CMSIS DSP library
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Diff: cmsis_dsp/FastMathFunctions/arm_sin_q15.c
- Revision:
- 5:3762170b6d4d
- Parent:
- 3:7a284390b0ce
--- a/cmsis_dsp/FastMathFunctions/arm_sin_q15.c Mon Jun 23 09:30:09 2014 +0100 +++ b/cmsis_dsp/FastMathFunctions/arm_sin_q15.c Fri Nov 20 08:45:18 2015 +0000 @@ -1,8 +1,8 @@ /* ---------------------------------------------------------------------- -* Copyright (C) 2010-2013 ARM Limited. All rights reserved. +* Copyright (C) 2010-2014 ARM Limited. All rights reserved. * -* $Date: 17. January 2013 -* $Revision: V1.4.1 +* $Date: 19. March 2015 +* $Revision: V.1.4.5 * * Project: CMSIS DSP Library * Title: arm_sin_q15.c @@ -39,6 +39,7 @@ * -------------------------------------------------------------------- */ #include "arm_math.h" +#include "arm_common_tables.h" /** * @ingroup groupFastMath @@ -49,63 +50,6 @@ * @{ */ - -/** -* \par - * Table values are in Q15 (1.15 fixed-point format) and generation is done in - * three steps. First, generate sin values in floating point: - * <pre> - * tableSize = 256; - * for(n = -1; n < (tableSize + 1); n++) - * { - * sinTable[n+1]= sin(2*pi*n/tableSize); - * } </pre> - * where pi value is 3.14159265358979 - * \par - * Second, convert floating-point to Q15 (fixed-point): - * (sinTable[i] * pow(2, 15)) - * \par - * Finally, round to the nearest integer value: - * sinTable[i] += (sinTable[i] > 0 ? 0.5 :-0.5); -*/ - -static const q15_t sinTableQ15[259] = { - 0xfcdc, 0x0, 0x324, 0x648, 0x96b, 0xc8c, 0xfab, 0x12c8, - 0x15e2, 0x18f9, 0x1c0c, 0x1f1a, 0x2224, 0x2528, 0x2827, 0x2b1f, - 0x2e11, 0x30fc, 0x33df, 0x36ba, 0x398d, 0x3c57, 0x3f17, 0x41ce, - 0x447b, 0x471d, 0x49b4, 0x4c40, 0x4ec0, 0x5134, 0x539b, 0x55f6, - 0x5843, 0x5a82, 0x5cb4, 0x5ed7, 0x60ec, 0x62f2, 0x64e9, 0x66d0, - 0x68a7, 0x6a6e, 0x6c24, 0x6dca, 0x6f5f, 0x70e3, 0x7255, 0x73b6, - 0x7505, 0x7642, 0x776c, 0x7885, 0x798a, 0x7a7d, 0x7b5d, 0x7c2a, - 0x7ce4, 0x7d8a, 0x7e1e, 0x7e9d, 0x7f0a, 0x7f62, 0x7fa7, 0x7fd9, - 0x7ff6, 0x7fff, 0x7ff6, 0x7fd9, 0x7fa7, 0x7f62, 0x7f0a, 0x7e9d, - 0x7e1e, 0x7d8a, 0x7ce4, 0x7c2a, 0x7b5d, 0x7a7d, 0x798a, 0x7885, - 0x776c, 0x7642, 0x7505, 0x73b6, 0x7255, 0x70e3, 0x6f5f, 0x6dca, - 0x6c24, 0x6a6e, 0x68a7, 0x66d0, 0x64e9, 0x62f2, 0x60ec, 0x5ed7, - 0x5cb4, 0x5a82, 0x5843, 0x55f6, 0x539b, 0x5134, 0x4ec0, 0x4c40, - 0x49b4, 0x471d, 0x447b, 0x41ce, 0x3f17, 0x3c57, 0x398d, 0x36ba, - 0x33df, 0x30fc, 0x2e11, 0x2b1f, 0x2827, 0x2528, 0x2224, 0x1f1a, - 0x1c0c, 0x18f9, 0x15e2, 0x12c8, 0xfab, 0xc8c, 0x96b, 0x648, - 0x324, 0x0, 0xfcdc, 0xf9b8, 0xf695, 0xf374, 0xf055, 0xed38, - 0xea1e, 0xe707, 0xe3f4, 0xe0e6, 0xdddc, 0xdad8, 0xd7d9, 0xd4e1, - 0xd1ef, 0xcf04, 0xcc21, 0xc946, 0xc673, 0xc3a9, 0xc0e9, 0xbe32, - 0xbb85, 0xb8e3, 0xb64c, 0xb3c0, 0xb140, 0xaecc, 0xac65, 0xaa0a, - 0xa7bd, 0xa57e, 0xa34c, 0xa129, 0x9f14, 0x9d0e, 0x9b17, 0x9930, - 0x9759, 0x9592, 0x93dc, 0x9236, 0x90a1, 0x8f1d, 0x8dab, 0x8c4a, - 0x8afb, 0x89be, 0x8894, 0x877b, 0x8676, 0x8583, 0x84a3, 0x83d6, - 0x831c, 0x8276, 0x81e2, 0x8163, 0x80f6, 0x809e, 0x8059, 0x8027, - 0x800a, 0x8000, 0x800a, 0x8027, 0x8059, 0x809e, 0x80f6, 0x8163, - 0x81e2, 0x8276, 0x831c, 0x83d6, 0x84a3, 0x8583, 0x8676, 0x877b, - 0x8894, 0x89be, 0x8afb, 0x8c4a, 0x8dab, 0x8f1d, 0x90a1, 0x9236, - 0x93dc, 0x9592, 0x9759, 0x9930, 0x9b17, 0x9d0e, 0x9f14, 0xa129, - 0xa34c, 0xa57e, 0xa7bd, 0xaa0a, 0xac65, 0xaecc, 0xb140, 0xb3c0, - 0xb64c, 0xb8e3, 0xbb85, 0xbe32, 0xc0e9, 0xc3a9, 0xc673, 0xc946, - 0xcc21, 0xcf04, 0xd1ef, 0xd4e1, 0xd7d9, 0xdad8, 0xdddc, 0xe0e6, - 0xe3f4, 0xe707, 0xea1e, 0xed38, 0xf055, 0xf374, 0xf695, 0xf9b8, - 0xfcdc, 0x0, 0x324 -}; - - /** * @brief Fast approximation to the trigonometric sine function for Q15 data. * @param[in] x Scaled input value in radians. @@ -117,98 +61,26 @@ q15_t arm_sin_q15( q15_t x) { - q31_t sinVal; /* Temporary variables output */ - q15_t *tablePtr; /* Pointer to table */ - q15_t fract, in, in2; /* Temporary variables for input, output */ - q31_t wa, wb, wc, wd; /* Cubic interpolation coefficients */ - q15_t a, b, c, d; /* Four nearest output values */ - q15_t fractCube, fractSquare; /* Temporary values for fractional value */ - q15_t oneBy6 = 0x1555; /* Fixed point value of 1/6 */ - q15_t tableSpacing = TABLE_SPACING_Q15; /* Table spacing */ - int32_t index; /* Index variable */ - - in = x; + q15_t sinVal; /* Temporary variables for input, output */ + int32_t index; /* Index variables */ + q15_t a, b; /* Four nearest output values */ + q15_t fract; /* Temporary values for fractional values */ /* Calculate the nearest index */ - index = (int32_t) in / tableSpacing; - - /* Calculate the nearest value of input */ - in2 = (q15_t) ((index) * tableSpacing); + index = (uint32_t)x >> FAST_MATH_Q15_SHIFT; /* Calculation of fractional value */ - fract = (in - in2) << 8; - - /* fractSquare = fract * fract */ - fractSquare = (q15_t) ((fract * fract) >> 15); - - /* fractCube = fract * fract * fract */ - fractCube = (q15_t) ((fractSquare * fract) >> 15); + fract = (x - (index << FAST_MATH_Q15_SHIFT)) << 9; - /* Checking min and max index of table */ - if(index < 0) - { - index = 0; - } - else if(index > 256) - { - index = 256; - } - - /* Initialise table pointer */ - tablePtr = (q15_t *) & sinTableQ15[index]; - - /* Cubic interpolation process */ - /* Calculation of wa */ - /* wa = -(oneBy6)*fractCube + (fractSquare >> 1u) - (0x2AAA)*fract; */ - wa = (q31_t) oneBy6 *fractCube; - wa += (q31_t) 0x2AAA *fract; - wa = -(wa >> 15); - wa += ((q31_t) fractSquare >> 1u); - - /* Read first nearest value of output from the sin table */ - a = *tablePtr++; - - /* sinVal = a * wa */ - sinVal = a * wa; + /* Read two nearest values of input value from the sin table */ + a = sinTable_q15[index]; + b = sinTable_q15[index+1]; - /* Calculation of wb */ - wb = (((q31_t) fractCube >> 1u) - (q31_t) fractSquare) - - (((q31_t) fract >> 1u) - 0x7FFF); - - /* Read second nearest value of output from the sin table */ - b = *tablePtr++; - - /* sinVal += b*wb */ - sinVal += b * wb; - - - /* Calculation of wc */ - wc = -(q31_t) fractCube + fractSquare; - wc = (wc >> 1u) + fract; - - /* Read third nearest value of output from the sin table */ - c = *tablePtr++; + /* Linear interpolation process */ + sinVal = (q31_t)(0x8000-fract)*a >> 16; + sinVal = (q15_t)((((q31_t)sinVal << 16) + ((q31_t)fract*b)) >> 16); - /* sinVal += c*wc */ - sinVal += c * wc; - - /* Calculation of wd */ - /* wd = (oneBy6)*fractCube - (oneBy6)*fract; */ - fractCube = fractCube - fract; - wd = ((q15_t) (((q31_t) oneBy6 * fractCube) >> 15)); - - /* Read fourth nearest value of output from the sin table */ - d = *tablePtr++; - - /* sinVal += d*wd; */ - sinVal += d * wd; - - /* Convert output value in 1.15(q15) format and saturate */ - sinVal = __SSAT((sinVal >> 15), 16); - - /* Return the output value in 1.15(q15) format */ - return ((q15_t) sinVal); - + return sinVal << 1; } /**