/ Drivers / CMSIS / DSP / Source / ComplexMathFunctions / arm_cmplx_dot_prod_f16.c
arm_cmplx_dot_prod_f16.c
  1  /* ----------------------------------------------------------------------
  2   * Project:      CMSIS DSP Library
  3   * Title:        arm_cmplx_dot_prod_f16.c
  4   * Description:  Floating-point complex dot product
  5   *
  6   * $Date:        23 April 2021
  7   * $Revision:    V1.9.0
  8   *
  9   * Target Processor: Cortex-M and Cortex-A cores
 10   * -------------------------------------------------------------------- */
 11  /*
 12   * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
 13   *
 14   * SPDX-License-Identifier: Apache-2.0
 15   *
 16   * Licensed under the Apache License, Version 2.0 (the License); you may
 17   * not use this file except in compliance with the License.
 18   * You may obtain a copy of the License at
 19   *
 20   * www.apache.org/licenses/LICENSE-2.0
 21   *
 22   * Unless required by applicable law or agreed to in writing, software
 23   * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 24   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 25   * See the License for the specific language governing permissions and
 26   * limitations under the License.
 27   */
 28  
 29  #include "dsp/complex_math_functions_f16.h"
 30  
 31  #if defined(ARM_FLOAT16_SUPPORTED)
 32  
 33  
 34  /**
 35    @ingroup groupCmplxMath
 36   */
 37  
 38  /**
 39    @defgroup cmplx_dot_prod Complex Dot Product
 40  
 41    Computes the dot product of two complex vectors.
 42    The vectors are multiplied element-by-element and then summed.
 43  
 44    The <code>pSrcA</code> points to the first complex input vector and
 45    <code>pSrcB</code> points to the second complex input vector.
 46    <code>numSamples</code> specifies the number of complex samples
 47    and the data in each array is stored in an interleaved fashion
 48    (real, imag, real, imag, ...).
 49    Each array has a total of <code>2*numSamples</code> values.
 50  
 51    The underlying algorithm is used:
 52  
 53    <pre>
 54    realResult = 0;
 55    imagResult = 0;
 56    for (n = 0; n < numSamples; n++) {
 57        realResult += pSrcA[(2*n)+0] * pSrcB[(2*n)+0] - pSrcA[(2*n)+1] * pSrcB[(2*n)+1];
 58        imagResult += pSrcA[(2*n)+0] * pSrcB[(2*n)+1] + pSrcA[(2*n)+1] * pSrcB[(2*n)+0];
 59    }
 60    </pre>
 61  
 62    There are separate functions for floating-point, Q15, and Q31 data types.
 63   */
 64  
 65  /**
 66    @addtogroup cmplx_dot_prod
 67    @{
 68   */
 69  
 70  /**
 71    @brief         Floating-point complex dot product.
 72    @param[in]     pSrcA       points to the first input vector
 73    @param[in]     pSrcB       points to the second input vector
 74    @param[in]     numSamples  number of samples in each vector
 75    @param[out]    realResult  real part of the result returned here
 76    @param[out]    imagResult  imaginary part of the result returned here
 77    @return        none
 78   */
 79  
 80  #if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE)
 81  
 82  #include "arm_helium_utils.h"
 83  
 84  void arm_cmplx_dot_prod_f16(
 85      const float16_t * pSrcA,
 86      const float16_t * pSrcB,
 87      uint32_t numSamples,
 88      float16_t * realResult,
 89      float16_t * imagResult)
 90  {
 91      int32_t         blkCnt;
 92      float16_t       real_sum, imag_sum;
 93      f16x8_t         vecSrcA, vecSrcB;
 94      f16x8_t         vec_acc = vdupq_n_f16(0.0f16);
 95      f16x8_t         vecSrcC, vecSrcD;
 96  
 97      blkCnt = (numSamples >> 3);
 98      blkCnt -= 1;
 99      if (blkCnt > 0) {
100          /* should give more freedom to generate stall free code */
101          vecSrcA = vld1q( pSrcA);
102          vecSrcB = vld1q( pSrcB);
103          pSrcA += 8;
104          pSrcB += 8;
105  
106          while (blkCnt > 0) {
107              vec_acc = vcmlaq(vec_acc, vecSrcA, vecSrcB);
108              vecSrcC = vld1q(pSrcA);
109              pSrcA += 8;
110  
111              vec_acc = vcmlaq_rot90(vec_acc, vecSrcA, vecSrcB);
112              vecSrcD = vld1q(pSrcB);
113              pSrcB += 8;
114  
115              vec_acc = vcmlaq(vec_acc, vecSrcC, vecSrcD);
116              vecSrcA = vld1q(pSrcA);
117              pSrcA += 8;
118  
119              vec_acc = vcmlaq_rot90(vec_acc, vecSrcC, vecSrcD);
120              vecSrcB = vld1q(pSrcB);
121              pSrcB += 8;
122              /*
123               * Decrement the blockSize loop counter
124               */
125              blkCnt--;
126          }
127  
128          /* process last elements out of the loop avoid the armclang breaking the SW pipeline */
129          vec_acc = vcmlaq(vec_acc, vecSrcA, vecSrcB);
130          vecSrcC = vld1q(pSrcA);
131  
132          vec_acc = vcmlaq_rot90(vec_acc, vecSrcA, vecSrcB);
133          vecSrcD = vld1q(pSrcB);
134  
135          vec_acc = vcmlaq(vec_acc, vecSrcC, vecSrcD);
136          vec_acc = vcmlaq_rot90(vec_acc, vecSrcC, vecSrcD);
137  
138          /*
139           * tail
140           */
141          blkCnt = CMPLX_DIM * (numSamples & 7);
142          while (blkCnt > 0) {
143              mve_pred16_t    p = vctp16q(blkCnt);
144              pSrcA += 8;
145              pSrcB += 8;
146  
147              vecSrcA = vldrhq_z_f16(pSrcA, p);
148              vecSrcB = vldrhq_z_f16(pSrcB, p);
149              vec_acc = vcmlaq_m(vec_acc, vecSrcA, vecSrcB, p);
150              vec_acc = vcmlaq_rot90_m(vec_acc, vecSrcA, vecSrcB, p);
151  
152              blkCnt -= 8;
153          }
154      } else {
155          /* small vector */
156          blkCnt = numSamples * CMPLX_DIM;
157          vec_acc = vdupq_n_f16(0.0f16);
158  
159          do {
160              mve_pred16_t    p = vctp16q(blkCnt);
161  
162              vecSrcA = vldrhq_z_f16(pSrcA, p);
163              vecSrcB = vldrhq_z_f16(pSrcB, p);
164  
165              vec_acc = vcmlaq_m(vec_acc, vecSrcA, vecSrcB, p);
166              vec_acc = vcmlaq_rot90_m(vec_acc, vecSrcA, vecSrcB, p);
167  
168              /*
169               * Decrement the blkCnt loop counter
170               * Advance vector source and destination pointers
171               */
172              pSrcA += 8;
173              pSrcB += 8;
174              blkCnt -= 8;
175          }
176          while (blkCnt > 0);
177      }
178  
179      /* Sum the partial parts */
180      mve_cmplx_sum_intra_r_i_f16(vec_acc, real_sum, imag_sum);
181  
182      /*
183       * Store the real and imaginary results in the destination buffers
184       */
185      *realResult = real_sum;
186      *imagResult = imag_sum;
187  }
188  
189  #else
190  void arm_cmplx_dot_prod_f16(
191    const float16_t * pSrcA,
192    const float16_t * pSrcB,
193          uint32_t numSamples,
194          float16_t * realResult,
195          float16_t * imagResult)
196  {
197          uint32_t blkCnt;                               /* Loop counter */
198          _Float16 real_sum = 0.0f, imag_sum = 0.0f;    /* Temporary result variables */
199          _Float16 a0,b0,c0,d0;
200  
201  #if defined (ARM_MATH_LOOPUNROLL) && !defined(ARM_MATH_AUTOVECTORIZE)
202  
203    /* Loop unrolling: Compute 4 outputs at a time */
204    blkCnt = numSamples >> 2U;
205  
206    while (blkCnt > 0U)
207    {
208      a0 = *pSrcA++;
209      b0 = *pSrcA++;
210      c0 = *pSrcB++;
211      d0 = *pSrcB++;
212  
213      real_sum += a0 * c0;
214      imag_sum += a0 * d0;
215      real_sum -= b0 * d0;
216      imag_sum += b0 * c0;
217  
218      a0 = *pSrcA++;
219      b0 = *pSrcA++;
220      c0 = *pSrcB++;
221      d0 = *pSrcB++;
222  
223      real_sum += a0 * c0;
224      imag_sum += a0 * d0;
225      real_sum -= b0 * d0;
226      imag_sum += b0 * c0;
227  
228      a0 = *pSrcA++;
229      b0 = *pSrcA++;
230      c0 = *pSrcB++;
231      d0 = *pSrcB++;
232  
233      real_sum += a0 * c0;
234      imag_sum += a0 * d0;
235      real_sum -= b0 * d0;
236      imag_sum += b0 * c0;
237  
238      a0 = *pSrcA++;
239      b0 = *pSrcA++;
240      c0 = *pSrcB++;
241      d0 = *pSrcB++;
242  
243      real_sum += a0 * c0;
244      imag_sum += a0 * d0;
245      real_sum -= b0 * d0;
246      imag_sum += b0 * c0;
247  
248      /* Decrement loop counter */
249      blkCnt--;
250    }
251  
252    /* Loop unrolling: Compute remaining outputs */
253    blkCnt = numSamples % 0x4U;
254  
255  #else
256  
257    /* Initialize blkCnt with number of samples */
258    blkCnt = numSamples;
259  
260  #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
261  
262    while (blkCnt > 0U)
263    {
264      a0 = *pSrcA++;
265      b0 = *pSrcA++;
266      c0 = *pSrcB++;
267      d0 = *pSrcB++;
268  
269      real_sum += a0 * c0;
270      imag_sum += a0 * d0;
271      real_sum -= b0 * d0;
272      imag_sum += b0 * c0;
273  
274      /* Decrement loop counter */
275      blkCnt--;
276    }
277  
278    /* Store real and imaginary result in destination buffer. */
279    *realResult = real_sum;
280    *imagResult = imag_sum;
281  }
282  #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
283  
284  /**
285    @} end of cmplx_dot_prod group
286   */
287  
288  #endif /* #if defined(ARM_FLOAT16_SUPPORTED) */