CMSIS DSP library
Dependents: KL25Z_FFT_Demo Hat_Board_v5_1 KL25Z_FFT_Demo_tony KL25Z_FFT_Demo_tony ... more
Fork of mbed-dsp by
Diff: cmsis_dsp/FastMathFunctions/arm_cos_q31.c
- Revision:
- 3:7a284390b0ce
- Parent:
- 2:da51fb522205
--- a/cmsis_dsp/FastMathFunctions/arm_cos_q31.c Thu May 30 17:10:11 2013 +0100 +++ b/cmsis_dsp/FastMathFunctions/arm_cos_q31.c Fri Nov 08 13:45:10 2013 +0000 @@ -1,8 +1,8 @@ /* ---------------------------------------------------------------------- -* Copyright (C) 2010 ARM Limited. All rights reserved. +* Copyright (C) 2010-2013 ARM Limited. All rights reserved. * -* $Date: 15. February 2012 -* $Revision: V1.1.0 +* $Date: 17. January 2013 +* $Revision: V1.4.1 * * Project: CMSIS DSP Library * Title: arm_cos_q31.c @@ -11,23 +11,31 @@ * * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 * -* Version 1.1.0 2012/02/15 -* Updated with more optimizations, bug fixes and minor API changes. -* -* 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. +* 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" @@ -43,19 +51,20 @@ /** * \par - * Table Values are in Q31(1.31 Fixed point format) and generation is done in three steps - * First Generate cos values in floating point: + * Table values are in Q31 (1.31 fixed-point format) and generation is done in + * three steps. First, generate cos values in floating point: + * <pre> * tableSize = 256; - * <pre>for(n = -1; n < (tableSize + 1); n++) + * for(n = -1; n < (tableSize + 1); n++) * { * cosTable[n+1]= cos(2*pi*n/tableSize); * } </pre> * where pi value is 3.14159265358979 * \par - * Secondly Convert Floating point to Q31(Fixed point): + * Second, convert floating-point to Q31 (Fixed point): * (cosTable[i] * pow(2, 31)) * \par - * Finally Rounding to nearest integer is done + * Finally, round to the nearest integer value: * cosTable[i] += (cosTable[i] > 0 ? 0.5 :-0.5); */ @@ -133,7 +142,8 @@ * @param[in] x Scaled input value in radians. * @return cos(x). * - * The Q31 input value is in the range [0 +0.9999] and is mapped to a radian value in the range [0 2*pi), Here range excludes 2*pi. + * The Q31 input value is in the range [0 +0.9999] and is mapped to a radian + * value in the range [0 2*pi). */ q31_t arm_cos_q31(