/* ---------------------------------------------------------------------------- * Copyright (C) 2010 ARM Limited. All rights reserved. * * $Date: 15. February 2012 * $Revision: V1.1.0 * * Project: CMSIS DSP Library * Title: arm_q7_to_float.c * * Description: Converts the elements of the Q7 vector to floating-point vector. * * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 * * Version 1.1.0 2012/02/15 * Updated with more optimizations, bug fixes and minor API changes. * * Version 1.0.10 2011/7/15 * Big Endian support added and Merged M0 and M3/M4 Source code. * * Version 1.0.3 2010/11/29 * Re-organized the CMSIS folders and updated documentation. * * Version 1.0.2 2010/11/11 * Documentation updated. * * Version 1.0.1 2010/10/05 * Production release and review comments incorporated. * * Version 1.0.0 2010/09/20 * Production release and review comments incorporated. * ---------------------------------------------------------------------------- */ #include "arm_math.h" /** * @ingroup groupSupport */ /** * @defgroup q7_to_x Convert 8-bit Integer value */ /** * @addtogroup q7_to_x * @{ */ /** * @brief Converts the elements of the Q7 vector to floating-point vector. * @param[in] *pSrc points to the Q7 input vector * @param[out] *pDst points to the floating-point output vector * @param[in] blockSize length of the input vector * @return none. * * \par Description: * * The equation used for the conversion process is: * *
    
 * 	pDst[n] = (float32_t) pSrc[n] / 128;   0 <= n < blockSize.    
 * 
* */ void arm_q7_to_float( q7_t * pSrc, float32_t * pDst, uint32_t blockSize) { q7_t *pIn = pSrc; /* Src pointer */ uint32_t blkCnt; /* loop counter */ #ifndef ARM_MATH_CM0 /* Run the below code for Cortex-M4 and Cortex-M3 */ /*loop Unrolling */ blkCnt = blockSize >> 2u; /* First part of the processing with loop unrolling. Compute 4 outputs at a time. ** a second loop below computes the remaining 1 to 3 samples. */ while(blkCnt > 0u) { /* C = (float32_t) A / 128 */ /* convert from q7 to float and then store the results in the destination buffer */ *pDst++ = ((float32_t) * pIn++ / 128.0f); *pDst++ = ((float32_t) * pIn++ / 128.0f); *pDst++ = ((float32_t) * pIn++ / 128.0f); *pDst++ = ((float32_t) * pIn++ / 128.0f); /* Decrement the loop counter */ blkCnt--; } /* If the blockSize is not a multiple of 4, compute any remaining output samples here. ** No loop unrolling is used. */ blkCnt = blockSize % 0x4u; #else /* Run the below code for Cortex-M0 */ /* Loop over blockSize number of values */ blkCnt = blockSize; #endif /* #ifndef ARM_MATH_CM0 */ while(blkCnt > 0u) { /* C = (float32_t) A / 128 */ /* convert from q7 to float and then store the results in the destination buffer */ *pDst++ = ((float32_t) * pIn++ / 128.0f); /* Decrement the loop counter */ blkCnt--; } } /** * @} end of q7_to_x group */