Eli Hughes / CMSIS_DSP_401

V4.0.1 of the ARM CMSIS DSP libraries. Note that arm_bitreversal2.s, arm_cfft_f32.c and arm_rfft_fast_f32.c had to be removed. arm_bitreversal2.s will not assemble with the online tools. So, the fast f32 FFT functions are not yet available. All the other FFT functions are available.

Dependents:   MPU9150_Example fir_f32 fir_f32 MPU9150_nucleo_noni2cdev ... more

FastMathFunctions/arm_cos_f32.c@0:3d9c67d97d6f, 2014-07-28 (annotated)

Committer:
emh203
Date:
Mon Jul 28 15:03:15 2014 +0000
Revision:
0:3d9c67d97d6f
1st working commit.   Had to remove arm_bitreversal2.s     arm_cfft_f32.c and arm_rfft_fast_f32.c.    The .s will not assemble.      For now I removed these functions so we could at least have a library for the other functions.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emh203 0:3d9c67d97d6f 1 /* ----------------------------------------------------------------------
emh203 0:3d9c67d97d6f 2 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
emh203 0:3d9c67d97d6f 3 *
emh203 0:3d9c67d97d6f 4 * $Date: 12. March 2014
emh203 0:3d9c67d97d6f 5 * $Revision: V1.4.3
emh203 0:3d9c67d97d6f 6 *
emh203 0:3d9c67d97d6f 7 * Project: CMSIS DSP Library
emh203 0:3d9c67d97d6f 8 * Title: arm_cos_f32.c
emh203 0:3d9c67d97d6f 9 *
emh203 0:3d9c67d97d6f 10 * Description: Fast cosine calculation for floating-point values.
emh203 0:3d9c67d97d6f 11 *
emh203 0:3d9c67d97d6f 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emh203 0:3d9c67d97d6f 13 *
emh203 0:3d9c67d97d6f 14 * Redistribution and use in source and binary forms, with or without
emh203 0:3d9c67d97d6f 15 * modification, are permitted provided that the following conditions
emh203 0:3d9c67d97d6f 16 * are met:
emh203 0:3d9c67d97d6f 17 * - Redistributions of source code must retain the above copyright
emh203 0:3d9c67d97d6f 18 * notice, this list of conditions and the following disclaimer.
emh203 0:3d9c67d97d6f 19 * - Redistributions in binary form must reproduce the above copyright
emh203 0:3d9c67d97d6f 20 * notice, this list of conditions and the following disclaimer in
emh203 0:3d9c67d97d6f 21 * the documentation and/or other materials provided with the
emh203 0:3d9c67d97d6f 22 * distribution.
emh203 0:3d9c67d97d6f 23 * - Neither the name of ARM LIMITED nor the names of its contributors
emh203 0:3d9c67d97d6f 24 * may be used to endorse or promote products derived from this
emh203 0:3d9c67d97d6f 25 * software without specific prior written permission.
emh203 0:3d9c67d97d6f 26 *
emh203 0:3d9c67d97d6f 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
emh203 0:3d9c67d97d6f 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
emh203 0:3d9c67d97d6f 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
emh203 0:3d9c67d97d6f 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
emh203 0:3d9c67d97d6f 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
emh203 0:3d9c67d97d6f 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
emh203 0:3d9c67d97d6f 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
emh203 0:3d9c67d97d6f 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
emh203 0:3d9c67d97d6f 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
emh203 0:3d9c67d97d6f 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
emh203 0:3d9c67d97d6f 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
emh203 0:3d9c67d97d6f 38 * POSSIBILITY OF SUCH DAMAGE.
emh203 0:3d9c67d97d6f 39 * -------------------------------------------------------------------- */
emh203 0:3d9c67d97d6f 40
emh203 0:3d9c67d97d6f 41 #include "arm_math.h"
emh203 0:3d9c67d97d6f 42 #include "arm_common_tables.h"
emh203 0:3d9c67d97d6f 43 /**
emh203 0:3d9c67d97d6f 44 * @ingroup groupFastMath
emh203 0:3d9c67d97d6f 45 */
emh203 0:3d9c67d97d6f 46
emh203 0:3d9c67d97d6f 47 /**
emh203 0:3d9c67d97d6f 48 * @defgroup cos Cosine
emh203 0:3d9c67d97d6f 49 *
emh203 0:3d9c67d97d6f 50 * Computes the trigonometric cosine function using a combination of table lookup
emh203 0:3d9c67d97d6f 51 * and cubic interpolation. There are separate functions for
emh203 0:3d9c67d97d6f 52 * Q15, Q31, and floating-point data types.
emh203 0:3d9c67d97d6f 53 * The input to the floating-point version is in radians while the
emh203 0:3d9c67d97d6f 54 * fixed-point Q15 and Q31 have a scaled input with the range
emh203 0:3d9c67d97d6f 55 * [0 +0.9999] mapping to [0 2*pi). The fixed-point range is chosen so that a
emh203 0:3d9c67d97d6f 56 * value of 2*pi wraps around to 0.
emh203 0:3d9c67d97d6f 57 *
emh203 0:3d9c67d97d6f 58 * The implementation is based on table lookup using 256 values together with cubic interpolation.
emh203 0:3d9c67d97d6f 59 * The steps used are:
emh203 0:3d9c67d97d6f 60 * -# Calculation of the nearest integer table index
emh203 0:3d9c67d97d6f 61 * -# Fetch the four table values a, b, c, and d
emh203 0:3d9c67d97d6f 62 * -# Compute the fractional portion (fract) of the table index.
emh203 0:3d9c67d97d6f 63 * -# Calculation of wa, wb, wc, wd
emh203 0:3d9c67d97d6f 64 * -# The final result equals <code>a*wa + b*wb + c*wc + d*wd</code>
emh203 0:3d9c67d97d6f 65 *
emh203 0:3d9c67d97d6f 66 * where
emh203 0:3d9c67d97d6f 67 * <pre>
emh203 0:3d9c67d97d6f 68 * a=Table[index-1];
emh203 0:3d9c67d97d6f 69 * b=Table[index+0];
emh203 0:3d9c67d97d6f 70 * c=Table[index+1];
emh203 0:3d9c67d97d6f 71 * d=Table[index+2];
emh203 0:3d9c67d97d6f 72 * </pre>
emh203 0:3d9c67d97d6f 73 * and
emh203 0:3d9c67d97d6f 74 * <pre>
emh203 0:3d9c67d97d6f 75 * wa=-(1/6)*fract.^3 + (1/2)*fract.^2 - (1/3)*fract;
emh203 0:3d9c67d97d6f 76 * wb=(1/2)*fract.^3 - fract.^2 - (1/2)*fract + 1;
emh203 0:3d9c67d97d6f 77 * wc=-(1/2)*fract.^3+(1/2)*fract.^2+fract;
emh203 0:3d9c67d97d6f 78 * wd=(1/6)*fract.^3 - (1/6)*fract;
emh203 0:3d9c67d97d6f 79 * </pre>
emh203 0:3d9c67d97d6f 80 */
emh203 0:3d9c67d97d6f 81
emh203 0:3d9c67d97d6f 82 /**
emh203 0:3d9c67d97d6f 83 * @addtogroup cos
emh203 0:3d9c67d97d6f 84 * @{
emh203 0:3d9c67d97d6f 85 */
emh203 0:3d9c67d97d6f 86
emh203 0:3d9c67d97d6f 87 /**
emh203 0:3d9c67d97d6f 88 * @brief Fast approximation to the trigonometric cosine function for floating-point data.
emh203 0:3d9c67d97d6f 89 * @param[in] x input value in radians.
emh203 0:3d9c67d97d6f 90 * @return cos(x).
emh203 0:3d9c67d97d6f 91 */
emh203 0:3d9c67d97d6f 92
emh203 0:3d9c67d97d6f 93 float32_t arm_cos_f32(
emh203 0:3d9c67d97d6f 94 float32_t x)
emh203 0:3d9c67d97d6f 95 {
emh203 0:3d9c67d97d6f 96 float32_t cosVal, fract, in; /* Temporary variables for input, output */
emh203 0:3d9c67d97d6f 97 uint16_t index; /* Index variable */
emh203 0:3d9c67d97d6f 98 float32_t a, b; /* Two nearest output values */
emh203 0:3d9c67d97d6f 99 int32_t n;
emh203 0:3d9c67d97d6f 100 float32_t findex;
emh203 0:3d9c67d97d6f 101
emh203 0:3d9c67d97d6f 102 /* input x is in radians */
emh203 0:3d9c67d97d6f 103 /* Scale the input to [0 1] range from [0 2*PI] , divide input by 2*pi, add 0.25 (pi/2) to read sine table */
emh203 0:3d9c67d97d6f 104 in = x * 0.159154943092f + 0.25f;
emh203 0:3d9c67d97d6f 105
emh203 0:3d9c67d97d6f 106 /* Calculation of floor value of input */
emh203 0:3d9c67d97d6f 107 n = (int32_t) in;
emh203 0:3d9c67d97d6f 108
emh203 0:3d9c67d97d6f 109 /* Make negative values towards -infinity */
emh203 0:3d9c67d97d6f 110 if(in < 0.0f)
emh203 0:3d9c67d97d6f 111 {
emh203 0:3d9c67d97d6f 112 n--;
emh203 0:3d9c67d97d6f 113 }
emh203 0:3d9c67d97d6f 114
emh203 0:3d9c67d97d6f 115 /* Map input value to [0 1] */
emh203 0:3d9c67d97d6f 116 in = in - (float32_t) n;
emh203 0:3d9c67d97d6f 117
emh203 0:3d9c67d97d6f 118 /* Calculation of index of the table */
emh203 0:3d9c67d97d6f 119 findex = (float32_t) FAST_MATH_TABLE_SIZE * in;
emh203 0:3d9c67d97d6f 120 index = ((uint16_t)findex) & 0x1ff;
emh203 0:3d9c67d97d6f 121
emh203 0:3d9c67d97d6f 122 /* fractional value calculation */
emh203 0:3d9c67d97d6f 123 fract = findex - (float32_t) index;
emh203 0:3d9c67d97d6f 124
emh203 0:3d9c67d97d6f 125 /* Read two nearest values of input value from the cos table */
emh203 0:3d9c67d97d6f 126 a = sinTable_f32[index];
emh203 0:3d9c67d97d6f 127 b = sinTable_f32[index+1];
emh203 0:3d9c67d97d6f 128
emh203 0:3d9c67d97d6f 129 /* Linear interpolation process */
emh203 0:3d9c67d97d6f 130 cosVal = (1.0f-fract)*a + fract*b;
emh203 0:3d9c67d97d6f 131
emh203 0:3d9c67d97d6f 132 /* Return the output value */
emh203 0:3d9c67d97d6f 133 return (cosVal);
emh203 0:3d9c67d97d6f 134 }
emh203 0:3d9c67d97d6f 135
emh203 0:3d9c67d97d6f 136 /**
emh203 0:3d9c67d97d6f 137 * @} end of cos group
emh203 0:3d9c67d97d6f 138 */