1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_dot_prod_q7.c
4 * Description: Q7 dot product
5 *
6 * $Date: 27. January 2017
7 * $Revision: V.1.5.1
8 *
9 * Target Processor: Cortex-M cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
13 *
14 * SPDX-License-Identifier: Apache-2.0
15 *
16 * Licensed under the Apache License, Version 2.0 (the License); you may
17 * not use this file except in compliance with the License.
18 * You may obtain a copy of the License at
19 *
20 * www.apache.org/licenses/LICENSE-2.0
21 *
22 * Unless required by applicable law or agreed to in writing, software
23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25 * See the License for the specific language governing permissions and
26 * limitations under the License.
27 */
28
29 #include "arm_math.h"
30
31 /**
32 * @ingroup groupMath
33 */
34
35 /**
36 * @addtogroup dot_prod
37 * @{
38 */
39
40 /**
41 * @brief Dot product of Q7 vectors.
42 * @param[in] *pSrcA points to the first input vector
43 * @param[in] *pSrcB points to the second input vector
44 * @param[in] blockSize number of samples in each vector
45 * @param[out] *result output result returned here
46 * @return none.
47 *
48 * <b>Scaling and Overflow Behavior:</b>
49 * \par
50 * The intermediate multiplications are in 1.7 x 1.7 = 2.14 format and these
51 * results are added to an accumulator in 18.14 format.
52 * Nonsaturating additions are used and there is no danger of wrap around as long as
53 * the vectors are less than 2^18 elements long.
54 * The return result is in 18.14 format.
55 */
56
arm_dot_prod_q7(q7_t * pSrcA,q7_t * pSrcB,uint32_t blockSize,q31_t * result)57 void arm_dot_prod_q7(
58 q7_t * pSrcA,
59 q7_t * pSrcB,
60 uint32_t blockSize,
61 q31_t * result)
62 {
63 uint32_t blkCnt; /* loop counter */
64
65 q31_t sum = 0; /* Temporary variables to store output */
66
67 #if defined (ARM_MATH_DSP)
68
69 /* Run the below code for Cortex-M4 and Cortex-M3 */
70
71 q31_t input1, input2; /* Temporary variables to store input */
72 q31_t inA1, inA2, inB1, inB2; /* Temporary variables to store input */
73
74
75
76 /*loop Unrolling */
77 blkCnt = blockSize >> 2u;
78
79 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
80 ** a second loop below computes the remaining 1 to 3 samples. */
81 while (blkCnt > 0u)
82 {
83 /* read 4 samples at a time from sourceA */
84 input1 = *__SIMD32(pSrcA)++;
85 /* read 4 samples at a time from sourceB */
86 input2 = *__SIMD32(pSrcB)++;
87
88 /* extract two q7_t samples to q15_t samples */
89 inA1 = __SXTB16(__ROR(input1, 8));
90 /* extract reminaing two samples */
91 inA2 = __SXTB16(input1);
92 /* extract two q7_t samples to q15_t samples */
93 inB1 = __SXTB16(__ROR(input2, 8));
94 /* extract reminaing two samples */
95 inB2 = __SXTB16(input2);
96
97 /* multiply and accumulate two samples at a time */
98 sum = __SMLAD(inA1, inB1, sum);
99 sum = __SMLAD(inA2, inB2, sum);
100
101 /* Decrement the loop counter */
102 blkCnt--;
103 }
104
105 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
106 ** No loop unrolling is used. */
107 blkCnt = blockSize % 0x4u;
108
109 while (blkCnt > 0u)
110 {
111 /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
112 /* Dot product and then store the results in a temporary buffer. */
113 sum = __SMLAD(*pSrcA++, *pSrcB++, sum);
114
115 /* Decrement the loop counter */
116 blkCnt--;
117 }
118
119 #else
120
121 /* Run the below code for Cortex-M0 */
122
123
124
125 /* Initialize blkCnt with number of samples */
126 blkCnt = blockSize;
127
128 while (blkCnt > 0u)
129 {
130 /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
131 /* Dot product and then store the results in a temporary buffer. */
132 sum += (q31_t) ((q15_t) * pSrcA++ * *pSrcB++);
133
134 /* Decrement the loop counter */
135 blkCnt--;
136 }
137
138 #endif /* #if defined (ARM_MATH_DSP) */
139
140
141 /* Store the result in the destination buffer in 18.14 format */
142 *result = sum;
143 }
144
145 /**
146 * @} end of dot_prod group
147 */
148