Developer Guide and Reference

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Negation Intrinsics

These Supplemental Streaming SIMD Extensions 3 (SSSE3) intrinsics are used for negation. The prototypes for these intrinsics are in
tmmintrin.h
.
To use these intrinsics, include the
immintrin.h
file as follows:
#include <immintrin.h>

_mm_sign_epi8

extern __m128i _mm_sign_epi8(__m128i a, __m128i b);
Negates 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]; } }

_mm_sign_epi16

extern __m128i _mm_sign_epi16(__m128i a, __m128i b);
Negates 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]; } }

_mm_sign_epi32

extern __m128i _mm_sign_epi32(__m128i a, __m128i b);
Negates packed doublewords 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]; } }

_mm_sign_pi8

extern __m64 _mm_sign_pi8(__m64 a, __m64 b)