lib/main/CMSIS/DSP/Source/ComplexMathFunctions/arm_cmplx_conj_q15.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_cmplx_conj_q15.c
   4  * Description:  Q15 complex conjugate
   5  *
   6  * $Date:        27. January 2017
   7  * $Revision:    V.1.5.1
   8  *
   9  * Target Processor: Cortex-M cores
  10  * -------------------------------------------------------------------- */
  11 /*
  12  * Copyright (C) 2010-2017 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 "arm_math.h"
  30
  31 /**
  32  * @ingroup groupCmplxMath
  33  */
  34
  35 /**
  36  * @addtogroup cmplx_conj
  37  * @{
  38  */
  39
  40 /**
  41  * @brief  Q15 complex conjugate.
  42  * @param  *pSrc points to the input vector
  43  * @param  *pDst points to the output vector
  44  * @param  numSamples number of complex samples in each vector
  45  * @return none.
  46  *
  47  * <b>Scaling and Overflow Behavior:</b>
  48  * \par
  49  * The function uses saturating arithmetic.
  50  * The Q15 value -1 (0x8000) will be saturated to the maximum allowable positive value 0x7FFF.
  51  */
  52
  53 void arm_cmplx_conj_q15(
  54   q15_t * pSrc,
  55   q15_t * pDst,
  56   uint32_t numSamples)
  57 {
  58
  59 #if defined (ARM_MATH_DSP)
  60
  61   /* Run the below code for Cortex-M4 and Cortex-M3 */
  62   uint32_t blkCnt;                               /* loop counter */
  63   q31_t in1, in2, in3, in4;
  64   q31_t zero = 0;
  65
  66   /*loop Unrolling */
  67   blkCnt = numSamples >> 2U;
  68
  69   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  70    ** a second loop below computes the remaining 1 to 3 samples. */
  71   while (blkCnt > 0U)
  72   {
  73     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
  74     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
  75     in1 = *__SIMD32(pSrc)++;
  76     in2 = *__SIMD32(pSrc)++;
  77     in3 = *__SIMD32(pSrc)++;
  78     in4 = *__SIMD32(pSrc)++;
  79
  80 #ifndef ARM_MATH_BIG_ENDIAN
  81
  82     in1 = __QASX(zero, in1);
  83     in2 = __QASX(zero, in2);
  84     in3 = __QASX(zero, in3);
  85     in4 = __QASX(zero, in4);
  86
  87 #else
  88
  89     in1 = __QSAX(zero, in1);
  90     in2 = __QSAX(zero, in2);
  91     in3 = __QSAX(zero, in3);
  92     in4 = __QSAX(zero, in4);
  93
  94 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */
  95
  96     in1 = ((uint32_t) in1 >> 16) | ((uint32_t) in1 << 16);
  97     in2 = ((uint32_t) in2 >> 16) | ((uint32_t) in2 << 16);
  98     in3 = ((uint32_t) in3 >> 16) | ((uint32_t) in3 << 16);
  99     in4 = ((uint32_t) in4 >> 16) | ((uint32_t) in4 << 16);
 100
 101     *__SIMD32(pDst)++ = in1;
 102     *__SIMD32(pDst)++ = in2;
 103     *__SIMD32(pDst)++ = in3;
 104     *__SIMD32(pDst)++ = in4;
 105
 106     /* Decrement the loop counter */
 107     blkCnt--;
 108   }
 109
 110   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
 111    ** No loop unrolling is used. */
 112   blkCnt = numSamples % 0x4U;
 113
 114   while (blkCnt > 0U)
 115   {
 116     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
 117     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
 118     *pDst++ = *pSrc++;
 119     *pDst++ = __SSAT(-*pSrc++, 16);
 120
 121     /* Decrement the loop counter */
 122     blkCnt--;
 123   }
 124
 125 #else
 126
 127   q15_t in;
 128
 129   /* Run the below code for Cortex-M0 */
 130
 131   while (numSamples > 0U)
 132   {
 133     /* realOut + j (imagOut) = realIn+ j (-1) imagIn */
 134     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
 135     *pDst++ = *pSrc++;
 136     in = *pSrc++;
 137     *pDst++ = (in == (q15_t) 0x8000) ? 0x7fff : -in;
 138
 139     /* Decrement the loop counter */
 140     numSamples--;
 141   }
 142
 143 #endif /* #if defined (ARM_MATH_DSP) */
 144
 145 }
 146
 147 /**
 148  * @} end of cmplx_conj group
 149  */