arm_q7_to_q15.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_q7_to_q15.c  
00009 *  
00010 * Description:  Processing function for the Conversion from Q7 to Q15  
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  
00027 #include "arm_math.h" 
00028  
00029 /**  
00030  * @ingroup groupSupport  
00031  */ 
00032  
00033 /**  
00034  * @addtogroup q7_to_x  
00035  * @{  
00036  */ 
00037  
00038  
00039  
00040  
00041 /**  
00042  * @brief Converts the elements of the Q7 vector to Q15 vector.  
00043  * @param[in]       *pSrc points to the Q7 input vector  
00044  * @param[out]      *pDst points to the Q15 output vector 
00045  * @param[in]       blockSize length of the input vector  
00046  * @return none.  
00047  *  
00048  * \par Description:  
00049  *  
00050  * The equation used for the conversion process is:  
00051  * 
00052  * <pre>  
00053  *  pDst[n] = (q15_t) pSrc[n] << 8;   0 <= n < blockSize.  
00054  * </pre>  
00055  * 
00056  */ 
00057  
00058  
00059 void arm_q7_to_q15( 
00060   q7_t * pSrc, 
00061   q15_t * pDst, 
00062   uint32_t blockSize) 
00063 { 
00064   q7_t *pIn = pSrc;                              /* Src pointer */ 
00065   uint32_t blkCnt;                               /* loop counter */ 
00066  
00067   /*loop Unrolling */ 
00068   blkCnt = blockSize >> 2u; 
00069  
00070   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.  
00071    ** a second loop below computes the remaining 1 to 3 samples. */ 
00072   while(blkCnt > 0u) 
00073   { 
00074     /* C = (q15_t) A << 8 */ 
00075     /* convert from q7 to q15 and then store the results in the destination buffer */ 
00076     *pDst++ = (q15_t) * pIn++ << 8; 
00077     *pDst++ = (q15_t) * pIn++ << 8; 
00078     *pDst++ = (q15_t) * pIn++ << 8; 
00079     *pDst++ = (q15_t) * pIn++ << 8; 
00080  
00081     /* Decrement the loop counter */ 
00082     blkCnt--; 
00083   } 
00084  
00085   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.  
00086    ** No loop unrolling is used. */ 
00087   blkCnt = blockSize % 0x4u; 
00088  
00089   while(blkCnt > 0u) 
00090   { 
00091     /* C = (q15_t) A << 8 */ 
00092     /* convert from q7 to q15 and then store the results in the destination buffer */ 
00093     *pDst++ = (q15_t) * pIn++ << 8; 
00094  
00095     /* Decrement the loop counter */ 
00096     blkCnt--; 
00097   } 
00098  
00099 } 
00100  
00101 /**  
00102  * @} end of q7_to_x group  
00103  */