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srsLTE
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neon: add srslte_simd_b_neg() 

clang complained about an uinit var that is returned and it turned
out that we don't even implement that function in NEON.

I've found a nice MIT-licensed header that was easy to integrate.
This commit is contained in:
Andre Puschmann 2020-05-06 22:04:11 +02:00
parent 39fe760d2b
commit f67524707d
2 changed files with 38 additions and 8 deletions
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44
lib/include/srslte/phy/utils/simd.h
View File

@ -1548,9 +1548,25 @@ static inline simd_s_t srslte_simd_s_neg(simd_s_t a, simd_s_t b)
return _mm_sign_epi16(a, b);
#else /* LV_HAVE_SSE */
#ifdef HAVE_NEON
simd_s_t res;
return res;
//#error sign instruction not available in Neon
/* Taken and modified from sse2neon.h licensed under MIT
* Source: https://github.com/DLTcollab/sse2neon
*/
int16x8_t _a = vreinterpretq_s16_s32(a);
int16x8_t _b = vreinterpretq_s16_s32(b);
int16x8_t zero = vdupq_n_s16(0);
// signed shift right: faster than vclt
// (b < 0) ? 0xFFFF : 0
uint16x8_t ltMask = vreinterpretq_u16_s16(vshrq_n_s16(_b, 15));
// (b == 0) ? 0xFFFF : 0
int16x8_t zeroMask = vreinterpretq_s16_u16(vceqq_s16(_b, zero));
// -a
int16x8_t neg = vnegq_s16(_a);
// bitwise select either a or neg based on ltMask
int16x8_t masked = vbslq_s16(ltMask, _a, neg);
// res = masked & (~zeroMask)
int16x8_t res = vbicq_s16(masked, zeroMask);
return vreinterpretq_s32_s16(res);
#endif /* HAVE_NEON */
#endif /* LV_HAVE_SSE */
#endif /* LV_HAVE_AVX2 */
@ -2049,9 +2065,25 @@ static inline simd_s_t srslte_simd_b_neg(simd_b_t a, simd_b_t b)
return _mm_sign_epi8(a, b);
#else /* LV_HAVE_SSE */
#ifdef HAVE_NEON
simd_s_t res;
return res;
//#error sign instruction not available in Neon
/* Taken and modified from sse2neon.h licensed under MIT
* Source: https://github.com/DLTcollab/sse2neon
*/
int8x16_t _a = vreinterpretq_s8_s64(a);
int8x16_t _b = vreinterpretq_s8_s64(b);
int8x16_t zero = vdupq_n_s8(0);
// signed shift right: faster than vclt
// (b < 0) ? 0xFF : 0
uint8x16_t ltMask = vreinterpretq_u8_s8(vshrq_n_s8(_b, 7));
// (b == 0) ? 0xFF : 0
int8x16_t zeroMask = vreinterpretq_s8_u8(vceqq_s8(_b, zero));
// -a
int8x16_t neg = vnegq_s8(_a);
// bitwise select either a or neg based on ltMask
int8x16_t masked = vbslq_s8(ltMask, _a, neg);
// res = masked & (~zeroMask)
int8x16_t res = vbicq_s8(masked, zeroMask);
return vreinterpretq_s64_s8(res);
#endif /* HAVE_NEON */
#endif /* LV_HAVE_SSE */
#endif /* LV_HAVE_AVX2 */

2
lib/src/phy/utils/vector_simd.c
View File

@ -223,7 +223,6 @@ void srslte_vec_neg_sss_simd(const int16_t* x, const int16_t* y, int16_t* z, con
{
int i = 0;
#ifndef HAVE_NEON
#if SRSLTE_SIMD_S_SIZE
if (SRSLTE_IS_ALIGNED(x) && SRSLTE_IS_ALIGNED(y) && SRSLTE_IS_ALIGNED(z)) {
for (; i < len - SRSLTE_SIMD_S_SIZE + 1; i += SRSLTE_SIMD_S_SIZE) {
@ -245,7 +244,6 @@ void srslte_vec_neg_sss_simd(const int16_t* x, const int16_t* y, int16_t* z, con
}
}
#endif /* SRSLTE_SIMD_S_SIZE */
#endif /* NOT HAVE_NEON*/
for (; i < len; i++) {
z[i] = y[i] < 0 ? -x[i] : x[i];