| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| * |
| * $Date: 19. March 2015 |
| * $Revision: V.1.4.5 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_sin_cos_f32.c |
| * |
| * Description: Sine and Cosine 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" |
| |
| /** |
| * @ingroup groupController |
| */ |
| |
| /** |
| * @defgroup SinCos Sine Cosine |
| * |
| * Computes the trigonometric sine and cosine values using a combination of table lookup |
| * and linear interpolation. |
| * There are separate functions for Q31 and floating-point data types. |
| * The input to the floating-point version is in degrees while the |
| * fixed-point Q31 have a scaled input with the range |
| * [-1 0.9999] mapping to [-180 +180] degrees. |
| * |
| * The floating point function also allows values that are out of the usual range. When this happens, the function will |
| * take extra time to adjust the input value to the range of [-180 180]. |
| * |
| * The implementation is based on table lookup using 360 values together with linear interpolation. |
| * The steps used are: |
| * -# Calculation of the nearest integer table index. |
| * -# Compute the fractional portion (fract) of the input. |
| * -# Fetch the value corresponding to \c index from sine table to \c y0 and also value from \c index+1 to \c y1. |
| * -# Sine value is computed as <code> *psinVal = y0 + (fract * (y1 - y0))</code>. |
| * -# Fetch the value corresponding to \c index from cosine table to \c y0 and also value from \c index+1 to \c y1. |
| * -# Cosine value is computed as <code> *pcosVal = y0 + (fract * (y1 - y0))</code>. |
| */ |
| |
| /** |
| * @addtogroup SinCos |
| * @{ |
| */ |
| |
| /** |
| * @brief Floating-point sin_cos function. |
| * @param[in] theta input value in degrees |
| * @param[out] *pSinVal points to the processed sine output. |
| * @param[out] *pCosVal points to the processed cos output. |
| * @return none. |
| */ |
| |
| void arm_sin_cos_f32( |
| float32_t theta, |
| float32_t * pSinVal, |
| float32_t * pCosVal) |
| { |
| float32_t fract, in; /* Temporary variables for input, output */ |
| uint16_t indexS, indexC; /* Index variable */ |
| float32_t f1, f2, d1, d2; /* Two nearest output values */ |
| int32_t n; |
| float32_t findex, Dn, Df, temp; |
| |
| /* input x is in degrees */ |
| /* Scale the input, divide input by 360, for cosine add 0.25 (pi/2) to read sine table */ |
| in = theta * 0.00277777777778f; |
| |
| /* Calculation of floor value of input */ |
| n = (int32_t) in; |
| |
| /* Make negative values towards -infinity */ |
| if(in < 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; |
| indexS = ((uint16_t)findex) & 0x1ff; |
| indexC = (indexS + (FAST_MATH_TABLE_SIZE / 4)) & 0x1ff; |
| |
| /* fractional value calculation */ |
| fract = findex - (float32_t) indexS; |
| |
| /* Read two nearest values of input value from the cos & sin tables */ |
| f1 = sinTable_f32[indexC+0]; |
| f2 = sinTable_f32[indexC+1]; |
| d1 = -sinTable_f32[indexS+0]; |
| d2 = -sinTable_f32[indexS+1]; |
| |
| Dn = 0.0122718463030f; // delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE |
| Df = f2 - f1; // delta between the values of the functions |
| temp = Dn*(d1 + d2) - 2*Df; |
| temp = fract*temp + (3*Df - (d2 + 2*d1)*Dn); |
| temp = fract*temp + d1*Dn; |
| |
| /* Calculation of cosine value */ |
| *pCosVal = fract*temp + f1; |
| |
| /* Read two nearest values of input value from the cos & sin tables */ |
| f1 = sinTable_f32[indexS+0]; |
| f2 = sinTable_f32[indexS+1]; |
| d1 = sinTable_f32[indexC+0]; |
| d2 = sinTable_f32[indexC+1]; |
| |
| Df = f2 - f1; // delta between the values of the functions |
| temp = Dn*(d1 + d2) - 2*Df; |
| temp = fract*temp + (3*Df - (d2 + 2*d1)*Dn); |
| temp = fract*temp + d1*Dn; |
| |
| /* Calculation of sine value */ |
| *pSinVal = fract*temp + f1; |
| } |
| /** |
| * @} end of SinCos group |
| */ |