Subversion Repositories DashDisplay

Rev

Go to most recent revision | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed

  1. /* ----------------------------------------------------------------------    
  2. * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
  3. *    
  4. * $Date:        19. March 2015
  5. * $Revision:    V.1.4.5
  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.  
  41. #include "arm_math.h"
  42. #include "arm_common_tables.h"
  43.  
  44. /**    
  45.  * @ingroup groupController    
  46.  */
  47.  
  48.  /**    
  49.  * @addtogroup SinCos    
  50.  * @{    
  51.  */
  52.  
  53. /**    
  54.  * @brief  Q31 sin_cos function.  
  55.  * @param[in]  theta    scaled input value in degrees    
  56.  * @param[out] *pSinVal points to the processed sine output.    
  57.  * @param[out] *pCosVal points to the processed cosine output.    
  58.  * @return none.  
  59.  *    
  60.  * The Q31 input value is in the range [-1 0.999999] and is mapped to a degree value in the range [-180 179].  
  61.  *    
  62.  */
  63.  
  64. void arm_sin_cos_q31(
  65.   q31_t theta,
  66.   q31_t * pSinVal,
  67.   q31_t * pCosVal)
  68. {
  69.   q31_t fract;                                 /* Temporary variables for input, output */
  70.   uint16_t indexS, indexC;                     /* Index variable */
  71.   q31_t f1, f2, d1, d2;                        /* Two nearest output values */
  72.   q31_t Dn, Df;
  73.   q63_t temp;
  74.  
  75.   /* Calculate the nearest index */
  76.   indexS = (uint32_t)theta >> CONTROLLER_Q31_SHIFT;
  77.   indexC = (indexS + 128) & 0x1ff;
  78.  
  79.   /* Calculation of fractional value */
  80.   fract = (theta - (indexS << CONTROLLER_Q31_SHIFT)) << 8;
  81.  
  82.   /* Read two nearest values of input value from the cos & sin tables */
  83.   f1 = sinTable_q31[indexC+0];
  84.   f2 = sinTable_q31[indexC+1];
  85.   d1 = -sinTable_q31[indexS+0];
  86.   d2 = -sinTable_q31[indexS+1];
  87.  
  88.   Dn = 0x1921FB5; // delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE
  89.   Df = f2 - f1; // delta between the values of the functions
  90.   temp = Dn*((q63_t)d1 + d2);
  91.   temp = temp - ((q63_t)Df << 32);
  92.   temp = (q63_t)fract*(temp >> 31);
  93.   temp = temp + ((3*(q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1))*Dn);
  94.   temp = (q63_t)fract*(temp >> 31);
  95.   temp = temp + (q63_t)d1*Dn;
  96.   temp = (q63_t)fract*(temp >> 31);
  97.  
  98.   /* Calculation of cosine value */
  99.   *pCosVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
  100.  
  101.   /* Read two nearest values of input value from the cos & sin tables */
  102.   f1 = sinTable_q31[indexS+0];
  103.   f2 = sinTable_q31[indexS+1];
  104.   d1 = sinTable_q31[indexC+0];
  105.   d2 = sinTable_q31[indexC+1];
  106.  
  107.   Df = f2 - f1; // delta between the values of the functions
  108.   temp = Dn*((q63_t)d1 + d2);
  109.   temp = temp - ((q63_t)Df << 32);
  110.   temp = (q63_t)fract*(temp >> 31);
  111.   temp = temp + ((3*(q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1))*Dn);
  112.   temp = (q63_t)fract*(temp >> 31);
  113.   temp = temp + (q63_t)d1*Dn;
  114.   temp = (q63_t)fract*(temp >> 31);
  115.  
  116.   /* Calculation of sine value */
  117.   *pSinVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
  118. }
  119.  
  120. /**    
  121.  * @} end of SinCos group    
  122.  */
  123.