arm_negate_f32.c

00001 /* ----------------------------------------------------------------------  
00002 * Copyright (C) 2010 ARM Limited. All rights reserved.  
00003 *  
00004 * $Date:        29. November 2010  
00005 * $Revision:    V1.0.3  
00006 *  
00007 * Project:      CMSIS DSP Library  
00008 * Title:        arm_negate_f32.c  
00009 *  
00010 * Description:  Negates floating-point vectors.  
00011 *  
00012 * Target Processor: Cortex-M4/Cortex-M3
00013 *  
00014 * Version 1.0.3 2010/11/29 
00015 *    Re-organized the CMSIS folders and updated documentation.  
00016 *   
00017 * Version 1.0.2 2010/11/11  
00018 *    Documentation updated.   
00019 *  
00020 * Version 1.0.1 2010/10/05   
00021 *    Production release and review comments incorporated.  
00022 *  
00023 * Version 1.0.0 2010/09/20   
00024 *    Production release and review comments incorporated.  
00025 *  
00026 * Version 0.0.7  2010/06/10   
00027 *    Misra-C changes done  
00028 * ---------------------------------------------------------------------------- */ 
00029  
00030 #include "arm_math.h" 
00031  
00032 /**  
00033  * @ingroup groupMath  
00034  */ 
00035  
00036 /**  
00037  * @defgroup negate Vector Negate  
00038  *  
00039  * Negates the elements of a vector.  
00040  *  
00041  * <pre>  
00042  *     pDst[n] = -pSrc[n],   0 <= n < blockSize.  
00043  * </pre>  
00044  */ 
00045  
00046 /**  
00047  * @addtogroup negate  
00048  * @{  
00049  */ 
00050  
00051 /**  
00052  * @brief  Negates the elements of a floating-point vector.  
00053  * @param  *pSrc points to the input vector  
00054  * @param  *pDst points to the output vector  
00055  * @param  blockSize number of samples in the vector  
00056  * @return none.  
00057  */ 
00058  
00059 void arm_negate_f32( 
00060   float32_t * pSrc, 
00061   float32_t * pDst, 
00062   uint32_t blockSize) 
00063 { 
00064   uint32_t blkCnt;                               /* loop counter */ 
00065  
00066   /*loop Unrolling */ 
00067   blkCnt = blockSize >> 2u; 
00068  
00069   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.  
00070    ** a second loop below computes the remaining 1 to 3 samples. */ 
00071   while(blkCnt > 0u) 
00072   { 
00073     /* C = ~A */ 
00074     /* Negate and then store the results in the destination buffer. */ 
00075     *pDst++ = -*pSrc++; 
00076     *pDst++ = -*pSrc++; 
00077     *pDst++ = -*pSrc++; 
00078     *pDst++ = -*pSrc++; 
00079  
00080     /* Decrement the loop counter */ 
00081     blkCnt--; 
00082   } 
00083  
00084   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.  
00085    ** No loop unrolling is used. */ 
00086   blkCnt = blockSize % 0x4u; 
00087  
00088   while(blkCnt > 0u) 
00089   { 
00090     /* C = ~A */ 
00091     /* Negate and then store the results in the destination buffer. */ 
00092     *pDst++ = -*pSrc++; 
00093  
00094     /* Decrement the loop counter */ 
00095     blkCnt--; 
00096   } 
00097 } 
00098  
00099 /**  
00100  * @} end of negate group  
00101  */