1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_q15_to_float.c
4 * Description: Converts the elements of the Q15 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 q15_to_x Convert 16-bit Integer value
37 */
38
39 /**
40 @addtogroup q15_to_x
41 @{
42 */
43
44 /**
45 @brief Converts the elements of the Q15 vector to floating-point vector.
46 @param[in] pSrc points to the Q15 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] / 32768; 0 <= n < blockSize.
55 </pre>
56 */
57
58 #if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
arm_q15_to_float(const q15_t * pSrc,float32_t * pDst,uint32_t blockSize)59 void arm_q15_to_float(
60 const q15_t * pSrc,
61 float32_t * pDst,
62 uint32_t blockSize)
63 {
64 uint32_t blkCnt;
65
66 q15x8_t vecDst;
67 q15_t const *pSrcVec;
68
69 pSrcVec = (q15_t const *) pSrc;
70 blkCnt = blockSize >> 2;
71 while (blkCnt > 0U)
72 {
73 /* C = (float32_t) A / 32768 */
74 /* convert from q15 to float and then store the results in the destination buffer */
75 vecDst = vldrhq_s32(pSrcVec);
76 pSrcVec += 4;
77 vstrwq(pDst, vcvtq_n_f32_s32(vecDst, 15));
78 pDst += 4;
79 /*
80 * Decrement the blockSize loop counter
81 */
82 blkCnt--;
83 }
84
85 blkCnt = blockSize & 3;
86 while (blkCnt > 0U)
87 {
88 /* C = (float32_t) A / 32768 */
89
90 /* Convert from q15 to float and store result in destination buffer */
91 *pDst++ = ((float32_t) *pSrcVec++ / 32768.0f);
92
93 /* Decrement loop counter */
94 blkCnt--;
95 }
96 }
97 #else
98 #if defined(ARM_MATH_NEON_EXPERIMENTAL)
arm_q15_to_float(const q15_t * pSrc,float32_t * pDst,uint32_t blockSize)99 void arm_q15_to_float(
100 const q15_t * pSrc,
101 float32_t * pDst,
102 uint32_t blockSize)
103 {
104 const q15_t *pIn = pSrc; /* Src pointer */
105 uint32_t blkCnt; /* loop counter */
106
107 int16x8_t inV;
108 int32x4_t inV0, inV1;
109 float32x4_t outV;
110
111 blkCnt = blockSize >> 3U;
112
113 /* Compute 8 outputs at a time.
114 ** a second loop below computes the remaining 1 to 7 samples. */
115 while (blkCnt > 0U)
116 {
117 /* C = (float32_t) A / 32768 */
118 /* convert from q15 to float and then store the results in the destination buffer */
119 inV = vld1q_s16(pIn);
120 pIn += 8;
121
122 inV0 = vmovl_s16(vget_low_s16(inV));
123 inV1 = vmovl_s16(vget_high_s16(inV));
124
125 outV = vcvtq_n_f32_s32(inV0,15);
126 vst1q_f32(pDst, outV);
127 pDst += 4;
128
129 outV = vcvtq_n_f32_s32(inV1,15);
130 vst1q_f32(pDst, outV);
131 pDst += 4;
132
133 /* Decrement the loop counter */
134 blkCnt--;
135 }
136
137 /* If the blockSize is not a multiple of 8, compute any remaining output samples here.
138 ** No loop unrolling is used. */
139 blkCnt = blockSize & 7;
140
141
142 while (blkCnt > 0U)
143 {
144 /* C = (float32_t) A / 32768 */
145 /* convert from q15 to float and then store the results in the destination buffer */
146 *pDst++ = ((float32_t) * pIn++ / 32768.0f);
147
148 /* Decrement the loop counter */
149 blkCnt--;
150 }
151 }
152 #else
arm_q15_to_float(const q15_t * pSrc,float32_t * pDst,uint32_t blockSize)153 void arm_q15_to_float(
154 const q15_t * pSrc,
155 float32_t * pDst,
156 uint32_t blockSize)
157 {
158 uint32_t blkCnt; /* Loop counter */
159 const q15_t *pIn = pSrc; /* Source pointer */
160
161 #if defined (ARM_MATH_LOOPUNROLL)
162
163 /* Loop unrolling: Compute 4 outputs at a time */
164 blkCnt = blockSize >> 2U;
165
166 while (blkCnt > 0U)
167 {
168 /* C = (float32_t) A / 32768 */
169
170 /* Convert from q15 to float and store result in destination buffer */
171 *pDst++ = ((float32_t) * pIn++ / 32768.0f);
172 *pDst++ = ((float32_t) * pIn++ / 32768.0f);
173 *pDst++ = ((float32_t) * pIn++ / 32768.0f);
174 *pDst++ = ((float32_t) * pIn++ / 32768.0f);
175
176 /* Decrement loop counter */
177 blkCnt--;
178 }
179
180 /* Loop unrolling: Compute remaining outputs */
181 blkCnt = blockSize % 0x4U;
182
183 #else
184
185 /* Initialize blkCnt with number of samples */
186 blkCnt = blockSize;
187
188 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
189
190 while (blkCnt > 0U)
191 {
192 /* C = (float32_t) A / 32768 */
193
194 /* Convert from q15 to float and store result in destination buffer */
195 *pDst++ = ((float32_t) *pIn++ / 32768.0f);
196
197 /* Decrement loop counter */
198 blkCnt--;
199 }
200
201 }
202 #endif /* #if defined(ARM_MATH_NEON) */
203 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
204
205 /**
206 @} end of q15_to_x group
207 */
208
