converting four floats in xmm3 to four ints in memory

Question

I am newbie to sse, and I have trouble to find it, please tell me what is the good way to convert (truncate as in "(int) float_") four packed floats I have in xmm3 register into four ints and store it into memory (some like "movaps oword [edx+32], xmm3 " storing is clear but i do not find just how to convert)

Answer 1

Use intrinsics if you value your sanity (and free time):

int32_t *dest;
__m128 vf = _mm_set_ps(4.0f, 3.0f, 2.0f, 1.0f);
__m128i vi = _mm_cvttps_epi32(vf); // 4 x float -> 4 x int (with truncation)
_mm_store_epi32(dest, vi); // NB: use _mm_storeu_epi32 if `dest` not aligned

If you must use asm for some reason the the corresponding instruction for _mm_cvttps_epi32 is cvttps2dq.