| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_cmplx_mult_cmplx_q31.c |
| * Description: Q31 complex-by-complex multiplication |
| * |
| * $Date: 18. March 2019 |
| * $Revision: V1.6.0 |
| * |
| * Target Processor: Cortex-M cores |
| * -------------------------------------------------------------------- */ |
| /* |
| * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * Licensed under the Apache License, Version 2.0 (the License); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an AS IS BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "arm_math.h" |
| |
| /** |
| @ingroup groupCmplxMath |
| */ |
| |
| /** |
| @addtogroup CmplxByCmplxMult |
| @{ |
| */ |
| |
| /** |
| @brief Q31 complex-by-complex multiplication. |
| @param[in] pSrcA points to first input vector |
| @param[in] pSrcB points to second input vector |
| @param[out] pDst points to output vector |
| @param[in] numSamples number of samples in each vector |
| @return none |
| |
| @par Scaling and Overflow Behavior |
| The function implements 1.31 by 1.31 multiplications and finally output is converted into 3.29 format. |
| Input down scaling is not required. |
| */ |
| |
| void arm_cmplx_mult_cmplx_q31( |
| const q31_t * pSrcA, |
| const q31_t * pSrcB, |
| q31_t * pDst, |
| uint32_t numSamples) |
| { |
| uint32_t blkCnt; /* Loop counter */ |
| q31_t a, b, c, d; /* Temporary variables */ |
| |
| #if defined (ARM_MATH_LOOPUNROLL) |
| |
| /* Loop unrolling: Compute 4 outputs at a time */ |
| blkCnt = numSamples >> 2U; |
| |
| while (blkCnt > 0U) |
| { |
| /* C[2 * i ] = A[2 * i] * B[2 * i ] - A[2 * i + 1] * B[2 * i + 1]. */ |
| /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i ]. */ |
| |
| a = *pSrcA++; |
| b = *pSrcA++; |
| c = *pSrcB++; |
| d = *pSrcB++; |
| /* store result in 3.29 format in destination buffer. */ |
| *pDst++ = (q31_t) ( (((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33) ); |
| *pDst++ = (q31_t) ( (((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33) ); |
| |
| a = *pSrcA++; |
| b = *pSrcA++; |
| c = *pSrcB++; |
| d = *pSrcB++; |
| *pDst++ = (q31_t) ( (((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33) ); |
| *pDst++ = (q31_t) ( (((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33) ); |
| |
| a = *pSrcA++; |
| b = *pSrcA++; |
| c = *pSrcB++; |
| d = *pSrcB++; |
| *pDst++ = (q31_t) ( (((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33) ); |
| *pDst++ = (q31_t) ( (((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33) ); |
| |
| a = *pSrcA++; |
| b = *pSrcA++; |
| c = *pSrcB++; |
| d = *pSrcB++; |
| *pDst++ = (q31_t) ( (((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33) ); |
| *pDst++ = (q31_t) ( (((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33) ); |
| |
| /* Decrement loop counter */ |
| blkCnt--; |
| } |
| |
| /* Loop unrolling: Compute remaining outputs */ |
| blkCnt = numSamples % 0x4U; |
| |
| #else |
| |
| /* Initialize blkCnt with number of samples */ |
| blkCnt = numSamples; |
| |
| #endif /* #if defined (ARM_MATH_LOOPUNROLL) */ |
| |
| while (blkCnt > 0U) |
| { |
| /* C[2 * i ] = A[2 * i] * B[2 * i ] - A[2 * i + 1] * B[2 * i + 1]. */ |
| /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i ]. */ |
| |
| a = *pSrcA++; |
| b = *pSrcA++; |
| c = *pSrcB++; |
| d = *pSrcB++; |
| |
| /* store result in 3.29 format in destination buffer. */ |
| *pDst++ = (q31_t) ( (((q63_t) a * c) >> 33) - (((q63_t) b * d) >> 33) ); |
| *pDst++ = (q31_t) ( (((q63_t) a * d) >> 33) + (((q63_t) b * c) >> 33) ); |
| |
| /* Decrement loop counter */ |
| blkCnt--; |
| } |
| |
| } |
| |
| /** |
| @} end of CmplxByCmplxMult group |
| */ |