| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| * |
| * $Date: 21. September 2015 |
| * $Revision: V.1.4.5 a |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_sin_f32.c |
| * |
| * Description: Fast sine calculation for floating-point values. |
| * |
| * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * - Neither the name of ARM LIMITED nor the names of its contributors |
| * may be used to endorse or promote products derived from this |
| * software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| * -------------------------------------------------------------------- */ |
| |
| #include "arm_math.h" |
| #include "arm_common_tables.h" |
| #include <math.h> |
| |
| /** |
| * @ingroup groupFastMath |
| */ |
| |
| /** |
| * @defgroup sin Sine |
| * |
| * Computes the trigonometric sine function using a combination of table lookup |
| * and linear interpolation. There are separate functions for |
| * Q15, Q31, and floating-point data types. |
| * The input to the floating-point version is in radians while the |
| * fixed-point Q15 and Q31 have a scaled input with the range |
| * [0 +0.9999] mapping to [0 2*pi). The fixed-point range is chosen so that a |
| * value of 2*pi wraps around to 0. |
| * |
| * The implementation is based on table lookup using 256 values together with linear interpolation. |
| * The steps used are: |
| * -# Calculation of the nearest integer table index |
| * -# Compute the fractional portion (fract) of the table index. |
| * -# The final result equals <code>(1.0f-fract)*a + fract*b;</code> |
| * |
| * where |
| * <pre> |
| * b=Table[index+0]; |
| * c=Table[index+1]; |
| * </pre> |
| */ |
| |
| /** |
| * @addtogroup sin |
| * @{ |
| */ |
| |
| /** |
| * @brief Fast approximation to the trigonometric sine function for floating-point data. |
| * @param[in] x input value in radians. |
| * @return sin(x). |
| */ |
| |
| float32_t arm_sin_f32( |
| float32_t x) |
| { |
| float32_t sinVal, fract, in; /* Temporary variables for input, output */ |
| uint16_t index; /* Index variable */ |
| float32_t a, b; /* Two nearest output values */ |
| int32_t n; |
| float32_t findex; |
| |
| /* input x is in radians */ |
| /* Scale the input to [0 1] range from [0 2*PI] , divide input by 2*pi */ |
| in = x * 0.159154943092f; |
| |
| /* Calculation of floor value of input */ |
| n = (int32_t) in; |
| |
| /* Make negative values towards -infinity */ |
| if(x < 0.0f) |
| { |
| n--; |
| } |
| |
| /* Map input value to [0 1] */ |
| in = in - (float32_t) n; |
| |
| /* Calculation of index of the table */ |
| findex = (float32_t) FAST_MATH_TABLE_SIZE * in; |
| if (findex >= 512.0f) { |
| findex -= 512.0f; |
| } |
| |
| index = ((uint16_t)findex) & 0x1ff; |
| |
| /* fractional value calculation */ |
| fract = findex - (float32_t) index; |
| |
| /* Read two nearest values of input value from the sin table */ |
| a = sinTable_f32[index]; |
| b = sinTable_f32[index+1]; |
| |
| /* Linear interpolation process */ |
| sinVal = (1.0f-fract)*a + fract*b; |
| |
| /* Return the output value */ |
| return (sinVal); |
| } |
| |
| /** |
| * @} end of sin group |
| */ |