Negation Intrinsics

These Intel® Supplemental Streaming SIMD Extensions 3 (Intel® SSSE3) intrinsics are used for negation. The prototypes for these intrinsics are in tmmintrin.h. You can also use the ia32intrin.h header file for these intrinsics.

extern __m128i _mm_sign_epi8 (__m128i a, __m128i b);

Negate packed bytes in a if corresponding sign in b is less than zero.

Interpreting a, b, and r as arrays of signed 8-bit integers:

for (i = 0; i < 16; i++){

 if (b[i] < 0){

  r[i] = -a[i];

 }

 else

 if (b[i] == 0){

  r[i] = 0;

 }

 else

 {

  r[i] = a[i];

 }

}

extern __m128i _mm_sign_epi16 (__m128i a, __m128i b);

Negate packed words in a if corresponding sign in b is less than zero.

Interpreting a, b, and r as arrays of signed 16-bit integers:

for (i = 0; i < 8; i++){

 if (b[i] < 0){

  r[i] = -a[i];

 }

 else

 if (b[i] == 0){

  r[i] = 0;

 }

 else

 {

  r[i] = a[i];

 }

}

extern __m128i _mm_sign_epi32 (__m128i a, __m128i b);

Negate packed dwords in a if corresponding sign in b is less than zero.

Interpreting a, b, and r as arrays of signed 32-bit integers:

for (i = 0; i < 4; i++){

 if (b[i] < 0){

  r[i] = -a[i];

 }

 else

 if (b[i] == 0){

  r[i] = 0;

 }

 else

 {

  r[i] = a[i];

 }

}

extern __m64 _mm_sign_pi8 (__m64 a, __m64 b);

Negate packed bytes in a if corresponding sign in b is less than zero.

Interpreting a, b, and r as arrays of signed 8-bit integers:

for (i = 0; i < 16; i++){

 if (b[i] < 0){

  r[i] = -a[i];

 }

 else

 if (b[i] == 0){

  r[i] = 0;

 }

 else

 {

  r[i] = a[i];

 }

}

extern __m64 _mm_sign_pi16 (__m64 a, __m64 b);

Negate packed words in a if corresponding sign in b is less than zero.

Interpreting a, b, and r as arrays of signed 16-bit integers:

for (i = 0; i < 8; i++){

 if (b[i] < 0){

  r[i] = -a[i];

 }

 else

 if (b[i] == 0){

  r[i] = 0;

 }

 else

 {

  r[i] = a[i];

 }

}

extern __m64 _mm_sign_pi32 (__m64 a, __m64 b);

Negate packed dwords in a if corresponding sign in b is less than zero.

Interpreting a, b, and r as arrays of signed 32-bit integers:

for (i = 0; i < 2; i++){

 if (b[i] < 0){

  r[i] = -a[i];

 }

 else

 if (b[i] == 0){

  r[i] = 0;

 }

 else

 {

  r[i] = a[i];

 }

}