1 /* ----------------------------------------------------------------------
2 * Copyright (C) 2010 ARM Limited. All rights reserved.
7 * Project: CMSIS DSP Library
8 * Title: arm_dot_prod_q15.c
10 * Description: Q15 dot product.
12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
14 * Version 1.0.10 2011/7/15
15 * Big Endian support added and Merged M0 and M3/M4 Source code.
17 * Version 1.0.3 2010/11/29
18 * Re-organized the CMSIS folders and updated documentation.
20 * Version 1.0.2 2010/11/11
21 * Documentation updated.
23 * Version 1.0.1 2010/10/05
24 * Production release and review comments incorporated.
26 * Version 1.0.0 2010/09/20
27 * Production release and review comments incorporated.
29 * Version 0.0.7 2010/06/10
30 * Misra-C changes done
31 * -------------------------------------------------------------------- */
40 * @addtogroup dot_prod
45 * @brief Dot product of Q15 vectors.
46 * @param[in] *pSrcA points to the first input vector
47 * @param[in] *pSrcB points to the second input vector
48 * @param[in] blockSize number of samples in each vector
49 * @param[out] *result output result returned here
52 * <b>Scaling and Overflow Behavior:</b>
54 * The intermediate multiplications are in 1.15 x 1.15 = 2.30 format and these
55 * results are added to a 64-bit accumulator in 34.30 format.
56 * Nonsaturating additions are used and given that there are 33 guard bits in the accumulator
57 * there is no risk of overflow.
58 * The return result is in 34.30 format.
61 void arm_dot_prod_q15(
67 q63_t sum = 0; /* Temporary result storage */
68 uint32_t blkCnt; /* loop counter */
72 /* Run the below code for Cortex-M4 and Cortex-M3 */
76 blkCnt = blockSize >> 2u;
78 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
79 ** a second loop below computes the remaining 1 to 3 samples. */
82 /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
83 /* Calculate dot product and then store the result in a temporary buffer. */
84 sum = __SMLALD(*__SIMD32(pSrcA)++, *__SIMD32(pSrcB)++, sum);
85 sum = __SMLALD(*__SIMD32(pSrcA)++, *__SIMD32(pSrcB)++, sum);
87 /* Decrement the loop counter */
91 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
92 ** No loop unrolling is used. */
93 blkCnt = blockSize % 0x4u;
97 /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
98 /* Calculate dot product and then store the results in a temporary buffer. */
99 sum = __SMLALD(*pSrcA++, *pSrcB++, sum);
101 /* Decrement the loop counter */
108 /* Run the below code for Cortex-M0 */
110 /* Initialize blkCnt with number of samples */
115 /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
116 /* Calculate dot product and then store the results in a temporary buffer. */
117 sum += (q63_t) ((q31_t) * pSrcA++ * *pSrcB++);
119 /* Decrement the loop counter */
123 #endif /* #ifndef ARM_MATH_CM0 */
125 /* Store the result in the destination buffer in 34.30 format */
131 * @} end of dot_prod group