CMSIS DSP Software Library: arm_cos_f32.c Source File Main Page Modules Data Structures Files Examples File List Globals arm_cos_f32.c Go to the documentation of this file.00001 /* ---------------------------------------------------------------------- 00002 * Copyright (C) 2010 ARM Limited. All rights reserved. 00003 * 00004 * $Date: 29. November 2010 00005 * $Revision: V1.0.3 00006 * 00007 * Project: CMSIS DSP Library 00008 * Title: arm_cos_f32.c 00009 * 00010 * Description: Fast cosine calculation for floating-point values. 00011 * 00012 * Target Processor: Cortex-M4/Cortex-M3 00013 * 00014 * Version 1.0.3 2010/11/29 00015 * Re-organized the CMSIS folders and updated documentation. 00016 * 00017 * Version 1.0.2 2010/11/11 00018 * Documentation updated. 00019 * 00020 * Version 1.0.1 2010/10/05 00021 * Production release and review comments incorporated. 00022 * 00023 * Version 1.0.0 2010/09/20 00024 * Production release and review comments incorporated. 00025 * -------------------------------------------------------------------- */ 00026 00027 #include "arm_math.h" 00083 static const float32_t cosTable[259] = { 00084 0.999698817729949950f, 1.000000000000000000f, 0.999698817729949950f, 00085 0.998795449733734130f, 0.997290432453155520f, 0.995184719562530520f, 00086 0.992479562759399410f, 0.989176511764526370f, 00087 0.985277652740478520f, 0.980785250663757320f, 0.975702106952667240f, 00088 0.970031261444091800f, 0.963776051998138430f, 0.956940352916717530f, 00089 0.949528157711029050f, 0.941544055938720700f, 00090 0.932992815971374510f, 0.923879504203796390f, 0.914209783077239990f, 00091 0.903989315032958980f, 0.893224298954010010f, 0.881921291351318360f, 00092 0.870086967945098880f, 0.857728600502014160f, 00093 0.844853579998016360f, 0.831469595432281490f, 0.817584812641143800f, 00094 0.803207516670227050f, 0.788346409797668460f, 0.773010432720184330f, 00095 0.757208824157714840f, 0.740951120853424070f, 00096 0.724247097969055180f, 0.707106769084930420f, 0.689540565013885500f, 00097 0.671558976173400880f, 0.653172850608825680f, 0.634393274784088130f, 00098 0.615231573581695560f, 0.595699310302734380f, 00099 0.575808167457580570f, 0.555570244789123540f, 0.534997642040252690f, 00100 0.514102756977081300f, 0.492898195981979370f, 0.471396744251251220f, 00101 0.449611335992813110f, 0.427555084228515630f, 00102 0.405241310596466060f, 0.382683426141738890f, 0.359895050525665280f, 00103 0.336889863014221190f, 0.313681751489639280f, 0.290284663438797000f, 00104 0.266712754964828490f, 0.242980182170867920f, 00105 0.219101235270500180f, 0.195090323686599730f, 0.170961886644363400f, 00106 0.146730467677116390f, 0.122410677373409270f, 0.098017141222953796f, 00107 0.073564566671848297f, 0.049067676067352295f, 00108 0.024541229009628296f, 0.000000000000000061f, -0.024541229009628296f, 00109 -0.049067676067352295f, -0.073564566671848297f, -0.098017141222953796f, 00110 -0.122410677373409270f, -0.146730467677116390f, 00111 -0.170961886644363400f, -0.195090323686599730f, -0.219101235270500180f, 00112 -0.242980182170867920f, -0.266712754964828490f, -0.290284663438797000f, 00113 -0.313681751489639280f, -0.336889863014221190f, 00114 -0.359895050525665280f, -0.382683426141738890f, -0.405241310596466060f, 00115 -0.427555084228515630f, -0.449611335992813110f, -0.471396744251251220f, 00116 -0.492898195981979370f, -0.514102756977081300f, 00117 -0.534997642040252690f, -0.555570244789123540f, -0.575808167457580570f, 00118 -0.595699310302734380f, -0.615231573581695560f, -0.634393274784088130f, 00119 -0.653172850608825680f, -0.671558976173400880f, 00120 -0.689540565013885500f, -0.707106769084930420f, -0.724247097969055180f, 00121 -0.740951120853424070f, -0.757208824157714840f, -0.773010432720184330f, 00122 -0.788346409797668460f, -0.803207516670227050f, 00123 -0.817584812641143800f, -0.831469595432281490f, -0.844853579998016360f, 00124 -0.857728600502014160f, -0.870086967945098880f, -0.881921291351318360f, 00125 -0.893224298954010010f, -0.903989315032958980f, 00126 -0.914209783077239990f, -0.923879504203796390f, -0.932992815971374510f, 00127 -0.941544055938720700f, -0.949528157711029050f, -0.956940352916717530f, 00128 -0.963776051998138430f, -0.970031261444091800f, 00129 -0.975702106952667240f, -0.980785250663757320f, -0.985277652740478520f, 00130 -0.989176511764526370f, -0.992479562759399410f, -0.995184719562530520f, 00131 -0.997290432453155520f, -0.998795449733734130f, 00132 -0.999698817729949950f, -1.000000000000000000f, -0.999698817729949950f, 00133 -0.998795449733734130f, -0.997290432453155520f, -0.995184719562530520f, 00134 -0.992479562759399410f, -0.989176511764526370f, 00135 -0.985277652740478520f, -0.980785250663757320f, -0.975702106952667240f, 00136 -0.970031261444091800f, -0.963776051998138430f, -0.956940352916717530f, 00137 -0.949528157711029050f, -0.941544055938720700f, 00138 -0.932992815971374510f, -0.923879504203796390f, -0.914209783077239990f, 00139 -0.903989315032958980f, -0.893224298954010010f, -0.881921291351318360f, 00140 -0.870086967945098880f, -0.857728600502014160f, 00141 -0.844853579998016360f, -0.831469595432281490f, -0.817584812641143800f, 00142 -0.803207516670227050f, -0.788346409797668460f, -0.773010432720184330f, 00143 -0.757208824157714840f, -0.740951120853424070f, 00144 -0.724247097969055180f, -0.707106769084930420f, -0.689540565013885500f, 00145 -0.671558976173400880f, -0.653172850608825680f, -0.634393274784088130f, 00146 -0.615231573581695560f, -0.595699310302734380f, 00147 -0.575808167457580570f, -0.555570244789123540f, -0.534997642040252690f, 00148 -0.514102756977081300f, -0.492898195981979370f, -0.471396744251251220f, 00149 -0.449611335992813110f, -0.427555084228515630f, 00150 -0.405241310596466060f, -0.382683426141738890f, -0.359895050525665280f, 00151 -0.336889863014221190f, -0.313681751489639280f, -0.290284663438797000f, 00152 -0.266712754964828490f, -0.242980182170867920f, 00153 -0.219101235270500180f, -0.195090323686599730f, -0.170961886644363400f, 00154 -0.146730467677116390f, -0.122410677373409270f, -0.098017141222953796f, 00155 -0.073564566671848297f, -0.049067676067352295f, 00156 -0.024541229009628296f, -0.000000000000000184f, 0.024541229009628296f, 00157 0.049067676067352295f, 0.073564566671848297f, 0.098017141222953796f, 00158 0.122410677373409270f, 0.146730467677116390f, 00159 0.170961886644363400f, 0.195090323686599730f, 0.219101235270500180f, 00160 0.242980182170867920f, 0.266712754964828490f, 0.290284663438797000f, 00161 0.313681751489639280f, 0.336889863014221190f, 00162 0.359895050525665280f, 0.382683426141738890f, 0.405241310596466060f, 00163 0.427555084228515630f, 0.449611335992813110f, 0.471396744251251220f, 00164 0.492898195981979370f, 0.514102756977081300f, 00165 0.534997642040252690f, 0.555570244789123540f, 0.575808167457580570f, 00166 0.595699310302734380f, 0.615231573581695560f, 0.634393274784088130f, 00167 0.653172850608825680f, 0.671558976173400880f, 00168 0.689540565013885500f, 0.707106769084930420f, 0.724247097969055180f, 00169 0.740951120853424070f, 0.757208824157714840f, 0.773010432720184330f, 00170 0.788346409797668460f, 0.803207516670227050f, 00171 0.817584812641143800f, 0.831469595432281490f, 0.844853579998016360f, 00172 0.857728600502014160f, 0.870086967945098880f, 0.881921291351318360f, 00173 0.893224298954010010f, 0.903989315032958980f, 00174 0.914209783077239990f, 0.923879504203796390f, 0.932992815971374510f, 00175 0.941544055938720700f, 0.949528157711029050f, 0.956940352916717530f, 00176 0.963776051998138430f, 0.970031261444091800f, 00177 0.975702106952667240f, 0.980785250663757320f, 0.985277652740478520f, 00178 0.989176511764526370f, 0.992479562759399410f, 0.995184719562530520f, 00179 0.997290432453155520f, 0.998795449733734130f, 00180 0.999698817729949950f, 1.000000000000000000f, 0.999698817729949950f 00181 }; 00182 00189 float32_t arm_cos_f32( 00190 float32_t x) 00191 { 00192 float32_t cosVal, fract, in; 00193 uint32_t index; 00194 uint32_t tableSize = (uint32_t) TABLE_SIZE; 00195 float32_t wa, wb, wc, wd; 00196 float32_t a, b, c, d; 00197 float32_t *tablePtr; 00198 int32_t n; 00199 00200 /* input x is in radians */ 00201 /* Scale the input to [0 1] range from [0 2*PI] , divide input by 2*pi */ 00202 in = x * 0.159154943092f; 00203 00204 /* Calculation of floor value of input */ 00205 n = (int32_t) in; 00206 00207 /* Make negative values towards -infinity */ 00208 if(x < 0.0f) 00209 { 00210 n = n - 1; 00211 } 00212 00213 /* Map input value to [0 1] */ 00214 in = in - (float32_t) n; 00215 00216 /* Calculation of index of the table */ 00217 index = (uint32_t) (tableSize * in); 00218 00219 /* fractional value calculation */ 00220 fract = ((float32_t) tableSize * in) - (float32_t) index; 00221 00222 /* Initialise table pointer */ 00223 tablePtr = (float32_t *) & cosTable[index]; 00224 00225 /* Read four nearest values of input value from the cos table */ 00226 a = *tablePtr++; 00227 b = *tablePtr++; 00228 c = *tablePtr++; 00229 d = *tablePtr++; 00230 00231 /* Cubic interpolation process */ 00232 wa = -(((0.166666667f) * fract) * (fract * fract)) + 00233 (((0.5f) * (fract * fract)) - ((0.3333333333333f) * fract)); 00234 wb = ((((0.5f) * fract) * (fract * fract)) - (fract * fract)) + 00235 (-((0.5f) * fract) + 1.0f); 00236 wc = -(((0.5f) * fract) * (fract * fract)) + 00237 (((0.5f) * (fract * fract)) + fract); 00238 wd = (((0.166666667f) * fract) * (fract * fract)) - 00239 ((0.166666667f) * fract); 00240 00241 /* Calculate cos value */ 00242 cosVal = ((a * wa) + (b * wb)) + ((c * wc) + (d * wd)); 00243 00244 /* Return the output value */ 00245 return (cosVal); 00246 00247 } 00248  All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Defines Generated on Mon Nov 29 2010 17:19:56 for CMSIS DSP Software Library by  1.7.2