int popcount5(unsigned* array, int len)
{
     int i;
     int val, result = 0;
     int SSE_mask[] = { 0x0f0f0f0f, 0x0f0f0f0f, 0x0f0f0f0f, 0x0f0f0f0f };
     int SSE_LUTb[] = { 0x02010100, 0x03020201, 0x03020201, 0x04030302 };

     if (len & 0x3)
	printf("leyendo 128b pero len no múltiplo de 4\n");
     for (i = 0; i < len; i += 4) {
        asm( "movdqu    %[x], %%xmm0 \n\t"
             "movdqa  %%xmm0, %%xmm1 \n\t" // dos copias de x
             "movdqu    %[m], %%xmm6 \n\t"// máscara
             "psrlw       $4, %%xmm1 \n\t"
             "pand    %%xmm6, %%xmm0 \n\t"//; xmm0 – nibbles inferiores
             "pand    %%xmm6, %%xmm1 \n\t"//; xmm1 – nibbles superiores

             "movdqu    %[l], %%xmm2 \n\t"//; ...como pshufb sobrescribe LUT
             "movdqa  %%xmm2, %%xmm3 \n\t"//; ...queremos 2 copias
             "pshufb  %%xmm0, %%xmm2 \n\t"//; xmm2 = vector popcount inferiores
             "pshufb  %%xmm1, %%xmm3 \n\t"//; xmm3 = vector popcount superiores

             "paddb   %%xmm2, %%xmm3 \n\t"//; xmm3 - vector popcount bytes
             "pxor    %%xmm0, %%xmm0 \n\t"//; xmm0 = 0,0,0,0
             "psadbw  %%xmm0, %%xmm3 \n\t"//;xmm3 = [pcnt bytes0..7|pcnt bytes8..15]
             "movhlps %%xmm3, %%xmm0 \n\t"//;xmm3 = [             0           |pcnt bytes0..7 ]
             "paddd   %%xmm3, %%xmm0 \n\t"//;xmm0 = [ no usado        |pcnt bytes0..15]
             "movd    %%xmm0, %[val] \n\t"
             : [val]"=r" (val)
             : [x] "m" (array[i]),
             [m] "m" (SSE_mask[0]),
             [l] "m" (SSE_LUTb[0])
	);
        result += val;
     }
     return result;
}