1 /* ----------------------------------------------------------------------
2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
4 * $Date: 17. January 2013
7 * Project: CMSIS DSP Library
8 * Title: arm_cmplx_mult_cmplx_f32.c
10 * Description: Floating-point complex-by-complex multiplication
12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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43 * @ingroup groupCmplxMath
47 * @defgroup CmplxByCmplxMult Complex-by-Complex Multiplication
49 * Multiplies a complex vector by another complex vector and generates a complex result.
50 * The data in the complex arrays is stored in an interleaved fashion
51 * (real, imag, real, imag, ...).
52 * The parameter <code>numSamples</code> represents the number of complex
53 * samples processed. The complex arrays have a total of <code>2*numSamples</code>
56 * The underlying algorithm is used:
59 * for(n=0; n<numSamples; n++) {
60 * pDst[(2*n)+0] = pSrcA[(2*n)+0] * pSrcB[(2*n)+0] - pSrcA[(2*n)+1] * pSrcB[(2*n)+1];
61 * pDst[(2*n)+1] = pSrcA[(2*n)+0] * pSrcB[(2*n)+1] + pSrcA[(2*n)+1] * pSrcB[(2*n)+0];
65 * There are separate functions for floating-point, Q15, and Q31 data types.
69 * @addtogroup CmplxByCmplxMult
75 * @brief Floating-point complex-by-complex multiplication
76 * @param[in] *pSrcA points to the first input vector
77 * @param[in] *pSrcB points to the second input vector
78 * @param[out] *pDst points to the output vector
79 * @param[in] numSamples number of complex samples in each vector
83 void arm_cmplx_mult_cmplx_f32(
89 float32_t a1, b1, c1, d1; /* Temporary variables to store real and imaginary values */
90 uint32_t blkCnt; /* loop counters */
92 #ifndef ARM_MATH_CM0_FAMILY
94 /* Run the below code for Cortex-M4 and Cortex-M3 */
95 float32_t a2, b2, c2, d2; /* Temporary variables to store real and imaginary values */
96 float32_t acc1, acc2, acc3, acc4;
100 blkCnt = numSamples >> 2u;
102 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
103 ** a second loop below computes the remaining 1 to 3 samples. */
106 /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1]. */
107 /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i]. */
108 a1 = *pSrcA; /* A[2 * i] */
109 c1 = *pSrcB; /* B[2 * i] */
111 b1 = *(pSrcA + 1); /* A[2 * i + 1] */
112 acc1 = a1 * c1; /* acc1 = A[2 * i] * B[2 * i] */
114 a2 = *(pSrcA + 2); /* A[2 * i + 2] */
115 acc2 = (b1 * c1); /* acc2 = A[2 * i + 1] * B[2 * i] */
117 d1 = *(pSrcB + 1); /* B[2 * i + 1] */
118 c2 = *(pSrcB + 2); /* B[2 * i + 2] */
119 acc1 -= b1 * d1; /* acc1 = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1] */
121 d2 = *(pSrcB + 3); /* B[2 * i + 3] */
122 acc3 = a2 * c2; /* acc3 = A[2 * i + 2] * B[2 * i + 2] */
124 b2 = *(pSrcA + 3); /* A[2 * i + 3] */
125 acc2 += (a1 * d1); /* acc2 = A[2 * i + 1] * B[2 * i] + A[2 * i] * B[2 * i + 1] */
127 a1 = *(pSrcA + 4); /* A[2 * i + 4] */
128 acc4 = (a2 * d2); /* acc4 = A[2 * i + 2] * B[2 * i + 3] */
130 c1 = *(pSrcB + 4); /* B[2 * i + 4] */
131 acc3 -= (b2 * d2); /* acc3 = A[2 * i + 2] * B[2 * i + 2] - A[2 * i + 3] * B[2 * i + 3] */
132 *pDst = acc1; /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1] */
134 b1 = *(pSrcA + 5); /* A[2 * i + 5] */
135 acc4 += b2 * c2; /* acc4 = A[2 * i + 2] * B[2 * i + 3] + A[2 * i + 3] * B[2 * i + 2] */
137 *(pDst + 1) = acc2; /* C[2 * i + 1] = A[2 * i + 1] * B[2 * i] + A[2 * i] * B[2 * i + 1] */
172 /* Decrement the numSamples loop counter */
176 /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
177 ** No loop unrolling is used. */
178 blkCnt = numSamples % 0x4u;
182 /* Run the below code for Cortex-M0 */
185 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
189 /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1]. */
190 /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i]. */
196 /* store the result in the destination buffer. */
197 *pDst++ = (a1 * c1) - (b1 * d1);
198 *pDst++ = (a1 * d1) + (b1 * c1);
200 /* Decrement the numSamples loop counter */
206 * @} end of CmplxByCmplxMult group