C - How to access elements of vector using GCC SSE vector extension

Question

Usually I work with 3D vectors using following types:

typedef vec3_t float[3];

initializing vectors using smth. like:

vec3_         


        

Answer 1

You are forgetting that you need to reinterpret a as array of floats. Following code works properly:

int main(){
    v4sf a,b,c;
    a = (v4sf){0.1f,0.2f,0.3f,0.4f};
    b = (v4sf){0.1f,0.2f,0.3f,0.4f};
    c = (v4sf){0.1f,0.2f,0.3f,0.4f};
    a = b + c;
    float* pA = (float*) &a;
    printf("a=[%f %f %f %f]\n",pA[0], pA[1], pA[2], pA[3]);
    return 0;
}

P.S.: thanks for this question, I didn't know that gcc has such SSE support.

UPDATE: This solution fails once arrays got unaligned. Solution provided by @drhirsh is free from this problem.