From 96d6da4e252b06dcfdc041e7df23e86161c33007 Mon Sep 17 00:00:00 2001 From: rihab kouki Date: Tue, 28 Jul 2020 11:24:49 +0100 Subject: Official ARM version: v5.6.0 --- DSP/Source/FastMathFunctions/arm_cos_q15.c | 44 +++++++++++++++--------------- 1 file changed, 22 insertions(+), 22 deletions(-) (limited to 'DSP/Source/FastMathFunctions/arm_cos_q15.c') diff --git a/DSP/Source/FastMathFunctions/arm_cos_q15.c b/DSP/Source/FastMathFunctions/arm_cos_q15.c index 7fa2e18..3bb829c 100644 --- a/DSP/Source/FastMathFunctions/arm_cos_q15.c +++ b/DSP/Source/FastMathFunctions/arm_cos_q15.c @@ -3,13 +3,13 @@ * Title: arm_cos_q15.c * Description: Fast cosine calculation for Q15 values * - * $Date: 27. January 2017 - * $Revision: V.1.5.1 + * $Date: 18. March 2019 + * $Revision: V1.6.0 * * Target Processor: Cortex-M cores * -------------------------------------------------------------------- */ /* - * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved. + * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved. * * SPDX-License-Identifier: Apache-2.0 * @@ -30,36 +30,35 @@ #include "arm_common_tables.h" /** - * @ingroup groupFastMath + @ingroup groupFastMath */ - /** - * @addtogroup cos - * @{ +/** + @addtogroup cos + @{ */ /** - * @brief Fast approximation to the trigonometric cosine function for Q15 data. - * @param[in] x Scaled input value in radians. - * @return cos(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). + @brief Fast approximation to the trigonometric cosine function for Q15 data. + @param[in] x Scaled input value in radians + @return cos(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_cos_q15( q15_t x) { - q15_t cosVal; /* Temporary variables for input, output */ - int32_t index; /* Index variables */ - q15_t a, b; /* Four nearest output values */ + q15_t cosVal; /* 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 */ /* add 0.25 (pi/2) to read sine table */ x = (uint16_t)x + 0x2000; if (x < 0) - { /* convert negative numbers to corresponding positive ones */ - x = (uint16_t)x + 0x8000; + { /* convert negative numbers to corresponding positive ones */ + x = (uint16_t)x + 0x8000; } /* Calculate the nearest index */ @@ -73,12 +72,13 @@ q15_t arm_cos_q15( b = sinTable_q15[index+1]; /* Linear interpolation process */ - cosVal = (q31_t)(0x8000-fract)*a >> 16; - cosVal = (q15_t)((((q31_t)cosVal << 16) + ((q31_t)fract*b)) >> 16); + cosVal = (q31_t) (0x8000 - fract) * a >> 16; + cosVal = (q15_t) ((((q31_t) cosVal << 16) + ((q31_t) fract * b)) >> 16); - return cosVal << 1; + /* Return output value */ + return (cosVal << 1); } /** - * @} end of cos group + @} end of cos group */ -- cgit