CMSIS DSP Software Library: arm_shift_q31.c Source File Main Page Modules Data Structures Files Examples File List Globals arm_shift_q31.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_shift_q31.c 00009 * 00010 * Description: Shifts the elements of a Q31 vector 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 00070 void arm_shift_q31( 00071 q31_t * pSrc, 00072 int8_t shiftBits, 00073 q31_t * pDst, 00074 uint32_t blockSize) 00075 { 00076 uint32_t blkCnt; /* loop counter */ 00077 uint32_t sign; /* Sign of shiftBits */ 00078 00079 00080 /*loop Unrolling */ 00081 blkCnt = blockSize >> 2u; 00082 00083 /* Getting the sign of shiftBits */ 00084 sign = (shiftBits & 0x80000000); 00085 00086 /* First part of the processing with loop unrolling. Compute 4 outputs at a time. 00087 ** a second loop below computes the remaining 1 to 3 samples. */ 00088 while(blkCnt > 0u) 00089 { 00090 /* C = A (>> or <<) shiftBits */ 00091 /* Shift the input and then store the results in the destination buffer. */ 00092 *pDst++ = (sign == 0u) ? clip_q63_to_q31((q63_t) * pSrc++ << shiftBits) : 00093 (*pSrc++ >> -shiftBits); 00094 *pDst++ = (sign == 0u) ? clip_q63_to_q31((q63_t) * pSrc++ << shiftBits) : 00095 (*pSrc++ >> -shiftBits); 00096 *pDst++ = (sign == 0u) ? clip_q63_to_q31((q63_t) * pSrc++ << shiftBits) : 00097 (*pSrc++ >> -shiftBits); 00098 *pDst++ = (sign == 0u) ? clip_q63_to_q31((q63_t) * pSrc++ << shiftBits) : 00099 (*pSrc++ >> -shiftBits); 00100 00101 /* Decrement the loop counter */ 00102 blkCnt--; 00103 } 00104 00105 /* If the blockSize is not a multiple of 4, compute any remaining output samples here. 00106 ** No loop unrolling is used. */ 00107 blkCnt = blockSize % 0x4u; 00108 00109 while(blkCnt > 0u) 00110 { 00111 /* C = A (>> or <<) shiftBits */ 00112 /* Shift the input and then store the result in the destination buffer. */ 00113 *pDst++ = (sign == 0u) ? clip_q63_to_q31((q63_t) * pSrc++ << shiftBits) : 00114 (*pSrc++ >> -shiftBits); 00115 00116 /* Decrement the loop counter */ 00117 blkCnt--; 00118 } 00119 00120 } 00121  All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Defines Generated on Mon Nov 29 2010 17:19:57 for CMSIS DSP Software Library by  1.7.2

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