source: S-port/trunk/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_mult_q31.c

Last change on this file was 1, checked in by AlexLir, 3 years ago
File size: 4.1 KB
Line 
1/* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_mult_q31.c
4 * Description: Q31 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 Q31 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 Q31 range[0x80000000 0x7FFFFFFF] will be saturated.
52 */
53
54void arm_mult_q31(
55 q31_t * pSrcA,
56 q31_t * pSrcB,
57 q31_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 q31_t inA1, inA2, inA3, inA4; /* temporary input variables */
66 q31_t inB1, inB2, inB3, inB4; /* temporary input variables */
67 q31_t out1, out2, out3, out4; /* temporary output variables */
68
69 /* loop Unrolling */
70 blkCnt = blockSize >> 2U;
71
72 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
73 ** a second loop below computes the remaining 1 to 3 samples. */
74 while (blkCnt > 0U)
75 {
76 /* C = A * B */
77 /* Multiply the inputs and then store the results in the destination buffer. */
78 inA1 = *pSrcA++;
79 inA2 = *pSrcA++;
80 inA3 = *pSrcA++;
81 inA4 = *pSrcA++;
82 inB1 = *pSrcB++;
83 inB2 = *pSrcB++;
84 inB3 = *pSrcB++;
85 inB4 = *pSrcB++;
86
87 out1 = ((q63_t) inA1 * inB1) >> 32;
88 out2 = ((q63_t) inA2 * inB2) >> 32;
89 out3 = ((q63_t) inA3 * inB3) >> 32;
90 out4 = ((q63_t) inA4 * inB4) >> 32;
91
92 out1 = __SSAT(out1, 31);
93 out2 = __SSAT(out2, 31);
94 out3 = __SSAT(out3, 31);
95 out4 = __SSAT(out4, 31);
96
97 *pDst++ = out1 << 1U;
98 *pDst++ = out2 << 1U;
99 *pDst++ = out3 << 1U;
100 *pDst++ = out4 << 1U;
101
102 /* Decrement the blockSize loop counter */
103 blkCnt--;
104 }
105
106 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
107 ** No loop unrolling is used. */
108 blkCnt = blockSize % 0x4U;
109
110 while (blkCnt > 0U)
111 {
112 /* C = A * B */
113 /* Multiply the inputs and then store the results in the destination buffer. */
114 inA1 = *pSrcA++;
115 inB1 = *pSrcB++;
116 out1 = ((q63_t) inA1 * inB1) >> 32;
117 out1 = __SSAT(out1, 31);
118 *pDst++ = out1 << 1U;
119
120 /* Decrement the blockSize loop counter */
121 blkCnt--;
122 }
123
124#else
125
126 /* Run the below code for Cortex-M0 */
127
128 /* Initialize blkCnt with number of samples */
129 blkCnt = blockSize;
130
131
132 while (blkCnt > 0U)
133 {
134 /* C = A * B */
135 /* Multiply the inputs and then store the results in the destination buffer. */
136 *pDst++ =
137 (q31_t) clip_q63_to_q31(((q63_t) (*pSrcA++) * (*pSrcB++)) >> 31);
138
139 /* Decrement the blockSize loop counter */
140 blkCnt--;
141 }
142
143#endif /* #if defined (ARM_MATH_DSP) */
144}
145
146/**
147 * @} end of BasicMult group
148 */
Note: See TracBrowser for help on using the repository browser.