1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_q15_to_f64.c
4 * Description: Converts the elements of the Q15 vector to 64 bit floating-point vector
5 *
6 * $Date: 18 August 2022
7 * $Revision: V1.0.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2022 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 "dsp/support_functions.h"
30
31 /**
32 @ingroup groupSupport
33 */
34
35 /**
36 * @defgroup q15_to_x Convert 16-bit fixed point value
37 */
38
39 /**
40 @addtogroup q15_to_x
41 @{
42 */
43
44 /**
45 @brief Converts the elements of the Q15 vector to 64 bit floating-point vector.
46 @param[in] pSrc points to the Q15 input vector
47 @param[out] pDst points to the 64 bit floating-point output vector
48 @param[in] blockSize number of samples in each vector
49
50 @par Details
51 The equation used for the conversion process is:
52 <pre>
53 pDst[n] = (float64_t) pSrc[n] / 32768; 0 <= n < blockSize.
54 </pre>
55 */
56
arm_q15_to_f64(const q15_t * pSrc,float64_t * pDst,uint32_t blockSize)57 void arm_q15_to_f64(
58 const q15_t * pSrc,
59 float64_t * pDst,
60 uint32_t blockSize)
61 {
62 uint32_t blkCnt; /* Loop counter */
63 const q15_t *pIn = pSrc; /* Source pointer */
64
65 #if defined (ARM_MATH_LOOPUNROLL)
66
67 /* Loop unrolling: Compute 4 outputs at a time */
68 blkCnt = blockSize >> 2U;
69
70 while (blkCnt > 0U)
71 {
72 /* C = (float64_t) A / 32768 */
73
74 /* Convert from q15 to float and store result in destination buffer */
75 *pDst++ = ((float64_t) * pIn++ / 32768.0);
76 *pDst++ = ((float64_t) * pIn++ / 32768.0);
77 *pDst++ = ((float64_t) * pIn++ / 32768.0);
78 *pDst++ = ((float64_t) * pIn++ / 32768.0);
79
80 /* Decrement loop counter */
81 blkCnt--;
82 }
83
84 /* Loop unrolling: Compute remaining outputs */
85 blkCnt = blockSize % 0x4U;
86
87 #else
88
89 /* Initialize blkCnt with number of samples */
90 blkCnt = blockSize;
91
92 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
93
94 while (blkCnt > 0U)
95 {
96 /* C = (float64_t) A / 32768 */
97
98 /* Convert from q15 to float and store result in destination buffer */
99 *pDst++ = ((float64_t) *pIn++ / 32768.0);
100
101 /* Decrement loop counter */
102 blkCnt--;
103 }
104
105 }
106
107
108 /**
109 @} end of q15_to_x group
110 */
111
