arm_abs_f32.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        17. January 2013
00005 * $Revision:    V1.4.1
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_abs_f32.c    
00009 *    
00010 * Description:  Vector absolute value.    
00011 *    
00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
00013 *  
00014 * Redistribution and use in source and binary forms, with or without 
00015 * modification, are permitted provided that the following conditions
00016 * are met:
00017 *   - Redistributions of source code must retain the above copyright
00018 *     notice, this list of conditions and the following disclaimer.
00019 *   - Redistributions in binary form must reproduce the above copyright
00020 *     notice, this list of conditions and the following disclaimer in
00021 *     the documentation and/or other materials provided with the 
00022 *     distribution.
00023 *   - Neither the name of ARM LIMITED nor the names of its contributors
00024 *     may be used to endorse or promote products derived from this
00025 *     software without specific prior written permission.
00026 *
00027 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00028 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00029 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00030 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
00031 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00032 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00033 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00034 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00035 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00036 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00037 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00038 * POSSIBILITY OF SUCH DAMAGE.   
00039 * ---------------------------------------------------------------------------- */
00040 
00041 #include "arm_math.h"
00042 #include <math.h>
00043 
00044 /**        
00045  * @ingroup groupMath        
00046  */
00047 
00048 /**        
00049  * @defgroup BasicAbs Vector Absolute Value        
00050  *        
00051  * Computes the absolute value of a vector on an element-by-element basis.        
00052  *        
00053  * <pre>        
00054  *     pDst[n] = abs(pSrc[n]),   0 <= n < blockSize.        
00055  * </pre>        
00056  *        
00057  * The functions support in-place computation allowing the source and
00058  * destination pointers to reference the same memory buffer.
00059  * There are separate functions for floating-point, Q7, Q15, and Q31 data types.
00060  */
00061 
00062 /**        
00063  * @addtogroup BasicAbs        
00064  * @{        
00065  */
00066 
00067 /**        
00068  * @brief Floating-point vector absolute value.        
00069  * @param[in]       *pSrc points to the input buffer        
00070  * @param[out]      *pDst points to the output buffer        
00071  * @param[in]       blockSize number of samples in each vector        
00072  * @return none.        
00073  */
00074 
00075 void arm_abs_f32(
00076   float32_t * pSrc,
00077   float32_t * pDst,
00078   uint32_t blockSize)
00079 {
00080   uint32_t blkCnt;                               /* loop counter */
00081 
00082 #ifndef ARM_MATH_CM0_FAMILY
00083 
00084   /* Run the below code for Cortex-M4 and Cortex-M3 */
00085   float32_t in1, in2, in3, in4;                  /* temporary variables */
00086 
00087   /*loop Unrolling */
00088   blkCnt = blockSize >> 2u;
00089 
00090   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
00091    ** a second loop below computes the remaining 1 to 3 samples. */
00092   while(blkCnt > 0u)
00093   {
00094     /* C = |A| */
00095     /* Calculate absolute and then store the results in the destination buffer. */
00096     /* read sample from source */
00097     in1 = *pSrc;
00098     in2 = *(pSrc + 1);
00099     in3 = *(pSrc + 2);
00100 
00101     /* find absolute value */
00102     in1 = fabsf(in1);
00103 
00104     /* read sample from source */
00105     in4 = *(pSrc + 3);
00106 
00107     /* find absolute value */
00108     in2 = fabsf(in2);
00109 
00110     /* read sample from source */
00111     *pDst = in1;
00112 
00113     /* find absolute value */
00114     in3 = fabsf(in3);
00115 
00116     /* find absolute value */
00117     in4 = fabsf(in4);
00118 
00119     /* store result to destination */
00120     *(pDst + 1) = in2;
00121 
00122     /* store result to destination */
00123     *(pDst + 2) = in3;
00124 
00125     /* store result to destination */
00126     *(pDst + 3) = in4;
00127 
00128 
00129     /* Update source pointer to process next sampels */
00130     pSrc += 4u;
00131 
00132     /* Update destination pointer to process next sampels */
00133     pDst += 4u;
00134 
00135     /* Decrement the loop counter */
00136     blkCnt--;
00137   }
00138 
00139   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.    
00140    ** No loop unrolling is used. */
00141   blkCnt = blockSize % 0x4u;
00142 
00143 #else
00144 
00145   /* Run the below code for Cortex-M0 */
00146 
00147   /* Initialize blkCnt with number of samples */
00148   blkCnt = blockSize;
00149 
00150 #endif /*   #ifndef ARM_MATH_CM0_FAMILY   */
00151 
00152   while(blkCnt > 0u)
00153   {
00154     /* C = |A| */
00155     /* Calculate absolute and then store the results in the destination buffer. */
00156     *pDst++ = fabsf(*pSrc++);
00157 
00158     /* Decrement the loop counter */
00159     blkCnt--;
00160   }
00161 }
00162 
00163 /**        
00164  * @} end of BasicAbs group        
00165  */