source: S-port/trunk/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_mult_q7.c

Last change on this file was 1, checked in by AlexLir, 3 years ago
File size: 3.4 KB
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1/* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_mult_q7.c
4 * Description: Q7 vector multiplication
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 BasicMult
37 * @{
38 */
39
40/**
41 * @brief Q7 vector multiplication
42 * @param[in] *pSrcA points to the first input vector
43 * @param[in] *pSrcB points to the second input vector
44 * @param[out] *pDst points to the output vector
45 * @param[in] blockSize number of samples in each vector
46 * @return none.
47 *
48 * <b>Scaling and Overflow Behavior:</b>
49 * \par
50 * The function uses saturating arithmetic.
51 * Results outside of the allowable Q7 range [0x80 0x7F] will be saturated.
52 */
53
54void arm_mult_q7(
55 q7_t * pSrcA,
56 q7_t * pSrcB,
57 q7_t * pDst,
58 uint32_t blockSize)
59{
60 uint32_t blkCnt; /* loop counters */
61
62#if defined (ARM_MATH_DSP)
63
64/* Run the below code for Cortex-M4 and Cortex-M3 */
65 q7_t out1, out2, out3, out4; /* Temporary variables to store the product */
66
67 /* loop Unrolling */
68 blkCnt = blockSize >> 2U;
69
70 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
71 ** a second loop below computes the remaining 1 to 3 samples. */
72 while (blkCnt > 0U)
73 {
74 /* C = A * B */
75 /* Multiply the inputs and store the results in temporary variables */
76 out1 = (q7_t) __SSAT((((q15_t) (*pSrcA++) * (*pSrcB++)) >> 7), 8);
77 out2 = (q7_t) __SSAT((((q15_t) (*pSrcA++) * (*pSrcB++)) >> 7), 8);
78 out3 = (q7_t) __SSAT((((q15_t) (*pSrcA++) * (*pSrcB++)) >> 7), 8);
79 out4 = (q7_t) __SSAT((((q15_t) (*pSrcA++) * (*pSrcB++)) >> 7), 8);
80
81 /* Store the results of 4 inputs in the destination buffer in single cycle by packing */
82 *__SIMD32(pDst)++ = __PACKq7(out1, out2, out3, out4);
83
84 /* Decrement the blockSize loop counter */
85 blkCnt--;
86 }
87
88 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
89 ** No loop unrolling is used. */
90 blkCnt = blockSize % 0x4U;
91
92#else
93
94 /* Run the below code for Cortex-M0 */
95
96 /* Initialize blkCnt with number of samples */
97 blkCnt = blockSize;
98
99#endif /* #if defined (ARM_MATH_DSP) */
100
101
102 while (blkCnt > 0U)
103 {
104 /* C = A * B */
105 /* Multiply the inputs and store the result in the destination buffer */
106 *pDst++ = (q7_t) __SSAT((((q15_t) (*pSrcA++) * (*pSrcB++)) >> 7), 8);
107
108 /* Decrement the blockSize loop counter */
109 blkCnt--;
110 }
111}
112
113/**
114 * @} end of BasicMult group
115 */
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