#include <stdio.h>

int main() {
  float a[] = { 1.0f, 2.0f, 3.0f, 4.0f }; 
  float b[] = { 1.1f, 2.2f, 3.3f, 4.4f };
  float s = 2.0f;

  for (int i = 0; i < 4; i++) printf("a[%d] = %f\n", i, a[i]);

  __asm {
    movups xmm1, a   ;//load 4 floats = 128 bit
    movups xmm2, b   ;//load 4 floats = 128 bit
    addps xmm1, xmm2 ;//add all 4 floats in parallel
    addss xmm1, s    ;//add scalar s to 1st float, 2nd - 4th float remain unchanged
    movups a, xmm1   ;//store into a
  }

  for (int i = 0; i < 4; i++) printf("a[%d] = %f\n", i, a[i]);
  return 0;
}