1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_q31_to_float.c
4 * Description: Converts the elements of the Q31 vector to floating-point vector
5 *
6 * $Date: 23 April 2021
7 * $Revision: V1.9.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2021 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 q31_to_x Convert 32-bit Integer value
37 */
38
39 /**
40 @addtogroup q31_to_x
41 @{
42 */
43
44 /**
45 @brief Converts the elements of the Q31 vector to floating-point vector.
46 @param[in] pSrc points to the Q31 input vector
47 @param[out] pDst points to the floating-point output vector
48 @param[in] blockSize number of samples in each vector
49 @return none
50
51 @par Details
52 The equation used for the conversion process is:
53 <pre>
54 pDst[n] = (float32_t) pSrc[n] / 2147483648; 0 <= n < blockSize.
55 </pre>
56 */
57 #if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
arm_q31_to_float(const q31_t * pSrc,float32_t * pDst,uint32_t blockSize)58 void arm_q31_to_float(
59 const q31_t * pSrc,
60 float32_t * pDst,
61 uint32_t blockSize)
62 {
63 uint32_t blkCnt; /* loop counters */
64 q31x4_t vecDst;
65 q31_t const *pSrcVec;
66
67 pSrcVec = (q31_t const *) pSrc;
68 blkCnt = blockSize >> 2;
69 while (blkCnt > 0U)
70 {
71 /* C = (float32_t) A / 2147483648 */
72 /* convert from q31 to float and then store the results in the destination buffer */
73 vecDst = vld1q(pSrcVec);
74 pSrcVec += 4;
75 vstrwq(pDst, vcvtq_n_f32_s32(vecDst, 31));
76 pDst += 4;
77 /*
78 * Decrement the blockSize loop counter
79 */
80 blkCnt--;
81 }
82 /*
83 * tail
84 * (will be merged thru tail predication)
85 */
86 blkCnt = blockSize & 3;
87 while (blkCnt > 0U)
88 {
89 /* C = (float32_t) A / 2147483648 */
90
91 /* Convert from q31 to float and store result in destination buffer */
92 *pDst++ = ((float32_t) *pSrcVec++ / 2147483648.0f);
93
94 /* Decrement loop counter */
95 blkCnt--;
96 }
97 }
98
99 #else
100 #if defined(ARM_MATH_NEON_EXPERIMENTAL)
arm_q31_to_float(const q31_t * pSrc,float32_t * pDst,uint32_t blockSize)101 void arm_q31_to_float(
102 const q31_t * pSrc,
103 float32_t * pDst,
104 uint32_t blockSize)
105 {
106 const q31_t *pIn = pSrc; /* Src pointer */
107 uint32_t blkCnt; /* loop counter */
108
109 int32x4_t inV;
110 float32x4_t outV;
111
112 blkCnt = blockSize >> 2U;
113
114 /* Compute 4 outputs at a time.
115 ** a second loop below computes the remaining 1 to 3 samples. */
116 while (blkCnt > 0U)
117 {
118 /* C = (float32_t) A / 2147483648 */
119 /* Convert from q31 to float and then store the results in the destination buffer */
120 inV = vld1q_s32(pIn);
121 pIn += 4;
122
123 outV = vcvtq_n_f32_s32(inV,31);
124
125 vst1q_f32(pDst, outV);
126 pDst += 4;
127
128 /* Decrement the loop counter */
129 blkCnt--;
130 }
131
132 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
133 ** No loop unrolling is used. */
134 blkCnt = blockSize & 3;
135
136
137 while (blkCnt > 0U)
138 {
139 /* C = (float32_t) A / 2147483648 */
140 /* Convert from q31 to float and then store the results in the destination buffer */
141 *pDst++ = ((float32_t) * pIn++ / 2147483648.0f);
142
143 /* Decrement the loop counter */
144 blkCnt--;
145 }
146 }
147 #else
arm_q31_to_float(const q31_t * pSrc,float32_t * pDst,uint32_t blockSize)148 void arm_q31_to_float(
149 const q31_t * pSrc,
150 float32_t * pDst,
151 uint32_t blockSize)
152 {
153 const q31_t *pIn = pSrc; /* Src pointer */
154 uint32_t blkCnt; /* loop counter */
155
156 #if defined (ARM_MATH_LOOPUNROLL)
157
158 /* Loop unrolling */
159 blkCnt = blockSize >> 2U;
160
161 while (blkCnt > 0U)
162 {
163 /* C = (float32_t) A / 2147483648 */
164
165 /* Convert from q31 to float and store result in destination buffer */
166 *pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
167 *pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
168 *pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
169 *pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
170
171 /* Decrement loop counter */
172 blkCnt--;
173 }
174
175 /* Loop unrolling: Compute remaining outputs */
176 blkCnt = blockSize % 0x4U;
177
178 #else
179
180 /* Initialize blkCnt with number of samples */
181 blkCnt = blockSize;
182
183 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
184
185 while (blkCnt > 0U)
186 {
187 /* C = (float32_t) A / 2147483648 */
188
189 /* Convert from q31 to float and store result in destination buffer */
190 *pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
191
192 /* Decrement loop counter */
193 blkCnt--;
194 }
195
196 }
197 #endif /* #if defined(ARM_MATH_NEON) */
198 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
199
200 /**
201 @} end of q31_to_x group
202 */
203