1 /* ----------------------------------------------------------------------
2  * Project:      CMSIS DSP Library
3  * Title:        arm_q7_to_f64.c
4  * Description:  Converts the elements of the Q7 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 q7_to_x  Convert 8-bit fixed point value
37  */
38 
39 /**
40   @addtogroup q7_to_x
41   @{
42  */
43 
44 /**
45   @brief         Converts the elements of the Q7 vector to 64 bit floating-point vector.
46   @param[in]     pSrc       points to the Q7 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] / 128;   0 <= n < blockSize.
54   </pre>
55  */
arm_q7_to_f64(const q7_t * pSrc,float64_t * pDst,uint32_t blockSize)56 void arm_q7_to_f64(
57   const q7_t * pSrc,
58         float64_t * pDst,
59         uint32_t blockSize)
60 {
61         uint32_t blkCnt;                               /* Loop counter */
62   const q7_t *pIn = pSrc;                              /* Source pointer */
63 
64 #if defined (ARM_MATH_LOOPUNROLL)
65 
66   /* Loop unrolling: Compute 4 outputs at a time */
67   blkCnt = blockSize >> 2U;
68 
69   while (blkCnt > 0U)
70   {
71     /* C = (float64_t) A / 128 */
72 
73     /* Convert from q7 to float and store result in destination buffer */
74     *pDst++ = ((float64_t) * pIn++ / 128.0);
75     *pDst++ = ((float64_t) * pIn++ / 128.0);
76     *pDst++ = ((float64_t) * pIn++ / 128.0);
77     *pDst++ = ((float64_t) * pIn++ / 128.0);
78 
79     /* Decrement loop counter */
80     blkCnt--;
81   }
82 
83   /* Loop unrolling: Compute remaining outputs */
84   blkCnt = blockSize % 0x4U;
85 
86 #else
87 
88   /* Initialize blkCnt with number of samples */
89   blkCnt = blockSize;
90 
91 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
92 
93   while (blkCnt > 0U)
94   {
95     /* C = (float64_t) A / 128 */
96 
97     /* Convert from q7 to float and store result in destination buffer */
98     *pDst++ = ((float64_t) * pIn++ / 128.0);
99 
100     /* Decrement loop counter */
101     blkCnt--;
102   }
103 
104 }
105 
106 
107 /**
108   @} end of q7_to_x group
109  */
110 
111