CMSIS DSP Software Library: arm_abs_q15.c Source File Main Page Modules Data Structures Files Examples File List Globals arm_abs_q15.c Go to the documentation of this file.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_abs_q15.c 00009 * 00010 * Description: Q15 vector absolute value. 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 00054 void arm_abs_q15( 00055 q15_t * pSrc, 00056 q15_t * pDst, 00057 uint32_t blockSize) 00058 { 00059 uint32_t blkCnt; /* loop counter */ 00060 q15_t in1; /* Input value1 */ 00061 q15_t in2; /* Input value2 */ 00062 00063 00064 /*loop Unrolling */ 00065 blkCnt = blockSize >> 2u; 00066 00067 /* First part of the processing with loop unrolling. Compute 4 outputs at a time. 00068 ** a second loop below computes the remaining 1 to 3 samples. */ 00069 while(blkCnt > 0u) 00070 { 00071 /* C = |A| */ 00072 /* Read two inputs */ 00073 in1 = *pSrc++; 00074 in2 = *pSrc++; 00075 /* Store the Absolute result in the destination buffer by packing the two values, in a single cycle */ 00076 *__SIMD32(pDst)++ = 00077 __PKHBT(((in1 > 0) ? in1 : __SSAT(-in1, 16)), 00078 ((in2 > 0) ? in2 : __SSAT(-in2, 16)), 16); 00079 00080 in1 = *pSrc++; 00081 in2 = *pSrc++; 00082 *__SIMD32(pDst)++ = 00083 __PKHBT(((in1 > 0) ? in1 : __SSAT(-in1, 16)), 00084 ((in2 > 0) ? in2 : __SSAT(-in2, 16)), 16); 00085 00086 /* Decrement the loop counter */ 00087 blkCnt--; 00088 } 00089 00090 /* If the blockSize is not a multiple of 4, compute any remaining output samples here. 00091 ** No loop unrolling is used. */ 00092 blkCnt = blockSize % 0x4u; 00093 00094 while(blkCnt > 0u) 00095 { 00096 /* C = |A| */ 00097 /* Read the input */ 00098 in1 = *pSrc++; 00099 00100 /* Calculate absolute value of input and then store the result in the destination buffer. */ 00101 *pDst++ = (in1 > 0) ? in1 : __SSAT(-in1, 16); 00102 00103 /* Decrement the loop counter */ 00104 blkCnt--; 00105 } 00106 } 00107  All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Defines Generated on Mon Nov 29 2010 17:19:55 for CMSIS DSP Software Library by  1.7.2

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