/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date: 15. February 2012
* $Revision: V1.1.0
*
* Project: CMSIS DSP Library
* Title: arm_cmplx_mult_real_q31.c
*
* Description: Q31 complex by real multiplication
*
* 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 groupCmplxMath
*/
/**
* @addtogroup CmplxByRealMult
* @{
*/
/**
* @brief Q31 complex-by-real multiplication
* @param[in] *pSrcCmplx points to the complex input vector
* @param[in] *pSrcReal points to the real input vector
* @param[out] *pCmplxDst points to the complex output vector
* @param[in] numSamples number of samples in each vector
* @return none.
*
* <b>Scaling and Overflow Behavior:</b>
* \par
* The function uses saturating arithmetic.
* Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.
*/
void arm_cmplx_mult_real_q31(
q31_t * pSrcCmplx,
q31_t * pSrcReal,
q31_t * pCmplxDst,
uint32_t numSamples)
{
q31_t inA1; /* Temporary variable to store input value */
#ifndef ARM_MATH_CM0
/* Run the below code for Cortex-M4 and Cortex-M3 */
uint32_t blkCnt; /* loop counters */
q31_t inA2, inA3, inA4; /* Temporary variables to hold input data */
q31_t inB1, inB2; /* Temporary variabels to hold input data */
q31_t out1, out2, out3, out4; /* Temporary variables to hold output data */
/* loop Unrolling */
blkCnt = numSamples >> 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[2 * i] = A[2 * i] * B[i]. */
/* C[2 * i + 1] = A[2 * i + 1] * B[i]. */
/* read real input from complex input buffer */
inA1 = *pSrcCmplx++;
inA2 = *pSrcCmplx++;
/* read input from real input bufer */
inB1 = *pSrcReal++;
inB2 = *pSrcReal++;
/* read imaginary input from complex input buffer */
inA3 = *pSrcCmplx++;
inA4 = *pSrcCmplx++;
/* multiply complex input with real input */
out1 = ((q63_t) inA1 * inB1) >> 32;
out2 = ((q63_t) inA2 * inB1) >> 32;
out3 = ((q63_t) inA3 * inB2) >> 32;
out4 = ((q63_t) inA4 * inB2) >> 32;
/* sature the result */
out1 = __SSAT(out1, 31);
out2 = __SSAT(out2, 31);
out3 = __SSAT(out3, 31);
out4 = __SSAT(out4, 31);
/* get result in 1.31 format */
out1 = out1 << 1;
out2 = out2 << 1;
out3 = out3 << 1;
out4 = out4 << 1;
/* store the result to destination buffer */
*pCmplxDst++ = out1;
*pCmplxDst++ = out2;
*pCmplxDst++ = out3;
*pCmplxDst++ = out4;
/* read real input from complex input buffer */
inA1 = *pSrcCmplx++;
inA2 = *pSrcCmplx++;
/* read input from real input bufer */
inB1 = *pSrcReal++;
inB2 = *pSrcReal++;
/* read imaginary input from complex input buffer */
inA3 = *pSrcCmplx++;
inA4 = *pSrcCmplx++;
/* multiply complex input with real input */
out1 = ((q63_t) inA1 * inB1) >> 32;
out2 = ((q63_t) inA2 * inB1) >> 32;
out3 = ((q63_t) inA3 * inB2) >> 32;
out4 = ((q63_t) inA4 * inB2) >> 32;
/* sature the result */
out1 = __SSAT(out1, 31);
out2 = __SSAT(out2, 31);
out3 = __SSAT(out3, 31);
out4 = __SSAT(out4, 31);
/* get result in 1.31 format */
out1 = out1 << 1;
out2 = out2 << 1;
out3 = out3 << 1;
out4 = out4 << 1;
/* store the result to destination buffer */
*pCmplxDst++ = out1;
*pCmplxDst++ = out2;
*pCmplxDst++ = out3;
*pCmplxDst++ = out4;
/* Decrement the numSamples loop counter */
blkCnt--;
}
/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
** No loop unrolling is used. */
blkCnt = numSamples % 0x4u;
while(blkCnt > 0u)
{
/* C[2 * i] = A[2 * i] * B[i]. */
/* C[2 * i + 1] = A[2 * i + 1] * B[i]. */
/* read real input from complex input buffer */
inA1 = *pSrcCmplx++;
inA2 = *pSrcCmplx++;
/* read input from real input bufer */
inB1 = *pSrcReal++;
/* multiply complex input with real input */
out1 = ((q63_t) inA1 * inB1) >> 32;
out2 = ((q63_t) inA2 * inB1) >> 32;
/* sature the result */
out1 = __SSAT(out1, 31);
out2 = __SSAT(out2, 31);
/* get result in 1.31 format */
out1 = out1 << 1;
out2 = out2 << 1;
/* store the result to destination buffer */
*pCmplxDst++ = out1;
*pCmplxDst++ = out2;
/* Decrement the numSamples loop counter */
blkCnt--;
}
#else
/* Run the below code for Cortex-M0 */
while(numSamples > 0u)
{
/* realOut = realA * realB. */
/* imagReal = imagA * realB. */
inA1 = *pSrcReal++;
/* store the result in the destination buffer. */
*pCmplxDst++ =
(q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
*pCmplxDst++ =
(q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
/* Decrement the numSamples loop counter */
numSamples--;
}
#endif /* #ifndef ARM_MATH_CM0 */
}
/**
* @} end of CmplxByRealMult group
*/