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# arm_cmplx_mag_squared_q31.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_cmplx_mag_squared_q31.c
    00009 *
    00010 * Description:  Q31 complex magnitude squared.
    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
    00052 void arm_cmplx_mag_squared_q31(
    00053   q31_t * pSrc,
    00054   q31_t * pDst,
    00055   uint32_t numSamples)
    00056 {
    00057   q31_t real, imag;                              /* Temporary variables to store real and imaginary values */
    00058   q31_t acc0, acc1;                              /* Accumulators */
    00059   uint32_t blkCnt;                               /* loop counter */
    00060
    00061   /* loop Unrolling */
    00062   blkCnt = numSamples >> 2u;
    00063
    00064   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00065    ** a second loop below computes the remaining 1 to 3 samples. */
    00066   while(blkCnt > 0u)
    00067   {
    00068     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
    00069     real = *pSrc++;
    00070     imag = *pSrc++;
    00071     acc0 = (q31_t) (((q63_t) real * real) >> 33);
    00072     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
    00073     /* store the result in 3.29 format in the destination buffer. */
    00074     *pDst++ = acc0 + acc1;
    00075
    00076     real = *pSrc++;
    00077     imag = *pSrc++;
    00078     acc0 = (q31_t) (((q63_t) real * real) >> 33);
    00079     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
    00080     /* store the result in 3.29 format in the destination buffer. */
    00081     *pDst++ = acc0 + acc1;
    00082
    00083     real = *pSrc++;
    00084     imag = *pSrc++;
    00085     acc0 = (q31_t) (((q63_t) real * real) >> 33);
    00086     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
    00087     /* store the result in 3.29 format in the destination buffer. */
    00088     *pDst++ = acc0 + acc1;
    00089
    00090     real = *pSrc++;
    00091     imag = *pSrc++;
    00092     acc0 = (q31_t) (((q63_t) real * real) >> 33);
    00093     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
    00094     /* store the result in 3.29 format in the destination buffer. */
    00095     *pDst++ = acc0 + acc1;
    00096
    00097     /* Decrement the loop counter */
    00098     blkCnt--;
    00099   }
    00100
    00101   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
    00102    ** No loop unrolling is used. */
    00103   blkCnt = numSamples % 0x4u;
    00104
    00105   while(blkCnt > 0u)
    00106   {
    00107     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
    00108     real = *pSrc++;
    00109     imag = *pSrc++;
    00110     acc0 = (q31_t) (((q63_t) real * real) >> 33);
    00111     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
    00112     /* store the result in 3.29 format in the destination buffer. */
    00113     *pDst++ = acc0 + acc1;
    00114
    00115     /* Decrement the loop counter */
    00116     blkCnt--;
    00117   }
    00118 }
    00119

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