arm_sin_q15.c
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00001 /* ---------------------------------------------------------------------- 00002 * Copyright (C) 2011 ARM Limited. All rights reserved. 00003 * 00004 * $Date: 15. December 2011 00005 * $Revision: V2.0.0 00006 * 00007 * Project: Cortex-R DSP Library 00008 * Title: arm_sin_q15.c 00009 * 00010 * Description: Fast sine calculation for Q15 values. 00011 * 00012 * Target Processor: Cortex-R4/R5 00013 * 00014 * Version 1.0.0 2011/03/08 00015 * Alpha release. 00016 * 00017 * Version 1.0.1 2011/09/30 00018 * Beta release. 00019 * 00020 * Version 2.0.0 2011/12/15 00021 * Final release. 00022 * 00023 * -------------------------------------------------------------------- */ 00024 #include "arm_math.h" 00025 00055 static const q15_t sinTableQ15[259] = { 00056 0xfcdc, 0x0, 0x324, 0x648, 0x96b, 0xc8c, 0xfab, 0x12c8, 00057 0x15e2, 0x18f9, 0x1c0c, 0x1f1a, 0x2224, 0x2528, 0x2827, 0x2b1f, 00058 0x2e11, 0x30fc, 0x33df, 0x36ba, 0x398d, 0x3c57, 0x3f17, 0x41ce, 00059 0x447b, 0x471d, 0x49b4, 0x4c40, 0x4ec0, 0x5134, 0x539b, 0x55f6, 00060 0x5843, 0x5a82, 0x5cb4, 0x5ed7, 0x60ec, 0x62f2, 0x64e9, 0x66d0, 00061 0x68a7, 0x6a6e, 0x6c24, 0x6dca, 0x6f5f, 0x70e3, 0x7255, 0x73b6, 00062 0x7505, 0x7642, 0x776c, 0x7885, 0x798a, 0x7a7d, 0x7b5d, 0x7c2a, 00063 0x7ce4, 0x7d8a, 0x7e1e, 0x7e9d, 0x7f0a, 0x7f62, 0x7fa7, 0x7fd9, 00064 0x7ff6, 0x7fff, 0x7ff6, 0x7fd9, 0x7fa7, 0x7f62, 0x7f0a, 0x7e9d, 00065 0x7e1e, 0x7d8a, 0x7ce4, 0x7c2a, 0x7b5d, 0x7a7d, 0x798a, 0x7885, 00066 0x776c, 0x7642, 0x7505, 0x73b6, 0x7255, 0x70e3, 0x6f5f, 0x6dca, 00067 0x6c24, 0x6a6e, 0x68a7, 0x66d0, 0x64e9, 0x62f2, 0x60ec, 0x5ed7, 00068 0x5cb4, 0x5a82, 0x5843, 0x55f6, 0x539b, 0x5134, 0x4ec0, 0x4c40, 00069 0x49b4, 0x471d, 0x447b, 0x41ce, 0x3f17, 0x3c57, 0x398d, 0x36ba, 00070 0x33df, 0x30fc, 0x2e11, 0x2b1f, 0x2827, 0x2528, 0x2224, 0x1f1a, 00071 0x1c0c, 0x18f9, 0x15e2, 0x12c8, 0xfab, 0xc8c, 0x96b, 0x648, 00072 0x324, 0x0, 0xfcdc, 0xf9b8, 0xf695, 0xf374, 0xf055, 0xed38, 00073 0xea1e, 0xe707, 0xe3f4, 0xe0e6, 0xdddc, 0xdad8, 0xd7d9, 0xd4e1, 00074 0xd1ef, 0xcf04, 0xcc21, 0xc946, 0xc673, 0xc3a9, 0xc0e9, 0xbe32, 00075 0xbb85, 0xb8e3, 0xb64c, 0xb3c0, 0xb140, 0xaecc, 0xac65, 0xaa0a, 00076 0xa7bd, 0xa57e, 0xa34c, 0xa129, 0x9f14, 0x9d0e, 0x9b17, 0x9930, 00077 0x9759, 0x9592, 0x93dc, 0x9236, 0x90a1, 0x8f1d, 0x8dab, 0x8c4a, 00078 0x8afb, 0x89be, 0x8894, 0x877b, 0x8676, 0x8583, 0x84a3, 0x83d6, 00079 0x831c, 0x8276, 0x81e2, 0x8163, 0x80f6, 0x809e, 0x8059, 0x8027, 00080 0x800a, 0x8000, 0x800a, 0x8027, 0x8059, 0x809e, 0x80f6, 0x8163, 00081 0x81e2, 0x8276, 0x831c, 0x83d6, 0x84a3, 0x8583, 0x8676, 0x877b, 00082 0x8894, 0x89be, 0x8afb, 0x8c4a, 0x8dab, 0x8f1d, 0x90a1, 0x9236, 00083 0x93dc, 0x9592, 0x9759, 0x9930, 0x9b17, 0x9d0e, 0x9f14, 0xa129, 00084 0xa34c, 0xa57e, 0xa7bd, 0xaa0a, 0xac65, 0xaecc, 0xb140, 0xb3c0, 00085 0xb64c, 0xb8e3, 0xbb85, 0xbe32, 0xc0e9, 0xc3a9, 0xc673, 0xc946, 00086 0xcc21, 0xcf04, 0xd1ef, 0xd4e1, 0xd7d9, 0xdad8, 0xdddc, 0xe0e6, 00087 0xe3f4, 0xe707, 0xea1e, 0xed38, 0xf055, 0xf374, 0xf695, 0xf9b8, 00088 0xfcdc, 0x0, 0x324 00089 }; 00090 00091 00100 q15_t arm_sin_q15( 00101 q15_t x) 00102 { 00103 q31_t sinVal; /* Temporary variables output */ 00104 q15_t *tablePtr; /* Pointer to table */ 00105 q15_t fract, in, in2; /* Temporary variables for input, output */ 00106 q31_t wa, wb, wc, wd; /* Cubic interpolation coefficients */ 00107 q15_t a, b, c, d; /* Four nearest output values */ 00108 q15_t fractCube, fractSquare; /* Temporary values for fractional value */ 00109 q15_t oneBy6 = 0x1555; /* Fixed point value of 1/6 */ 00110 q15_t tableSpacing = TABLE_SPACING_Q15; /* Table spacing */ 00111 int32_t index; /* Index variable */ 00112 00113 in = x; 00114 00115 /* Calculate the nearest index */ 00116 index = (uint32_t) in / (uint32_t)tableSpacing; 00117 00118 /* Calculate the nearest value of input */ 00119 in2 = (q15_t) ((index) * tableSpacing); 00120 00121 /* Calculation of fractional value */ 00122 fract = (in - in2) << 8; 00123 00124 /* fractSquare = fract * fract */ 00125 fractSquare = (q15_t) ((fract * fract) >> 15); 00126 00127 /* fractCube = fract * fract * fract */ 00128 fractCube = (q15_t) ((fractSquare * fract) >> 15); 00129 00130 /* Initialise table pointer */ 00131 tablePtr = (q15_t *) & sinTableQ15[index]; 00132 00133 /* Cubic interpolation process */ 00134 /* Calculation of wa */ 00135 /* wa = -(oneBy6)*fractCube + (fractSquare >> 1u) - (0x2AAA)*fract; */ 00136 wa = (q31_t) oneBy6 *fractCube; 00137 wa += (q31_t) 0x2AAA * fract; 00138 00139 /* Calculation of wb */ 00140 wb = (((q31_t) fractCube >> 1u) - (q31_t) fractSquare) - 00141 (((q31_t) fract >> 1u) - 0x7FFF); 00142 00143 wa = -(wa >> 15); 00144 wa += ((q31_t) fractSquare >> 1u); 00145 00146 /* Read first nearest value of output from the sin table */ 00147 a = tablePtr[0]; 00148 00149 /* sinVal = a * wa */ 00150 sinVal = a * wa; 00151 00152 /* Read second nearest value of output from the sin table */ 00153 b = tablePtr[1]; 00154 00155 /* sinVal += b*wb */ 00156 sinVal += b * wb; 00157 00158 /* Calculation of wc */ 00159 wc = -(q31_t) fractCube + fractSquare; 00160 wc = (wc >> 1u) + fract; 00161 00162 /* Read third nearest value of output from the sin table */ 00163 c = tablePtr[2]; 00164 00165 /* sinVal += c*wc */ 00166 sinVal += c * wc; 00167 00168 /* Calculation of wd */ 00169 /* wd = (oneBy6)*fractCube - (oneBy6)*fract; */ 00170 fractCube = fractCube - fract; 00171 wd = ((q15_t) (((q31_t) oneBy6 * fractCube) >> 15)); 00172 00173 /* Read fourth nearest value of output from the sin table */ 00174 d = tablePtr[3]; 00175 00176 /* sinVal += d*wd; */ 00177 sinVal += d * wd; 00178 00179 /* Return the output value in 1.15(q15) format */ 00180 return ((q15_t) (sinVal >> 15u)); 00181 00182 } 00183
