I have the following code which compiles with GCC using the flag -msse4
but the problem is that the pop count only gets the last four 8-bits of the converted __m128i
type. Basically what I want is to count all 16 numbers inside the __m128i
type but I'm not sure what intrinsic function call to make after creating the variable popA
. Somehow popA
has to be converted into an integer that contains all the 128-bits of information? I suppose theres _mm_cvtsi128_si64
and using a few shuffle few operations but my OS is 32-bit. Is there only the shuffle method and using _mm_cvtsi128_si32
?
EDIT: If the shuffle method is the only option I need help implementing it for my 32-bit OS, please.
Heres the code.
#include <stdio.h>
#include <smmintrin.h>
#include <emmintrin.h>
int main(void)
{
int A = 1;
__m128i popA = _mm_set_epi8( A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A);
unsigned int integer = _mm_cvtsi128_si32(popA);
//long long LONG = _mm_cvtsi128_si64(popA);//my OS is 32-bits so no luck here
printf("integer = %d\n", integer);
int pop = _mm_popcnt_u32(integer);
//int popLONG = _mm_popcnt_u64(LONG);
printf("popcount = %d\n", pop);
//printf("popcount LONG = %d\n", popLONG);
return 0;
}
EDIT 2: This one finally runs (with GCC compiler flags -msse -msse2 -msse3 -msse4
) although I'm not sure if the output for pop_count1()
is correct.
Output:
pop_count1(): 1799 1799 1799 1799 1799 1799 1799 1799
pop_count2():population count for each byte: 1 1 1 1 1 1 1 1 0 1 2 3 4 5 6 7
#include <stdio.h>
#include <xmmintrin.h>
#include <emmintrin.h>
#include <mmintrin.h>
#include <stdint.h>
#include <tmmintrin.h>
void print128_num(__m128i var)
{
uint16_t *val = (uint16_t*) &var;
printf("pop_count1(): %i %i %i %i %i %i %i %i \n",
val[0], val[1], val[2], val[3], val[4], val[5],
val[6], val[7]);
}
static __m128i parallelPopcnt16bytes (__m128i xmm)//for pop_count2
{
const __m128i mask4 = _mm_set1_epi8 (0x0F);
const __m128i lookup = _mm_setr_epi8 (0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4);
__m128i low, high, count;
low = _mm_and_si128 (mask4, xmm);
high = _mm_and_si128 (mask4, _mm_srli_epi16 (xmm, 4));
count = _mm_add_epi8 (_mm_shuffle_epi8 (lookup, low), _mm_shuffle_epi8 (lookup, high));
return count;
}
void pop_count1()
{
int A = 1;
__m128i in = _mm_set_epi8( A, A, A, A, A, A, A, A, A, A, A, A, A, A, A, A);
__m128i bit0 = _mm_set1_epi8( 0x80 );
__m128i mask0 = _mm_and_si128( in, bit0 );
__m128i sum = _mm_cmpeq_epi8( mask0, _mm_setzero_si128() );
/* general pattern */
__m128i bit1 = _mm_set1_epi8( 0x40 );
__m128i mask1 = _mm_and_si128( in, bit1 );
mask1 = _mm_cmpeq_epi8( mask1, _mm_setzero_si128() );
sum = _mm_add_epi8( sum, mask1 );
/* next bit */
__m128i bit2 = _mm_set1_epi8( 0x20 );
__m128i mask2 = _mm_and_si128( in, bit2 );
mask2 = _mm_cmpeq_epi8( mask2, _mm_setzero_si128() );
sum = _mm_add_epi8( sum, mask2 );
__m128i bit3 = _mm_set1_epi8( 0x10 );
__m128i mask3 = _mm_and_si128( in, bit3 );
mask3 = _mm_cmpeq_epi8( mask3, _mm_setzero_si128() );
sum = _mm_add_epi8( sum, mask3 );
__m128i bit4 = _mm_set1_epi8( 0x08 );
__m128i mask4 = _mm_and_si128( in, bit4 );
mask4 = _mm_cmpeq_epi8( mask4, _mm_setzero_si128() );
sum = _mm_add_epi8( sum, mask4 );
__m128i bit5 = _mm_set1_epi8( 0x04 );
__m128i mask5 = _mm_and_si128( in, bit5 );
mask5 = _mm_cmpeq_epi8( mask5, _mm_setzero_si128() );
sum = _mm_add_epi8( sum, mask5 );
__m128i bit6 = _mm_set1_epi8( 0x02 );
__m128i mask6 = _mm_and_si128( in, bit6 );
mask6 = _mm_cmpeq_epi8( mask6, _mm_setzero_si128() );
sum = _mm_add_epi8( sum, mask6 );
__m128i bit7 = _mm_set1_epi8( 0x01 );
__m128i mask7 = _mm_and_si128( in, bit7 );
mask7 = _mm_cmpeq_epi8( mask7, _mm_setzero_si128() );
sum = _mm_add_epi8( sum, mask7 );
/* finish up */
sum = _mm_sub_epi8( _mm_setzero_si128(), sum );
print128_num(sum);
}
void pop_count2()
{
int index;
__m128i testVector = _mm_set_epi8 (1, 2, 4, 8, 16, 32, 64, 128, 0, 1, 3, 7, 15, 31, 63, 127);
__m128i counts = parallelPopcnt16bytes (testVector);
printf ("pop_count2():population count for each byte:");
for (index = 15; index >= 0; index--)
{
uint8_t *bytes = (void *) &counts;
printf (" %d", bytes [index]);
}
printf ("\n");
}
int main(void)
{
pop_count1();
pop_count2();
return 0;
}