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# arm_float_to_q7.c

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    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_float_to_q7.c
    00009 *
    00010 * Description:  Processing function for the Conversion from float to Q7
    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
    00061 void arm_float_to_q7(
    00062   float32_t * pSrc,
    00063   q7_t * pDst,
    00064   uint32_t blockSize)
    00065 {
    00066   float32_t *pIn = pSrc;                         /* Src pointer */
    00067   uint32_t blkCnt;                               /* loop counter */
    00068
    00069 #ifdef ARM_MATH_ROUNDING
    00070
    00071   float32_t in;
    00072
    00073 #endif
    00074
    00075   /*loop Unrolling */
    00076   blkCnt = blockSize >> 2u;
    00077
    00078   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00079    ** a second loop below computes the remaining 1 to 3 samples. */
    00080   while(blkCnt > 0u)
    00081   {
    00082 #ifdef ARM_MATH_ROUNDING
    00083     /* C = A * 128 */
    00084     /* convert from float to q7 and then store the results in the destination buffer */
    00085     in = *pIn++;
    00086     in = (in * 128);
    00087     in += in > 0 ? 0.5 : -0.5;
    00088     *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
    00089
    00090     in = *pIn++;
    00091     in = (in * 128);
    00092     in += in > 0 ? 0.5 : -0.5;
    00093     *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
    00094
    00095     in = *pIn++;
    00096     in = (in * 128);
    00097     in += in > 0 ? 0.5 : -0.5;
    00098     *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
    00099
    00100     in = *pIn++;
    00101     in = (in * 128);
    00102     in += in > 0 ? 0.5 : -0.5;
    00103     *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
    00104
    00105 #else
    00106
    00107     /* C = A * 128 */
    00108     /* convert from float to q7 and then store the results in the destination buffer */
    00109     *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
    00110     *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
    00111     *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
    00112     *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
    00113
    00114 #endif
    00115
    00116     /* Decrement the loop counter */
    00117     blkCnt--;
    00118   }
    00119
    00120   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
    00121    ** No loop unrolling is used. */
    00122   blkCnt = blockSize % 0x4u;
    00123
    00124   while(blkCnt > 0u)
    00125   {
    00126 #ifdef ARM_MATH_ROUNDING
    00127     /* C = A * 128 */
    00128     /* convert from float to q7 and then store the results in the destination buffer */
    00129     in = *pIn++;
    00130     in = (in * 128);
    00131     in += in > 0 ? 0.5 : -0.5;
    00132     *pDst++ = (q7_t) (__SSAT((q15_t) (in), 8));
    00133
    00134 #else
    00135
    00136     /* C = A * 128 */
    00137     /* convert from float to q7 and then store the results in the destination buffer */
    00138     *pDst++ = __SSAT((q31_t) (*pIn++ * 128.0f), 8);
    00139
    00140 #endif
    00141
    00142     /* Decrement the loop counter */
    00143     blkCnt--;
    00144   }
    00145 }
    00146

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