summaryrefslogtreecommitdiff
path: root/Blink/Drivers/CMSIS/DSP/Source/ComplexMathFunctions/arm_cmplx_conj_f32.c
blob: 29e74bcdd197921ab29e2b9d6ab816dcdddb65e0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_cmplx_conj_f32.c
 * Description:  Floating-point complex conjugate
 *
 * $Date:        27. January 2017
 * $Revision:    V.1.5.1
 *
 * Target Processor: Cortex-M cores
 * -------------------------------------------------------------------- */
/*
 * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the License); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @defgroup cmplx_conj Complex Conjugate
 *
 * Conjugates the elements of a complex data vector.
 *
 * The <code>pSrc</code> points to the source data and
 * <code>pDst</code> points to the where the result should be written.
 * <code>numSamples</code> specifies the number of complex samples
 * and the data in each array is stored in an interleaved fashion
 * (real, imag, real, imag, ...).
 * Each array has a total of <code>2*numSamples</code> values.
 * The underlying algorithm is used:
 *
 * <pre>
 * for(n=0; n<numSamples; n++) {
 *     pDst[(2*n)+0)] = pSrc[(2*n)+0];     // real part
 *     pDst[(2*n)+1)] = -pSrc[(2*n)+1];    // imag part
 * }
 * </pre>
 *
 * There are separate functions for floating-point, Q15, and Q31 data types.
 */

/**
 * @addtogroup cmplx_conj
 * @{
 */

/**
 * @brief  Floating-point complex conjugate.
 * @param  *pSrc points to the input vector
 * @param  *pDst points to the output vector
 * @param  numSamples number of complex samples in each vector
 * @return none.
 */

void arm_cmplx_conj_f32(
  float32_t * pSrc,
  float32_t * pDst,
  uint32_t numSamples)
{
  uint32_t blkCnt;                               /* loop counter */

#if defined (ARM_MATH_DSP)

  /* Run the below code for Cortex-M4 and Cortex-M3 */
  float32_t inR1, inR2, inR3, inR4;
  float32_t inI1, inI2, inI3, inI4;

  /*loop Unrolling */
  blkCnt = numSamples >> 2U;

  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
   ** a second loop below computes the remaining 1 to 3 samples. */
  while (blkCnt > 0U)
  {
    /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
    /* Calculate Complex Conjugate and then store the results in the destination buffer. */
    /* read real input samples */
    inR1 = pSrc[0];
    /* store real samples to destination */
    pDst[0] = inR1;
    inR2 = pSrc[2];
    pDst[2] = inR2;
    inR3 = pSrc[4];
    pDst[4] = inR3;
    inR4 = pSrc[6];
    pDst[6] = inR4;

    /* read imaginary input samples */
    inI1 = pSrc[1];
    inI2 = pSrc[3];

    /* conjugate input */
    inI1 = -inI1;

    /* read imaginary input samples */
    inI3 = pSrc[5];

    /* conjugate input */
    inI2 = -inI2;

    /* read imaginary input samples */
    inI4 = pSrc[7];

    /* conjugate input */
    inI3 = -inI3;

    /* store imaginary samples to destination */
    pDst[1] = inI1;
    pDst[3] = inI2;

    /* conjugate input */
    inI4 = -inI4;

    /* store imaginary samples to destination */
    pDst[5] = inI3;

    /* increment source pointer by 8 to process next sampels */
    pSrc += 8U;

    /* store imaginary sample to destination */
    pDst[7] = inI4;

    /* increment destination pointer by 8 to store next samples */
    pDst += 8U;

    /* Decrement the loop counter */
    blkCnt--;
  }

  /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
   ** No loop unrolling is used. */
  blkCnt = numSamples % 0x4U;

#else

  /* Run the below code for Cortex-M0 */
  blkCnt = numSamples;

#endif /* #if defined (ARM_MATH_DSP) */

  while (blkCnt > 0U)
  {
    /* realOut + j (imagOut) = realIn + j (-1) imagIn */
    /* Calculate Complex Conjugate and then store the results in the destination buffer. */
    *pDst++ = *pSrc++;
    *pDst++ = -*pSrc++;

    /* Decrement the loop counter */
    blkCnt--;
  }
}

/**
 * @} end of cmplx_conj group
 */