arm_sin_q15.c
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00001 /* ---------------------------------------------------------------------- 00002 * Copyright (C) 2010 ARM Limited. All rights reserved. 00003 * 00004 * $Date: 15. July 2011 00005 * $Revision: V1.0.10 00006 * 00007 * Project: CMSIS DSP Library 00008 * Title: arm_sin_q15.c 00009 * 00010 * Description: Fast sine calculation for Q15 values. 00011 * 00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 00013 * 00014 * Version 1.0.10 2011/7/15 00015 * Big Endian support added and Merged M0 and M3/M4 Source code. 00016 * 00017 * Version 1.0.3 2010/11/29 00018 * Re-organized the CMSIS folders and updated documentation. 00019 * 00020 * Version 1.0.2 2010/11/11 00021 * Documentation updated. 00022 * 00023 * Version 1.0.1 2010/10/05 00024 * Production release and review comments incorporated. 00025 * 00026 * Version 1.0.0 2010/09/20 00027 * Production release and review comments incorporated. 00028 * -------------------------------------------------------------------- */ 00029 00030 #include "arm_math.h" 00031 00061 static const q15_t sinTableQ15[259] = { 00062 0xfcdc, 0x0, 0x324, 0x648, 0x96b, 0xc8c, 0xfab, 0x12c8, 00063 0x15e2, 0x18f9, 0x1c0c, 0x1f1a, 0x2224, 0x2528, 0x2827, 0x2b1f, 00064 0x2e11, 0x30fc, 0x33df, 0x36ba, 0x398d, 0x3c57, 0x3f17, 0x41ce, 00065 0x447b, 0x471d, 0x49b4, 0x4c40, 0x4ec0, 0x5134, 0x539b, 0x55f6, 00066 0x5843, 0x5a82, 0x5cb4, 0x5ed7, 0x60ec, 0x62f2, 0x64e9, 0x66d0, 00067 0x68a7, 0x6a6e, 0x6c24, 0x6dca, 0x6f5f, 0x70e3, 0x7255, 0x73b6, 00068 0x7505, 0x7642, 0x776c, 0x7885, 0x798a, 0x7a7d, 0x7b5d, 0x7c2a, 00069 0x7ce4, 0x7d8a, 0x7e1e, 0x7e9d, 0x7f0a, 0x7f62, 0x7fa7, 0x7fd9, 00070 0x7ff6, 0x7fff, 0x7ff6, 0x7fd9, 0x7fa7, 0x7f62, 0x7f0a, 0x7e9d, 00071 0x7e1e, 0x7d8a, 0x7ce4, 0x7c2a, 0x7b5d, 0x7a7d, 0x798a, 0x7885, 00072 0x776c, 0x7642, 0x7505, 0x73b6, 0x7255, 0x70e3, 0x6f5f, 0x6dca, 00073 0x6c24, 0x6a6e, 0x68a7, 0x66d0, 0x64e9, 0x62f2, 0x60ec, 0x5ed7, 00074 0x5cb4, 0x5a82, 0x5843, 0x55f6, 0x539b, 0x5134, 0x4ec0, 0x4c40, 00075 0x49b4, 0x471d, 0x447b, 0x41ce, 0x3f17, 0x3c57, 0x398d, 0x36ba, 00076 0x33df, 0x30fc, 0x2e11, 0x2b1f, 0x2827, 0x2528, 0x2224, 0x1f1a, 00077 0x1c0c, 0x18f9, 0x15e2, 0x12c8, 0xfab, 0xc8c, 0x96b, 0x648, 00078 0x324, 0x0, 0xfcdc, 0xf9b8, 0xf695, 0xf374, 0xf055, 0xed38, 00079 0xea1e, 0xe707, 0xe3f4, 0xe0e6, 0xdddc, 0xdad8, 0xd7d9, 0xd4e1, 00080 0xd1ef, 0xcf04, 0xcc21, 0xc946, 0xc673, 0xc3a9, 0xc0e9, 0xbe32, 00081 0xbb85, 0xb8e3, 0xb64c, 0xb3c0, 0xb140, 0xaecc, 0xac65, 0xaa0a, 00082 0xa7bd, 0xa57e, 0xa34c, 0xa129, 0x9f14, 0x9d0e, 0x9b17, 0x9930, 00083 0x9759, 0x9592, 0x93dc, 0x9236, 0x90a1, 0x8f1d, 0x8dab, 0x8c4a, 00084 0x8afb, 0x89be, 0x8894, 0x877b, 0x8676, 0x8583, 0x84a3, 0x83d6, 00085 0x831c, 0x8276, 0x81e2, 0x8163, 0x80f6, 0x809e, 0x8059, 0x8027, 00086 0x800a, 0x8000, 0x800a, 0x8027, 0x8059, 0x809e, 0x80f6, 0x8163, 00087 0x81e2, 0x8276, 0x831c, 0x83d6, 0x84a3, 0x8583, 0x8676, 0x877b, 00088 0x8894, 0x89be, 0x8afb, 0x8c4a, 0x8dab, 0x8f1d, 0x90a1, 0x9236, 00089 0x93dc, 0x9592, 0x9759, 0x9930, 0x9b17, 0x9d0e, 0x9f14, 0xa129, 00090 0xa34c, 0xa57e, 0xa7bd, 0xaa0a, 0xac65, 0xaecc, 0xb140, 0xb3c0, 00091 0xb64c, 0xb8e3, 0xbb85, 0xbe32, 0xc0e9, 0xc3a9, 0xc673, 0xc946, 00092 0xcc21, 0xcf04, 0xd1ef, 0xd4e1, 0xd7d9, 0xdad8, 0xdddc, 0xe0e6, 00093 0xe3f4, 0xe707, 0xea1e, 0xed38, 0xf055, 0xf374, 0xf695, 0xf9b8, 00094 0xfcdc, 0x0, 0x324 00095 }; 00096 00097 00106 q15_t arm_sin_q15( 00107 q15_t x) 00108 { 00109 q31_t sinVal; /* Temporary variables output */ 00110 q15_t *tablePtr; /* Pointer to table */ 00111 q15_t fract, in, in2; /* Temporary variables for input, output */ 00112 q31_t wa, wb, wc, wd; /* Cubic interpolation coefficients */ 00113 q15_t a, b, c, d; /* Four nearest output values */ 00114 q15_t fractCube, fractSquare; /* Temporary values for fractional value */ 00115 q15_t oneBy6 = 0x1555; /* Fixed point value of 1/6 */ 00116 q15_t tableSpacing = TABLE_SPACING_Q15; /* Table spacing */ 00117 int32_t index; /* Index variable */ 00118 00119 in = x; 00120 00121 /* Calculate the nearest index */ 00122 index = (int32_t) in / tableSpacing; 00123 00124 /* Calculate the nearest value of input */ 00125 in2 = (q15_t) ((index) * tableSpacing); 00126 00127 /* Calculation of fractional value */ 00128 fract = (in - in2) << 8; 00129 00130 /* fractSquare = fract * fract */ 00131 fractSquare = (q15_t) ((fract * fract) >> 15); 00132 00133 /* fractCube = fract * fract * fract */ 00134 fractCube = (q15_t) ((fractSquare * fract) >> 15); 00135 00136 /* Initialise table pointer */ 00137 tablePtr = (q15_t *) & sinTableQ15[index]; 00138 00139 /* Cubic interpolation process */ 00140 /* Calculation of wa */ 00141 /* wa = -(oneBy6)*fractCube + (fractSquare >> 1u) - (0x2AAA)*fract; */ 00142 wa = (q31_t) oneBy6 *fractCube; 00143 wa += (q31_t) 0x2AAA *fract; 00144 wa = -(wa >> 15); 00145 wa += ((q31_t) fractSquare >> 1u); 00146 00147 /* Read first nearest value of output from the sin table */ 00148 a = *tablePtr++; 00149 00150 /* sinVal = a * wa */ 00151 sinVal = a * wa; 00152 00153 /* Calculation of wb */ 00154 wb = (((q31_t) fractCube >> 1u) - (q31_t) fractSquare) - 00155 (((q31_t) fract >> 1u) - 0x7FFF); 00156 00157 /* Read second nearest value of output from the sin table */ 00158 b = *tablePtr++; 00159 00160 /* sinVal += b*wb */ 00161 sinVal += b * wb; 00162 00163 00164 /* Calculation of wc */ 00165 wc = -(q31_t) fractCube + fractSquare; 00166 wc = (wc >> 1u) + fract; 00167 00168 /* Read third nearest value of output from the sin table */ 00169 c = *tablePtr++; 00170 00171 /* sinVal += c*wc */ 00172 sinVal += c * wc; 00173 00174 /* Calculation of wd */ 00175 /* wd = (oneBy6)*fractCube - (oneBy6)*fract; */ 00176 fractCube = fractCube - fract; 00177 wd = ((q15_t) (((q31_t) oneBy6 * fractCube) >> 15)); 00178 00179 /* Read fourth nearest value of output from the sin table */ 00180 d = *tablePtr++; 00181 00182 /* sinVal += d*wd; */ 00183 sinVal += d * wd; 00184 00185 /* Return the output value in 1.15(q15) format */ 00186 return ((q15_t) (sinVal >> 15u)); 00187 00188 } 00189
