arm_sin_cos_q31.c 4.5 KB

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  1. /* ----------------------------------------------------------------------
  2. * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
  3. *
  4. * $Date: 12. March 2014
  5. * $Revision: V1.4.4
  6. *
  7. * Project: CMSIS DSP Library
  8. * Title: arm_sin_cos_q31.c
  9. *
  10. * Description: Cosine & Sine calculation for Q31 values.
  11. *
  12. * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13. *
  14. * Redistribution and use in source and binary forms, with or without
  15. * modification, are permitted provided that the following conditions
  16. * are met:
  17. * - Redistributions of source code must retain the above copyright
  18. * notice, this list of conditions and the following disclaimer.
  19. * - Redistributions in binary form must reproduce the above copyright
  20. * notice, this list of conditions and the following disclaimer in
  21. * the documentation and/or other materials provided with the
  22. * distribution.
  23. * - Neither the name of ARM LIMITED nor the names of its contributors
  24. * may be used to endorse or promote products derived from this
  25. * software without specific prior written permission.
  26. *
  27. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28. * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30. * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31. * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32. * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33. * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34. * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35. * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37. * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38. * POSSIBILITY OF SUCH DAMAGE.
  39. * -------------------------------------------------------------------- */
  40. #include "arm_math.h"
  41. #include "arm_common_tables.h"
  42. /**
  43. * @ingroup groupController
  44. */
  45. /**
  46. * @addtogroup SinCos
  47. * @{
  48. */
  49. /**
  50. * @brief Q31 sin_cos function.
  51. * @param[in] theta scaled input value in degrees
  52. * @param[out] *pSinVal points to the processed sine output.
  53. * @param[out] *pCosVal points to the processed cosine output.
  54. * @return none.
  55. *
  56. * The Q31 input value is in the range [-1 0.999999] and is mapped to a degree value in the range [-180 179].
  57. *
  58. */
  59. void arm_sin_cos_q31(
  60. q31_t theta,
  61. q31_t * pSinVal,
  62. q31_t * pCosVal)
  63. {
  64. q31_t fract; /* Temporary variables for input, output */
  65. uint16_t indexS, indexC; /* Index variable */
  66. q31_t f1, f2, d1, d2; /* Two nearest output values */
  67. q31_t Dn, Df;
  68. q63_t temp;
  69. /* Calculate the nearest index */
  70. indexS = (uint32_t)theta >> CONTROLLER_Q31_SHIFT;
  71. indexC = (indexS + 128) & 0x1ff;
  72. /* Calculation of fractional value */
  73. fract = (theta - (indexS << CONTROLLER_Q31_SHIFT)) << 8;
  74. /* Read two nearest values of input value from the cos & sin tables */
  75. f1 = sinTable_q31[indexC+0];
  76. f2 = sinTable_q31[indexC+1];
  77. d1 = -sinTable_q31[indexS+0];
  78. d2 = -sinTable_q31[indexS+1];
  79. Dn = 0x1921FB5; // delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE
  80. Df = f2 - f1; // delta between the values of the functions
  81. temp = Dn*((q63_t)d1 + d2);
  82. temp = temp - ((q63_t)Df << 32);
  83. temp = (q63_t)fract*(temp >> 31);
  84. temp = temp + ((3*(q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1))*Dn);
  85. temp = (q63_t)fract*(temp >> 31);
  86. temp = temp + (q63_t)d1*Dn;
  87. temp = (q63_t)fract*(temp >> 31);
  88. /* Calculation of cosine value */
  89. *pCosVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
  90. /* Read two nearest values of input value from the cos & sin tables */
  91. f1 = sinTable_q31[indexS+0];
  92. f2 = sinTable_q31[indexS+1];
  93. d1 = sinTable_q31[indexC+0];
  94. d2 = sinTable_q31[indexC+1];
  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. /* Calculation of sine value */
  104. *pSinVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
  105. }
  106. /**
  107. * @} end of SinCos group
  108. */