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Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_sin_q15.c')
-rw-r--r-- | Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_sin_q15.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_sin_q15.c b/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_sin_q15.c new file mode 100644 index 0000000..81f0d62 --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_sin_q15.c @@ -0,0 +1,83 @@ +/* ---------------------------------------------------------------------- + * Project: CMSIS DSP Library + * Title: arm_sin_q15.c + * Description: Fast sine calculation for Q15 values + * + * $Date: 23 April 2021 + * $Revision: V1.9.0 + * + * Target Processor: Cortex-M and Cortex-A cores + * -------------------------------------------------------------------- */ +/* + * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved. + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed under the Apache License, Version 2.0 (the License); you may + * not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an AS IS BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "dsp/fast_math_functions.h" +#include "arm_common_tables.h" + +/** + @ingroup groupFastMath + */ + +/** + @addtogroup sin + @{ + */ + +/** + @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 +0.9999] and is mapped to a radian value in the range [0 2*PI). + */ + +q15_t arm_sin_q15( + q15_t x) +{ + q15_t sinVal; /* Temporary input, output variables */ + int32_t index; /* Index variable */ + q15_t a, b; /* Two nearest output values */ + q15_t fract; /* Temporary values for fractional values */ + + + if (x < 0) + { /* convert negative numbers to corresponding positive ones */ + x = (uint16_t)x + 0x8000; + } + + /* Calculate the nearest index */ + index = (uint32_t)x >> FAST_MATH_Q15_SHIFT; + + /* Calculation of fractional value */ + fract = (x - (index << FAST_MATH_Q15_SHIFT)) << 9; + + /* Read two nearest values of input value from the sin table */ + a = sinTable_q15[index]; + b = sinTable_q15[index+1]; + + /* Linear interpolation process */ + sinVal = (q31_t) (0x8000 - fract) * a >> 16; + sinVal = (q15_t) ((((q31_t) sinVal << 16) + ((q31_t) fract * b)) >> 16); + + /* Return output value */ + return (sinVal << 1); +} + +/** + @} end of sin group + */ |