[hamradio-commits] [gnss-sdr] 157/236: Fixing NEON proto-kernels
Carles Fernandez
carles_fernandez-guest at moszumanska.debian.org
Tue Apr 26 16:02:47 UTC 2016
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carles_fernandez-guest pushed a commit to branch next
in repository gnss-sdr.
commit a5fb34c800b6545a4e4d8e7af310ab7fa6652e20
Author: Carles Fernandez <carles.fernandez at gmail.com>
Date: Sun Apr 3 02:27:54 2016 +0200
Fixing NEON proto-kernels
---
.../volk_gnsssdr_16ic_xn_resampler2_16ic_xn.h | 240 ++++++++++++++++++---
.../volk_gnsssdr_32fc_xn_resampler_32fc_xn.h | 11 +-
2 files changed, 222 insertions(+), 29 deletions(-)
diff --git a/src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/kernels/volk_gnsssdr/volk_gnsssdr_16ic_xn_resampler2_16ic_xn.h b/src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/kernels/volk_gnsssdr/volk_gnsssdr_16ic_xn_resampler2_16ic_xn.h
index f460b64..51216eb 100644
--- a/src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/kernels/volk_gnsssdr/volk_gnsssdr_16ic_xn_resampler2_16ic_xn.h
+++ b/src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/kernels/volk_gnsssdr/volk_gnsssdr_16ic_xn_resampler2_16ic_xn.h
@@ -1,12 +1,12 @@
/*!
- * \file volk_gnsssdr_16ic_xn_resampler_16ic_xn.h
+ * \file volk_gnsssdr_16ic_xn_resampler2_16ic_xn.h
* \brief VOLK_GNSSSDR kernel: Resamples N 16 bits integer short complex vectors using zero hold resample algorithm.
* \authors <ul>
* <li> Javier Arribas, 2015. jarribas(at)cttc.es
* </ul>
*
- * VOLK_GNSSSDR kernel that esamples N 16 bits integer short complex vectors using zero hold resample algorithm.
- * It is optimized to resample a sigle GNSS local code signal replica into N vectors fractional-resampled and fractional-delayed
+ * VOLK_GNSSSDR kernel that resamples N 16 bits integer short complex vectors using zero hold resample algorithm.
+ * It resamples a single GNSS local code signal replica into N vectors fractional-resampled and fractional-delayed
* (i.e. it creates the Early, Prompt, and Late code replicas)
*
* -------------------------------------------------------------------------
@@ -35,7 +35,7 @@
*/
/*!
- * \page volk_gnsssdr_16ic_xn_resampler_16ic_xn
+ * \page volk_gnsssdr_16ic_xn_resampler2_16ic_xn
*
* \b Overview
*
@@ -43,13 +43,14 @@
*
* <b>Dispatcher Prototype</b>
* \code
- * void volk_gnsssdr_16ic_xn_resampler_16ic_xn(lv_16sc_t** result, const lv_16sc_t* local_code, float* rem_code_phase_chips, float code_phase_step_chips, unsigned int code_length_chips, int num_out_vectors, unsigned int num_output_samples)
+ * void volk_gnsssdr_16ic_xn_resampler2_16ic_xn(lv_16sc_t** result, const lv_16sc_t* local_code, float* rem_code_phase_chips, float code_phase_step_chips, float* shifts_chips, unsigned int code_length_chips, int num_out_vectors, unsigned int num_output_samples)
* \endcode
*
* \b Inputs
* \li local_code: One of the vectors to be multiplied.
* \li rem_code_phase_chips: Remnant code phase [chips].
* \li code_phase_step_chips: Phase increment per sample [chips/sample].
+ * \li shifts_chips: Vector of floats that defines the spacing (in chips) between the replicas of \p local_code
* \li code_length_chips: Code length in chips.
* \li num_out_vectors Number of output vectors.
* \li num_output_samples: The number of data values to be in the resampled vector.
@@ -149,6 +150,7 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_sse4_1(lv_16sc_t**
}
}
}
+
#endif
@@ -156,7 +158,61 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_sse4_1(lv_16sc_t**
#include <smmintrin.h>
static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_u_sse4_1(lv_16sc_t** result, const lv_16sc_t* local_code, float rem_code_phase_chips, float code_phase_step_chips, float* shifts_chips, unsigned int code_length_chips, int num_out_vectors, unsigned int num_output_samples)
{
- volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_sse4_1(result, local_code, rem_code_phase_chips, code_phase_step_chips, shifts_chips, code_length_chips, num_out_vectors, num_output_samples);
+ lv_16sc_t** _result = result;
+ const unsigned int quarterPoints = num_output_samples / 4;
+
+ const __m128 fours = _mm_set1_ps(4.0f);
+ const __m128 rem_code_phase_chips_reg = _mm_set_ps1(rem_code_phase_chips);
+ const __m128 code_phase_step_chips_reg = _mm_set_ps1(code_phase_step_chips);
+
+ __VOLK_ATTR_ALIGNED(16) int local_code_chip_index[4];
+ int local_code_chip_index_;
+
+ const __m128i zeros = _mm_setzero_si128();
+ const __m128 code_length_chips_reg_f = _mm_set_ps1((float)code_length_chips);
+ const __m128i code_length_chips_reg_i = _mm_set1_epi32((int)code_length_chips);
+ __m128i local_code_chip_index_reg, aux_i, negatives, i;
+ __m128 aux, aux2, shifts_chips_reg, c, cTrunc, base;
+
+ for (int current_correlator_tap = 0; current_correlator_tap < num_out_vectors; current_correlator_tap++)
+ {
+ shifts_chips_reg = _mm_set_ps1((float)shifts_chips[current_correlator_tap]);
+ aux2 = _mm_sub_ps(shifts_chips_reg, rem_code_phase_chips_reg);
+ __m128 indexn = _mm_set_ps(3.0f, 2.0f, 1.0f, 0.0f);
+ for(unsigned int n = 0; n < quarterPoints; n++)
+ {
+ aux = _mm_mul_ps(code_phase_step_chips_reg, indexn);
+ aux = _mm_add_ps(aux, aux2);
+ // floor
+ aux = _mm_floor_ps(aux);
+
+ // fmod
+ c = _mm_div_ps(aux, code_length_chips_reg_f);
+ i = _mm_cvttps_epi32(c);
+ cTrunc = _mm_cvtepi32_ps(i);
+ base = _mm_mul_ps(cTrunc, code_length_chips_reg_f);
+ local_code_chip_index_reg = _mm_cvtps_epi32(_mm_sub_ps(aux, base));
+
+ negatives = _mm_cmplt_epi32(local_code_chip_index_reg, zeros);
+ aux_i = _mm_and_si128(code_length_chips_reg_i, negatives);
+ local_code_chip_index_reg = _mm_add_epi32(local_code_chip_index_reg, aux_i);
+ _mm_store_si128((__m128i*)local_code_chip_index, local_code_chip_index_reg);
+ for(unsigned int k = 0; k < 4; ++k)
+ {
+ _result[current_correlator_tap][n * 4 + k] = local_code[local_code_chip_index[k]];
+ }
+ indexn = _mm_add_ps(indexn, fours);
+ }
+ for(unsigned int n = quarterPoints * 4; n < num_output_samples; n++)
+ {
+ // resample code for current tap
+ local_code_chip_index_ = (int)floor(code_phase_step_chips * (float)n + shifts_chips[current_correlator_tap] - rem_code_phase_chips);
+ local_code_chip_index_ = local_code_chip_index_ % code_length_chips;
+ //Take into account that in multitap correlators, the shifts can be negative!
+ if (local_code_chip_index_ < 0) local_code_chip_index_ += code_length_chips;
+ _result[current_correlator_tap][n] = local_code[local_code_chip_index_];
+ }
+ }
}
#endif
@@ -190,6 +246,7 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_sse3(lv_16sc_t** re
__m128 indexn = _mm_set_ps(3.0f, 2.0f, 1.0f, 0.0f);
for(unsigned int n = 0; n < quarterPoints; n++)
{
+ //__builtin_prefetch(&_result[current_correlator_tap][4 * n] + 8, 1, 0);
aux = _mm_mul_ps(code_phase_step_chips_reg, indexn);
aux = _mm_add_ps(aux, aux2);
// floor
@@ -217,6 +274,7 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_sse3(lv_16sc_t** re
}
for(unsigned int n = quarterPoints * 4; n < num_output_samples; n++)
{
+ //__builtin_prefetch(&_result[current_correlator_tap][n] + 2, 1, 0);
// resample code for current tap
local_code_chip_index_ = (int)floor(code_phase_step_chips * (float)n + shifts_chips[current_correlator_tap] - rem_code_phase_chips);
local_code_chip_index_ = local_code_chip_index_ % code_length_chips;
@@ -234,7 +292,68 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_sse3(lv_16sc_t** re
#include <pmmintrin.h>
static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_u_sse3(lv_16sc_t** result, const lv_16sc_t* local_code, float rem_code_phase_chips, float code_phase_step_chips, float* shifts_chips, unsigned int code_length_chips, int num_out_vectors, unsigned int num_output_samples)
{
- volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_sse3(result, local_code, rem_code_phase_chips, code_phase_step_chips, shifts_chips, code_length_chips, num_out_vectors, num_output_samples);
+ lv_16sc_t** _result = result;
+ const unsigned int quarterPoints = num_output_samples / 4;
+
+ const __m128 ones = _mm_set1_ps(1.0f);
+ const __m128 fours = _mm_set1_ps(4.0f);
+ const __m128 rem_code_phase_chips_reg = _mm_set_ps1(rem_code_phase_chips);
+ const __m128 code_phase_step_chips_reg = _mm_set_ps1(code_phase_step_chips);
+
+ __VOLK_ATTR_ALIGNED(16) int local_code_chip_index[4];
+ int local_code_chip_index_;
+
+ const __m128i zeros = _mm_setzero_si128();
+ const __m128 code_length_chips_reg_f = _mm_set_ps1((float)code_length_chips);
+ const __m128i code_length_chips_reg_i = _mm_set1_epi32((int)code_length_chips);
+ __m128i local_code_chip_index_reg, aux_i, negatives, i;
+ __m128 aux, aux2, shifts_chips_reg, fi, igx, j, c, cTrunc, base;
+
+ for (int current_correlator_tap = 0; current_correlator_tap < num_out_vectors; current_correlator_tap++)
+ {
+ shifts_chips_reg = _mm_set_ps1((float)shifts_chips[current_correlator_tap]);
+ aux2 = _mm_sub_ps(shifts_chips_reg, rem_code_phase_chips_reg);
+ __m128 indexn = _mm_set_ps(3.0f, 2.0f, 1.0f, 0.0f);
+ for(unsigned int n = 0; n < quarterPoints; n++)
+ {
+ //__builtin_prefetch(&_result[current_correlator_tap][4 * n + 3], 1, 0);
+ //__builtin_prefetch(&local_code_chip_index[4]);
+ aux = _mm_mul_ps(code_phase_step_chips_reg, indexn);
+ aux = _mm_add_ps(aux, aux2);
+ // floor
+ i = _mm_cvttps_epi32(aux);
+ fi = _mm_cvtepi32_ps(i);
+ igx = _mm_cmpgt_ps(fi, aux);
+ j = _mm_and_ps(igx, ones);
+ aux = _mm_sub_ps(fi, j);
+ // fmod
+ c = _mm_div_ps(aux, code_length_chips_reg_f);
+ i = _mm_cvttps_epi32(c);
+ cTrunc = _mm_cvtepi32_ps(i);
+ base = _mm_mul_ps(cTrunc, code_length_chips_reg_f);
+ local_code_chip_index_reg = _mm_cvtps_epi32(_mm_sub_ps(aux, base));
+
+ negatives = _mm_cmplt_epi32(local_code_chip_index_reg, zeros);
+ aux_i = _mm_and_si128(code_length_chips_reg_i, negatives);
+ local_code_chip_index_reg = _mm_add_epi32(local_code_chip_index_reg, aux_i);
+ _mm_store_si128((__m128i*)local_code_chip_index, local_code_chip_index_reg);
+ for(unsigned int k = 0; k < 4; ++k)
+ {
+ _result[current_correlator_tap][n * 4 + k] = local_code[local_code_chip_index[k]];
+ }
+ indexn = _mm_add_ps(indexn, fours);
+ }
+ for(unsigned int n = quarterPoints * 4; n < num_output_samples; n++)
+ {
+ //__builtin_prefetch(&_result[current_correlator_tap][n], 1, 0);
+ // resample code for current tap
+ local_code_chip_index_ = (int)floor(code_phase_step_chips * (float)n + shifts_chips[current_correlator_tap] - rem_code_phase_chips);
+ local_code_chip_index_ = local_code_chip_index_ % code_length_chips;
+ //Take into account that in multitap correlators, the shifts can be negative!
+ if (local_code_chip_index_ < 0) local_code_chip_index_ += code_length_chips;
+ _result[current_correlator_tap][n] = local_code[local_code_chip_index_];
+ }
+ }
}
#endif
@@ -267,6 +386,8 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_avx(lv_16sc_t** res
__m256 indexn = _mm256_set_ps(7.0f, 6.0f, 5.0f, 4.0f, 3.0f, 2.0f, 1.0f, 0.0f);
for(unsigned int n = 0; n < avx_iters; n++)
{
+ __builtin_prefetch(&_result[current_correlator_tap][8 * n + 7], 1, 0);
+ __builtin_prefetch(&local_code_chip_index[8]);
aux = _mm256_mul_ps(code_phase_step_chips_reg, indexn);
aux = _mm256_add_ps(aux, aux2);
// floor
@@ -289,10 +410,15 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_avx(lv_16sc_t** res
}
indexn = _mm256_add_ps(indexn, eights);
}
+ }
+ _mm256_zeroupper();
+ for (int current_correlator_tap = 0; current_correlator_tap < num_out_vectors; current_correlator_tap++)
+ {
for(unsigned int n = avx_iters * 8; n < num_output_samples; n++)
{
// resample code for current tap
+ __builtin_prefetch(&_result[current_correlator_tap][n], 1, 0);
local_code_chip_index_ = (int)floor(code_phase_step_chips * (float)n + shifts_chips[current_correlator_tap] - rem_code_phase_chips);
local_code_chip_index_ = local_code_chip_index_ % code_length_chips;
//Take into account that in multitap correlators, the shifts can be negative!
@@ -300,7 +426,6 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_avx(lv_16sc_t** res
_result[current_correlator_tap][n] = local_code[local_code_chip_index_];
}
}
- _mm256_zeroupper();
}
#endif
@@ -310,7 +435,66 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_avx(lv_16sc_t** res
#include <immintrin.h>
static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_u_avx(lv_16sc_t** result, const lv_16sc_t* local_code, float rem_code_phase_chips, float code_phase_step_chips, float* shifts_chips, unsigned int code_length_chips, int num_out_vectors, unsigned int num_output_samples)
{
- volk_gnsssdr_16ic_xn_resampler2_16ic_xn_a_avx(result, local_code, rem_code_phase_chips, code_phase_step_chips, shifts_chips, code_length_chips, num_out_vectors, num_output_samples);
+ lv_16sc_t** _result = result;
+ const unsigned int avx_iters = num_output_samples / 8;
+
+ const __m256 eights = _mm256_set1_ps(8.0f);
+ const __m256 rem_code_phase_chips_reg = _mm256_set1_ps(rem_code_phase_chips);
+ const __m256 code_phase_step_chips_reg = _mm256_set1_ps(code_phase_step_chips);
+
+ __VOLK_ATTR_ALIGNED(32) int local_code_chip_index[8];
+ int local_code_chip_index_;
+
+ const __m256 zeros = _mm256_setzero_ps();
+ const __m256 code_length_chips_reg_f = _mm256_set1_ps((float)code_length_chips);
+
+ __m256i local_code_chip_index_reg, i;
+ __m256 aux, aux2, shifts_chips_reg, c, cTrunc, base, negatives;
+
+ for (int current_correlator_tap = 0; current_correlator_tap < num_out_vectors; current_correlator_tap++)
+ {
+ shifts_chips_reg = _mm256_set1_ps((float)shifts_chips[current_correlator_tap]);
+ aux2 = _mm256_sub_ps(shifts_chips_reg, rem_code_phase_chips_reg);
+ __m256 indexn = _mm256_set_ps(7.0f, 6.0f, 5.0f, 4.0f, 3.0f, 2.0f, 1.0f, 0.0f);
+ for(unsigned int n = 0; n < avx_iters; n++)
+ {
+ aux = _mm256_mul_ps(code_phase_step_chips_reg, indexn);
+ aux = _mm256_add_ps(aux, aux2);
+ // floor
+ aux = _mm256_floor_ps(aux);
+
+ // fmod
+ c = _mm256_div_ps(aux, code_length_chips_reg_f);
+ i = _mm256_cvttps_epi32(c);
+ cTrunc = _mm256_cvtepi32_ps(i);
+ base = _mm256_mul_ps(cTrunc, code_length_chips_reg_f);
+ aux = _mm256_sub_ps(aux, base);
+
+ negatives = _mm256_cmp_ps(aux, zeros, 0x01);
+ aux2 = _mm256_and_ps(code_length_chips_reg_f, negatives);
+ local_code_chip_index_reg = _mm256_cvtps_epi32(_mm256_add_ps(aux, aux2));
+
+ _mm256_store_si256((__m256i*)local_code_chip_index, local_code_chip_index_reg);
+ for(unsigned int k = 0; k < 8; ++k)
+ {
+ _result[current_correlator_tap][n * 8 + k] = local_code[local_code_chip_index[k]];
+ }
+ indexn = _mm256_add_ps(indexn, eights);
+ }
+ }
+ _mm256_zeroupper();
+ for (int current_correlator_tap = 0; current_correlator_tap < num_out_vectors; current_correlator_tap++)
+ {
+ for(unsigned int n = avx_iters * 8; n < num_output_samples; n++)
+ {
+ // resample code for current tap
+ local_code_chip_index_ = (int)floor(code_phase_step_chips * (float)n + shifts_chips[current_correlator_tap] - rem_code_phase_chips);
+ local_code_chip_index_ = local_code_chip_index_ % code_length_chips;
+ //Take into account that in multitap correlators, the shifts can be negative!
+ if (local_code_chip_index_ < 0) local_code_chip_index_ += code_length_chips;
+ _result[current_correlator_tap][n] = local_code[local_code_chip_index_];
+ }
+ }
}
#endif
@@ -318,7 +502,6 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_u_avx(lv_16sc_t** res
#ifdef LV_HAVE_NEON
#include <arm_neon.h>
-#include <volk_gnsssdr/volk_gnsssdr_neon_intrinsics.h>
static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_neon(lv_16sc_t** result, const lv_16sc_t* local_code, float rem_code_phase_chips, float code_phase_step_chips, float* shifts_chips, unsigned int code_length_chips, int num_out_vectors, unsigned int num_output_samples)
{
lv_16sc_t** _result = result;
@@ -328,26 +511,26 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_neon(lv_16sc_t** resu
const float32x4_t rem_code_phase_chips_reg = vdupq_n_f32(rem_code_phase_chips);
const float32x4_t code_phase_step_chips_reg = vdupq_n_f32(code_phase_step_chips);
- __attribute__((aligned(16))) int local_code_chip_index[4];
- int local_code_chip_index_;
-
+ __VOLK_ATTR_ALIGNED(16) int32_t local_code_chip_index[4];
+ int32_t local_code_chip_index_;
const int32x4_t zeros = vdupq_n_s32(0);
const float32x4_t code_length_chips_reg_f = vdupq_n_f32((float)code_length_chips);
- const int32x4_t code_length_chips_reg_i = vdupq_n_s32((int)code_length_chips);
+
+ const int32x4_t code_length_chips_reg_i = vdupq_n_s32((int32_t)code_length_chips);
int32x4_t local_code_chip_index_reg, aux_i, negatives, i;
- float32x4_t aux, aux2, shifts_chips_reg, fi, c, j, cTrunc, base;
- __attribute__((aligned(16))) float vec[4] = { 3.0f, 2.0f, 1.0f, 0.0f };
+ float32x4_t aux, aux2, shifts_chips_reg, fi, c, j, cTrunc, base, indexn, reciprocal;
+ __VOLK_ATTR_ALIGNED(16) const float vec[4] = { 0.0f, 1.0f, 2.0f, 3.0f };
uint32x4_t igx;
- float32x4_t half = vdupq_n_f32(0.5f);
- float32x4_t sign, PlusHalf, Round;
+
for (int current_correlator_tap = 0; current_correlator_tap < num_out_vectors; current_correlator_tap++)
{
shifts_chips_reg = vdupq_n_f32((float)shifts_chips[current_correlator_tap]);
aux2 = vsubq_f32(shifts_chips_reg, rem_code_phase_chips_reg);
- float32x4_t indexn = vld1q_f32((float*)vec);
-
+ indexn = vld1q_f32((float*)vec);
for(unsigned int n = 0; n < neon_iters; n++)
{
+ __builtin_prefetch(&_result[current_correlator_tap][4 * n + 3], 1, 0);
+ __builtin_prefetch(&local_code_chip_index[4]);
aux = vmulq_f32(code_phase_step_chips_reg, indexn);
aux = vaddq_f32(aux, aux2);
// floor
@@ -358,20 +541,21 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_neon(lv_16sc_t** resu
aux = vsubq_f32(fi, j);
// fmod
- c = vdivq_f32(aux, code_length_chips_reg_f);
+ reciprocal = vrecpeq_f32(code_length_chips_reg_f);
+ reciprocal = vmulq_f32(vrecpsq_f32(code_length_chips_reg_f, reciprocal), reciprocal);
+ reciprocal = vmulq_f32(vrecpsq_f32(code_length_chips_reg_f, reciprocal), reciprocal); // this refinement is required!
+ c = vmulq_f32(aux, reciprocal);
i = vcvtq_s32_f32(c);
cTrunc = vcvtq_f32_s32(i);
base = vmulq_f32(cTrunc, code_length_chips_reg_f);
aux = vsubq_f32(aux, base);
- sign = vcvtq_f32_u32((vshrq_n_u32(vreinterpretq_u32_f32(aux), 31)));
- PlusHalf = vaddq_f32(aux, half);
- Round = vsubq_f32(PlusHalf, sign);
- local_code_chip_index_reg = vcvtq_s32_f32(Round);
+ local_code_chip_index_reg = vcvtq_s32_f32(aux);
negatives = vreinterpretq_s32_u32(vcltq_s32(local_code_chip_index_reg, zeros));
aux_i = vandq_s32(code_length_chips_reg_i, negatives);
local_code_chip_index_reg = vaddq_s32(local_code_chip_index_reg, aux_i);
- vst1q_s32((int32_t*)local_code_chip_index, local_code_chip_index_reg);
+
+ vst1q_s32((int*)local_code_chip_index, local_code_chip_index_reg);
for(unsigned int k = 0; k < 4; ++k)
{
_result[current_correlator_tap][n * 4 + k] = local_code[local_code_chip_index[k]];
@@ -380,8 +564,9 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_neon(lv_16sc_t** resu
}
for(unsigned int n = neon_iters * 4; n < num_output_samples; n++)
{
+ __builtin_prefetch(&_result[current_correlator_tap][n], 1, 0);
// resample code for current tap
- local_code_chip_index_ = (int)floor(code_phase_step_chips * (float)n + shifts_chips[current_correlator_tap] - rem_code_phase_chips);
+ local_code_chip_index_ = (int32_t)floor(code_phase_step_chips * (float)n + shifts_chips[current_correlator_tap] - rem_code_phase_chips);
local_code_chip_index_ = local_code_chip_index_ % code_length_chips;
//Take into account that in multitap correlators, the shifts can be negative!
if (local_code_chip_index_ < 0) local_code_chip_index_ += code_length_chips;
@@ -390,6 +575,7 @@ static inline void volk_gnsssdr_16ic_xn_resampler2_16ic_xn_neon(lv_16sc_t** resu
}
}
+
#endif
diff --git a/src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/kernels/volk_gnsssdr/volk_gnsssdr_32fc_xn_resampler_32fc_xn.h b/src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/kernels/volk_gnsssdr/volk_gnsssdr_32fc_xn_resampler_32fc_xn.h
index 816eb81..2609696 100644
--- a/src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/kernels/volk_gnsssdr/volk_gnsssdr_32fc_xn_resampler_32fc_xn.h
+++ b/src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/kernels/volk_gnsssdr/volk_gnsssdr_32fc_xn_resampler_32fc_xn.h
@@ -335,7 +335,7 @@ static inline void volk_gnsssdr_32fc_xn_resampler_32fc_xn_neon(lv_32fc_t** resul
const float32x4_t code_length_chips_reg_f = vdupq_n_f32((float)code_length_chips);
const int32x4_t code_length_chips_reg_i = vdupq_n_s32((int32_t)code_length_chips);
int32x4_t local_code_chip_index_reg, aux_i, negatives, i;
- float32x4_t aux, aux2, shifts_chips_reg, fi, c, j, cTrunc, base, indexn;
+ float32x4_t aux, aux2, shifts_chips_reg, fi, c, j, cTrunc, base, indexn, reciprocal;
__VOLK_ATTR_ALIGNED(16) const float vec[4] = { 0.0f, 1.0f, 2.0f, 3.0f };
uint32x4_t igx;
for (int current_correlator_tap = 0; current_correlator_tap < num_out_vectors; current_correlator_tap++)
@@ -345,6 +345,8 @@ static inline void volk_gnsssdr_32fc_xn_resampler_32fc_xn_neon(lv_32fc_t** resul
indexn = vld1q_f32((float*)vec);
for(unsigned int n = 0; n < neon_iters; n++)
{
+ __builtin_prefetch(&_result[current_correlator_tap][4 * n + 3], 1, 0);
+ __builtin_prefetch(&local_code_chip_index[4]);
aux = vmulq_f32(code_phase_step_chips_reg, indexn);
aux = vaddq_f32(aux, aux2);
// floor
@@ -354,7 +356,10 @@ static inline void volk_gnsssdr_32fc_xn_resampler_32fc_xn_neon(lv_32fc_t** resul
j = vcvtq_f32_s32(vandq_s32(vreinterpretq_s32_u32(igx), ones));
aux = vsubq_f32(fi, j);
// fmod
- c = vdivq_f32(aux, code_length_chips_reg_f);
+ reciprocal = vrecpeq_f32(code_length_chips_reg_f);
+ reciprocal = vmulq_f32(vrecpsq_f32(code_length_chips_reg_f, reciprocal), reciprocal);
+ reciprocal = vmulq_f32(vrecpsq_f32(code_length_chips_reg_f, reciprocal), reciprocal); // this refinement is required!
+ c = vmulq_f32(aux, reciprocal);
i = vcvtq_s32_f32(c);
cTrunc = vcvtq_f32_s32(i);
base = vmulq_f32(cTrunc, code_length_chips_reg_f);
@@ -364,6 +369,7 @@ static inline void volk_gnsssdr_32fc_xn_resampler_32fc_xn_neon(lv_32fc_t** resul
negatives = vreinterpretq_s32_u32(vcltq_s32(local_code_chip_index_reg, zeros));
aux_i = vandq_s32(code_length_chips_reg_i, negatives);
local_code_chip_index_reg = vaddq_s32(local_code_chip_index_reg, aux_i);
+
vst1q_s32((int32_t*)local_code_chip_index, local_code_chip_index_reg);
for(unsigned int k = 0; k < 4; ++k)
@@ -374,6 +380,7 @@ static inline void volk_gnsssdr_32fc_xn_resampler_32fc_xn_neon(lv_32fc_t** resul
}
for(unsigned int n = neon_iters * 4; n < num_points; n++)
{
+ __builtin_prefetch(&_result[current_correlator_tap][n], 1, 0);
// resample code for current tap
local_code_chip_index_ = (int32_t)floor(code_phase_step_chips * (float)n + shifts_chips[current_correlator_tap] - rem_code_phase_chips);
local_code_chip_index_ = local_code_chip_index_ % code_length_chips;
--
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