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# arm_cmplx_mult_cmplx_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_mult_cmplx_q31.c
    00009 *
    00010 * Description:  Q31 complex-by-complex multiplication
    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
    00053 void arm_cmplx_mult_cmplx_q31(
    00054   q31_t * pSrcA,
    00055   q31_t * pSrcB,
    00056   q31_t * pDst,
    00057   uint32_t numSamples)
    00058 {
    00059   q31_t a, b, c, d;                              /* Temporary variables to store real and imaginary values */
    00060   uint32_t blkCnt;                               /* loop counters */
    00061
    00062   /* loop Unrolling */
    00063   blkCnt = numSamples >> 2u;
    00064
    00065   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00066    ** a second loop below computes the remaining 1 to 3 samples. */
    00067   while(blkCnt > 0u)
    00068   {
    00069     /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
    00070     /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
    00071     a = *pSrcA++;
    00072     b = *pSrcA++;
    00073     c = *pSrcB++;
    00074     d = *pSrcB++;
    00075
    00076     /* store the real result in 3.29 format in the destination buffer. */
    00077     *pDst++ = (q31_t) ((((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33));
    00078     /* store the imag result in 3.29 format in the destination buffer. */
    00079     *pDst++ = (q31_t) ((((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33));
    00080
    00081     a = *pSrcA++;
    00082     b = *pSrcA++;
    00083     c = *pSrcB++;
    00084     d = *pSrcB++;
    00085
    00086     /* store the result in 3.29 format in the destination buffer. */
    00087     *pDst++ = (q31_t) ((((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33));
    00088     /* store the result in 3.29 format in the destination buffer. */
    00089     *pDst++ = (q31_t) ((((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33));
    00090
    00091     a = *pSrcA++;
    00092     b = *pSrcA++;
    00093     c = *pSrcB++;
    00094     d = *pSrcB++;
    00095
    00096     /* store the result in 3.29 format in the destination buffer. */
    00097     *pDst++ = (q31_t) ((((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33));
    00098     /* store the result in 3.29 format in the destination buffer. */
    00099     *pDst++ = (q31_t) ((((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33));
    00100
    00101     a = *pSrcA++;
    00102     b = *pSrcA++;
    00103     c = *pSrcB++;
    00104     d = *pSrcB++;
    00105
    00106     /* store the result in 3.29 format in the destination buffer. */
    00107     *pDst++ = (q31_t) ((((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33));
    00108     /* store the result in 3.29 format in the destination buffer. */
    00109     *pDst++ = (q31_t) ((((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33));
    00110
    00111     /* Decrement the blockSize loop counter */
    00112     blkCnt--;
    00113   }
    00114
    00115   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
    00116    ** No loop unrolling is used. */
    00117   blkCnt = numSamples % 0x4u;
    00118
    00119   while(blkCnt > 0u)
    00120   {
    00121     /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
    00122     /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
    00123     a = *pSrcA++;
    00124     b = *pSrcA++;
    00125     c = *pSrcB++;
    00126     d = *pSrcB++;
    00127
    00128     /* store the result in 3.29 format in the destination buffer. */
    00129     *pDst++ = (q31_t) ((((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33));
    00130     /* store the result in 3.29 format in the destination buffer. */
    00131     *pDst++ = (q31_t) ((((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33));
    00132
    00133     /* Decrement the blockSize loop counter */
    00134     blkCnt--;
    00135   }
    00136 }
    00137

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