaddq_u8 (*data, three);
}

void print_uint8 (uint8x16_t data, char* name) {
    int i;
    static uint8_t p[16];

    vst1q_u8 (p, data);

    printf ("%s = ", name);
    for (i = 0; i < 16; i++) {
	printf ("%02d ", p[i]);
    }
    printf ("\n");
}

int main () {
    /* Create custom arbitrary data. */
    const uint8_t uint8_data[] = { 1, 2, 3, 4, 5, 6, 7, 8,
				   9, 10, 11, 12, 13, 14, 15, 16 };

    /* Create the vector with our data. */
    uint8x16_t data;

    /* Load our custom data into the vector register. */
    data = vld1q_u8 (uint8_data);

    print_uint8 (data, "data");
    
    /* Call of the add3 function. */
    add3(&data);

    print_uint8 (data, "data (new)");
    
    return 0;
}