Diff: cmsis_dsp/FastMathFunctions/arm_cos_f32.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FastMathFunctions/arm_cos_f32.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,280 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_cos_f32.c    
+*    
+* Description:    Fast cosine calculation for floating-point values.   
+*    
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*  
+* Version 1.1.0 2012/02/15 
+*    Updated with more optimizations, bug fixes and minor API changes.  
+*   
+* Version 1.0.10 2011/7/15  
+*    Big Endian support added and Merged M0 and M3/M4 Source code.   
+*    
+* Version 1.0.3 2010/11/29   
+*    Re-organized the CMSIS folders and updated documentation.    
+*     
+* Version 1.0.2 2010/11/11    
+*    Documentation updated.     
+*    
+* Version 1.0.1 2010/10/05     
+*    Production release and review comments incorporated.    
+*    
+* Version 1.0.0 2010/09/20     
+*    Production release and review comments incorporated.    
+* -------------------------------------------------------------------- */
+
+#include "arm_math.h"
+/**    
+ * @ingroup groupFastMath    
+ */
+
+/**    
+ * @defgroup cos Cosine    
+ *    
+ * Computes the trigonometric cosine function using a combination of table lookup   
+ * and cubic interpolation.  There are separate functions for   
+ * Q15, Q31, and floating-point data types.   
+ * The input to the floating-point version is in radians while the   
+ * fixed-point Q15 and Q31 have a scaled input with the range   
+ * [0 +0.9999] mapping to [0 2*pi), Where range excludes 2*pi.   
+ *   
+ * The implementation is based on table lookup using 256 values together with cubic interpolation.   
+ * The steps used are:   
+ *  -# Calculation of the nearest integer table index   
+ *  -# Fetch the four table values a, b, c, and d     
+ *  -# Compute the fractional portion (fract) of the table index.   
+ *  -# Calculation of wa, wb, wc, wd    
+ *  -# The final result equals <code>a*wa + b*wb + c*wc + d*wd</code>   
+ *   
+ * where   
+ * <pre>    
+ *    a=Table[index-1];    
+ *    b=Table[index+0];    
+ *    c=Table[index+1];    
+ *    d=Table[index+2];    
+ * </pre>   
+ * and   
+ * <pre>    
+ *    wa=-(1/6)*fract.^3 + (1/2)*fract.^2 - (1/3)*fract;    
+ *    wb=(1/2)*fract.^3 - fract.^2 - (1/2)*fract + 1;    
+ *    wc=-(1/2)*fract.^3+(1/2)*fract.^2+fract;    
+ *    wd=(1/6)*fract.^3 - (1/6)*fract;    
+ * </pre>    
+ */
+
+ /**    
+ * @addtogroup cos    
+ * @{    
+ */
+
+
+/**    
+* \par    
+* <b>Example code for Generation of Cos Table:</b>   
+* tableSize = 256;    
+* <pre>for(n = -1; n < (tableSize + 2); n++)    
+* {    
+*    cosTable[n+1]= cos(2*pi*n/tableSize);    
+* } </pre>    
+* where pi value is  3.14159265358979    
+*/
+
+static const float32_t cosTable[260] = {
+  0.999698817729949950f, 1.000000000000000000f, 0.999698817729949950f,
+  0.998795449733734130f, 0.997290432453155520f, 0.995184719562530520f,
+  0.992479562759399410f, 0.989176511764526370f,
+  0.985277652740478520f, 0.980785250663757320f, 0.975702106952667240f,
+  0.970031261444091800f, 0.963776051998138430f, 0.956940352916717530f,
+  0.949528157711029050f, 0.941544055938720700f,
+  0.932992815971374510f, 0.923879504203796390f, 0.914209783077239990f,
+  0.903989315032958980f, 0.893224298954010010f, 0.881921291351318360f,
+  0.870086967945098880f, 0.857728600502014160f,
+  0.844853579998016360f, 0.831469595432281490f, 0.817584812641143800f,
+  0.803207516670227050f, 0.788346409797668460f, 0.773010432720184330f,
+  0.757208824157714840f, 0.740951120853424070f,
+  0.724247097969055180f, 0.707106769084930420f, 0.689540565013885500f,
+  0.671558976173400880f, 0.653172850608825680f, 0.634393274784088130f,
+  0.615231573581695560f, 0.595699310302734380f,
+  0.575808167457580570f, 0.555570244789123540f, 0.534997642040252690f,
+  0.514102756977081300f, 0.492898195981979370f, 0.471396744251251220f,
+  0.449611335992813110f, 0.427555084228515630f,
+  0.405241310596466060f, 0.382683426141738890f, 0.359895050525665280f,
+  0.336889863014221190f, 0.313681751489639280f, 0.290284663438797000f,
+  0.266712754964828490f, 0.242980182170867920f,
+  0.219101235270500180f, 0.195090323686599730f, 0.170961886644363400f,
+  0.146730467677116390f, 0.122410677373409270f, 0.098017141222953796f,
+  0.073564566671848297f, 0.049067676067352295f,
+  0.024541229009628296f, 0.000000000000000061f, -0.024541229009628296f,
+  -0.049067676067352295f, -0.073564566671848297f, -0.098017141222953796f,
+  -0.122410677373409270f, -0.146730467677116390f,
+  -0.170961886644363400f, -0.195090323686599730f, -0.219101235270500180f,
+  -0.242980182170867920f, -0.266712754964828490f, -0.290284663438797000f,
+  -0.313681751489639280f, -0.336889863014221190f,
+  -0.359895050525665280f, -0.382683426141738890f, -0.405241310596466060f,
+  -0.427555084228515630f, -0.449611335992813110f, -0.471396744251251220f,
+  -0.492898195981979370f, -0.514102756977081300f,
+  -0.534997642040252690f, -0.555570244789123540f, -0.575808167457580570f,
+  -0.595699310302734380f, -0.615231573581695560f, -0.634393274784088130f,
+  -0.653172850608825680f, -0.671558976173400880f,
+  -0.689540565013885500f, -0.707106769084930420f, -0.724247097969055180f,
+  -0.740951120853424070f, -0.757208824157714840f, -0.773010432720184330f,
+  -0.788346409797668460f, -0.803207516670227050f,
+  -0.817584812641143800f, -0.831469595432281490f, -0.844853579998016360f,
+  -0.857728600502014160f, -0.870086967945098880f, -0.881921291351318360f,
+  -0.893224298954010010f, -0.903989315032958980f,
+  -0.914209783077239990f, -0.923879504203796390f, -0.932992815971374510f,
+  -0.941544055938720700f, -0.949528157711029050f, -0.956940352916717530f,
+  -0.963776051998138430f, -0.970031261444091800f,
+  -0.975702106952667240f, -0.980785250663757320f, -0.985277652740478520f,
+  -0.989176511764526370f, -0.992479562759399410f, -0.995184719562530520f,
+  -0.997290432453155520f, -0.998795449733734130f,
+  -0.999698817729949950f, -1.000000000000000000f, -0.999698817729949950f,
+  -0.998795449733734130f, -0.997290432453155520f, -0.995184719562530520f,
+  -0.992479562759399410f, -0.989176511764526370f,
+  -0.985277652740478520f, -0.980785250663757320f, -0.975702106952667240f,
+  -0.970031261444091800f, -0.963776051998138430f, -0.956940352916717530f,
+  -0.949528157711029050f, -0.941544055938720700f,
+  -0.932992815971374510f, -0.923879504203796390f, -0.914209783077239990f,
+  -0.903989315032958980f, -0.893224298954010010f, -0.881921291351318360f,
+  -0.870086967945098880f, -0.857728600502014160f,
+  -0.844853579998016360f, -0.831469595432281490f, -0.817584812641143800f,
+  -0.803207516670227050f, -0.788346409797668460f, -0.773010432720184330f,
+  -0.757208824157714840f, -0.740951120853424070f,
+  -0.724247097969055180f, -0.707106769084930420f, -0.689540565013885500f,
+  -0.671558976173400880f, -0.653172850608825680f, -0.634393274784088130f,
+  -0.615231573581695560f, -0.595699310302734380f,
+  -0.575808167457580570f, -0.555570244789123540f, -0.534997642040252690f,
+  -0.514102756977081300f, -0.492898195981979370f, -0.471396744251251220f,
+  -0.449611335992813110f, -0.427555084228515630f,
+  -0.405241310596466060f, -0.382683426141738890f, -0.359895050525665280f,
+  -0.336889863014221190f, -0.313681751489639280f, -0.290284663438797000f,
+  -0.266712754964828490f, -0.242980182170867920f,
+  -0.219101235270500180f, -0.195090323686599730f, -0.170961886644363400f,
+  -0.146730467677116390f, -0.122410677373409270f, -0.098017141222953796f,
+  -0.073564566671848297f, -0.049067676067352295f,
+  -0.024541229009628296f, -0.000000000000000184f, 0.024541229009628296f,
+  0.049067676067352295f, 0.073564566671848297f, 0.098017141222953796f,
+  0.122410677373409270f, 0.146730467677116390f,
+  0.170961886644363400f, 0.195090323686599730f, 0.219101235270500180f,
+  0.242980182170867920f, 0.266712754964828490f, 0.290284663438797000f,
+  0.313681751489639280f, 0.336889863014221190f,
+  0.359895050525665280f, 0.382683426141738890f, 0.405241310596466060f,
+  0.427555084228515630f, 0.449611335992813110f, 0.471396744251251220f,
+  0.492898195981979370f, 0.514102756977081300f,
+  0.534997642040252690f, 0.555570244789123540f, 0.575808167457580570f,
+  0.595699310302734380f, 0.615231573581695560f, 0.634393274784088130f,
+  0.653172850608825680f, 0.671558976173400880f,
+  0.689540565013885500f, 0.707106769084930420f, 0.724247097969055180f,
+  0.740951120853424070f, 0.757208824157714840f, 0.773010432720184330f,
+  0.788346409797668460f, 0.803207516670227050f,
+  0.817584812641143800f, 0.831469595432281490f, 0.844853579998016360f,
+  0.857728600502014160f, 0.870086967945098880f, 0.881921291351318360f,
+  0.893224298954010010f, 0.903989315032958980f,
+  0.914209783077239990f, 0.923879504203796390f, 0.932992815971374510f,
+  0.941544055938720700f, 0.949528157711029050f, 0.956940352916717530f,
+  0.963776051998138430f, 0.970031261444091800f,
+  0.975702106952667240f, 0.980785250663757320f, 0.985277652740478520f,
+  0.989176511764526370f, 0.992479562759399410f, 0.995184719562530520f,
+  0.997290432453155520f, 0.998795449733734130f,
+  0.999698817729949950f, 1.000000000000000000f, 0.999698817729949950f,
+  0.998795449733734130f
+};
+
+/**   
+ * @brief  Fast approximation to the trigonometric cosine function for floating-point data.   
+ * @param[in] x input value in radians.   
+ * @return cos(x).   
+ */
+
+
+float32_t arm_cos_f32(
+  float32_t x)
+{
+  float32_t cosVal, fract, in;
+  int32_t index;
+  uint32_t tableSize = (uint32_t) TABLE_SIZE;
+  float32_t wa, wb, wc, wd;
+  float32_t a, b, c, d;
+  float32_t *tablePtr;
+  int32_t n;
+  float32_t fractsq, fractby2, fractby6, fractby3, fractsqby2;
+  float32_t oneminusfractby2;
+  float32_t frby2xfrsq, frby6xfrsq;
+
+  /* input x is in radians */
+  /* Scale the input to [0 1] range from [0 2*PI] , divide input by 2*pi */
+  in = x * 0.159154943092f;
+
+  /* Calculation of floor value of input */
+  n = (int32_t) in;
+
+  /* Make negative values towards -infinity */
+  if(x < 0.0f)
+  {
+    n = n - 1;
+  }
+
+  /* Map input value to [0 1] */
+  in = in - (float32_t) n;
+
+  /* Calculation of index of the table */
+  index = (uint32_t) (tableSize * in);
+
+  /* fractional value calculation */
+  fract = ((float32_t) tableSize * in) - (float32_t) index;
+
+  /* Checking min and max index of table */
+  if(index < 0)
+  {
+    index = 0;
+  }
+  else if(index > 256)
+  {
+    index = 256;
+  }
+
+  /* Initialise table pointer */
+  tablePtr = (float32_t *) & cosTable[index];
+
+  /* Read four nearest values of input value from the cos table */
+  a = tablePtr[0];
+  b = tablePtr[1];
+  c = tablePtr[2];
+  d = tablePtr[3];
+
+  /* Cubic interpolation process */
+  fractsq = fract * fract;
+  fractby2 = fract * 0.5f;
+  fractby6 = fract * 0.166666667f;
+  fractby3 = fract * 0.3333333333333f;
+  fractsqby2 = fractsq * 0.5f;
+  frby2xfrsq = (fractby2) * fractsq;
+  frby6xfrsq = (fractby6) * fractsq;
+  oneminusfractby2 = 1.0f - fractby2;
+  wb = fractsqby2 - fractby3;
+  wc = (fractsqby2 + fract);
+  wa = wb - frby6xfrsq;
+  wb = frby2xfrsq - fractsq;
+  cosVal = wa * a;
+  wc = wc - frby2xfrsq;
+  wd = (frby6xfrsq) - fractby6;
+  wb = wb + oneminusfractby2;
+
+  /* Calculate cos value */
+  cosVal = (cosVal + (b * wb)) + ((c * wc) + (d * wd));
+
+  /* Return the output value */
+  return (cosVal);
+
+}
+
+/**    
+ * @} end of cos group    
+ */