CMSIS DSP Software Library: arm_q15_to_float.c Source File

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# arm_q15_to_float.c

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    00001 /* ----------------------------------------------------------------------------
    00002 * Copyright (C) 2010 ARM Limited. All rights reserved.
    00003 *
    00004 * $Date:        15. July 2011
    00005 * $Revision:    V1.0.10
    00006 *
    00007 * Project:      CMSIS DSP Library
    00008 * Title:        arm_q15_to_float.c
    00009 *
    00010 * Description:  Converts the elements of the Q15 vector to floating-point vector.
    00011 *
    00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
    00013 *
    00014 * Version 1.0.10 2011/7/15
    00015 *    Big Endian support added and Merged M0 and M3/M4 Source code.
    00016 *
    00017 * Version 1.0.3 2010/11/29
    00018 *    Re-organized the CMSIS folders and updated documentation.
    00019 *
    00020 * Version 1.0.2 2010/11/11
    00021 *    Documentation updated.
    00022 *
    00023 * Version 1.0.1 2010/10/05
    00024 *    Production release and review comments incorporated.
    00025 *
    00026 * Version 1.0.0 2010/09/20
    00027 *    Production release and review comments incorporated.
    00028 * ---------------------------------------------------------------------------- */
    00029
    00030 #include "arm_math.h"
    00031
    00066 void arm_q15_to_float(
    00067   q15_t * pSrc,
    00068   float32_t * pDst,
    00069   uint32_t blockSize)
    00070 {
    00071   q15_t *pIn = pSrc;                             /* Src pointer */
    00072   uint32_t blkCnt;                               /* loop counter */
    00073
    00074
    00075 #ifndef ARM_MATH_CM0
    00076
    00077   /* Run the below code for Cortex-M4 and Cortex-M3 */
    00078
    00079   /*loop Unrolling */
    00080   blkCnt = blockSize >> 2u;
    00081
    00082   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00083    ** a second loop below computes the remaining 1 to 3 samples. */
    00084   while(blkCnt > 0u)
    00085   {
    00086     /* C = (float32_t) A / 32768 */
    00087     /* convert from q15 to float and then store the results in the destination buffer */
    00088     *pDst++ = ((float32_t) * pIn++ / 32768.0f);
    00089     *pDst++ = ((float32_t) * pIn++ / 32768.0f);
    00090     *pDst++ = ((float32_t) * pIn++ / 32768.0f);
    00091     *pDst++ = ((float32_t) * pIn++ / 32768.0f);
    00092
    00093     /* Decrement the loop counter */
    00094     blkCnt--;
    00095   }
    00096
    00097   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
    00098    ** No loop unrolling is used. */
    00099   blkCnt = blockSize % 0x4u;
    00100
    00101 #else
    00102
    00103   /* Run the below code for Cortex-M0 */
    00104
    00105   /* Loop over blockSize number of values */
    00106   blkCnt = blockSize;
    00107
    00108 #endif /* #ifndef ARM_MATH_CM0 */
    00109
    00110   while(blkCnt > 0u)
    00111   {
    00112     /* C = (float32_t) A / 32768 */
    00113     /* convert from q15 to float and then store the results in the destination buffer */
    00114     *pDst++ = ((float32_t) * pIn++ / 32768.0f);
    00115
    00116     /* Decrement the loop counter */
    00117     blkCnt--;
    00118   }
    00119 }
    00120

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