arm_sin_q15.c
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| text/x-c
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CLexer
r71 | /* ---------------------------------------------------------------------- | |||
* Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
* | ||||
* $Date: 15. July 2011 | ||||
* $Revision: V1.0.10 | ||||
* | ||||
* Project: CMSIS DSP Library | ||||
* Title: arm_sin_q15.c | ||||
* | ||||
* Description: Fast sine calculation for Q15 values. | ||||
* | ||||
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | ||||
* | ||||
* 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 | ||||
*/ | ||||
/** | ||||
* @addtogroup sin | ||||
* @{ | ||||
*/ | ||||
/** | ||||
* \par | ||||
* Example code for Generation of Q15 Sin Table: | ||||
* \par | ||||
* <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 | ||||
* Convert Floating point to Q15(Fixed point): | ||||
* (sinTable[i] * pow(2, 15)) | ||||
* \par | ||||
* rounding to nearest integer is done | ||||
* 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. | ||||
* @return sin(x). | ||||
* | ||||
* The Q15 input value is in the range [0 +1) and is mapped to a radian value in the range [0 2*pi). | ||||
*/ | ||||
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; | ||||
/* Calculate the nearest index */ | ||||
index = (int32_t) in / tableSpacing; | ||||
/* Calculate the nearest value of input */ | ||||
in2 = (q15_t) ((index) * tableSpacing); | ||||
/* 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); | ||||
/* 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; | ||||
/* 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++; | ||||
/* 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; | ||||
/* Return the output value in 1.15(q15) format */ | ||||
return ((q15_t) (sinVal >> 15u)); | ||||
} | ||||
/** | ||||
* @} end of sin group | ||||
*/ | ||||