lib/main/CMSIS/DSP/Source/ControllerFunctions/arm_sin_cos_q31.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_sin_cos_q31.c
   4  * Description:  Cosine & Sine calculation for Q31 values
   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 #include "arm_common_tables.h"
  31
  32 /**
  33  * @ingroup groupController
  34  */
  35
  36  /**
  37  * @addtogroup SinCos
  38  * @{
  39  */
  40
  41 /**
  42  * @brief  Q31 sin_cos function.
  43  * @param[in]  theta    scaled input value in degrees
  44  * @param[out] *pSinVal points to the processed sine output.
  45  * @param[out] *pCosVal points to the processed cosine output.
  46  * @return none.
  47  *
  48  * The Q31 input value is in the range [-1 0.999999] and is mapped to a degree value in the range [-180 179].
  49  *
  50  */
  51
  52 void arm_sin_cos_q31(
  53   q31_t theta,
  54   q31_t * pSinVal,
  55   q31_t * pCosVal)
  56 {
  57   q31_t fract;                                 /* Temporary variables for input, output */
  58   uint16_t indexS, indexC;                     /* Index variable */
  59   q31_t f1, f2, d1, d2;                        /* Two nearest output values */
  60   q31_t Dn, Df;
  61   q63_t temp;
  62
  63   /* Calculate the nearest index */
  64   indexS = (uint32_t)theta >> CONTROLLER_Q31_SHIFT;
  65   indexC = (indexS + 128) & 0x1ff;
  66
  67   /* Calculation of fractional value */
  68   fract = (theta - (indexS << CONTROLLER_Q31_SHIFT)) << 8;
  69
  70   /* Read two nearest values of input value from the cos & sin tables */
  71   f1 = sinTable_q31[indexC+0];
  72   f2 = sinTable_q31[indexC+1];
  73   d1 = -sinTable_q31[indexS+0];
  74   d2 = -sinTable_q31[indexS+1];
  75
  76   Dn = 0x1921FB5; // delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE
  77   Df = f2 - f1; // delta between the values of the functions
  78   temp = Dn*((q63_t)d1 + d2);
  79   temp = temp - ((q63_t)Df << 32);
  80   temp = (q63_t)fract*(temp >> 31);
  81   temp = temp + ((3*(q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1))*Dn);
  82   temp = (q63_t)fract*(temp >> 31);
  83   temp = temp + (q63_t)d1*Dn;
  84   temp = (q63_t)fract*(temp >> 31);
  85
  86   /* Calculation of cosine value */
  87   *pCosVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
  88
  89   /* Read two nearest values of input value from the cos & sin tables */
  90   f1 = sinTable_q31[indexS+0];
  91   f2 = sinTable_q31[indexS+1];
  92   d1 = sinTable_q31[indexC+0];
  93   d2 = sinTable_q31[indexC+1];
  94
  95   Df = f2 - f1; // delta between the values of the functions
  96   temp = Dn*((q63_t)d1 + d2);
  97   temp = temp - ((q63_t)Df << 32);
  98   temp = (q63_t)fract*(temp >> 31);
  99   temp = temp + ((3*(q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1))*Dn);
 100   temp = (q63_t)fract*(temp >> 31);
 101   temp = temp + (q63_t)d1*Dn;
 102   temp = (q63_t)fract*(temp >> 31);
 103
 104   /* Calculation of sine value */
 105   *pSinVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
 106 }
 107
 108 /**
 109  * @} end of SinCos group
 110  */