1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_q7_to_float.c
4 * Description: Converts the elements of the Q7 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 q7_to_x Convert 8-bit Integer value
37 */
38
39 /**
40 @addtogroup q7_to_x
41 @{
42 */
43
44 /**
45 @brief Converts the elements of the Q7 vector to floating-point vector.
46 @param[in] pSrc points to the Q7 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] / 128; 0 <= n < blockSize.
55 </pre>
56 */
57 #if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
arm_q7_to_float(const q7_t * pSrc,float32_t * pDst,uint32_t blockSize)58 void arm_q7_to_float(
59 const q7_t * pSrc,
60 float32_t * pDst,
61 uint32_t blockSize)
62 {
63 uint32_t blkCnt; /* loop counters */
64 q7x16_t vecDst;
65 q7_t const *pSrcVec;
66
67 pSrcVec = (q7_t const *) pSrc;
68 blkCnt = blockSize >> 2;
69 while (blkCnt > 0U)
70 {
71 /* C = (float32_t) A / 32768 */
72 /* convert from q7 to float and then store the results in the destination buffer */
73 vecDst = vldrbq_s32(pSrcVec);
74 pSrcVec += 4;
75 vstrwq(pDst, vcvtq_n_f32_s32(vecDst, 7));
76 pDst += 4;
77 /*
78 * Decrement the blockSize loop counter
79 */
80 blkCnt--;
81 }
82
83 blkCnt = blockSize & 3;
84 while (blkCnt > 0U)
85 {
86 /* C = (float32_t) A / 128 */
87
88 /* Convert from q7 to float and store result in destination buffer */
89 *pDst++ = ((float32_t) * pSrcVec++ / 128.0f);
90
91 /* Decrement loop counter */
92 blkCnt--;
93 }
94 }
95 #else
96 #if defined(ARM_MATH_NEON)
arm_q7_to_float(const q7_t * pSrc,float32_t * pDst,uint32_t blockSize)97 void arm_q7_to_float(
98 const q7_t * pSrc,
99 float32_t * pDst,
100 uint32_t blockSize)
101 {
102 const q7_t *pIn = pSrc; /* Src pointer */
103 uint32_t blkCnt; /* loop counter */
104
105 int8x16_t inV;
106 int16x8_t inVLO, inVHI;
107 int32x4_t inVLL, inVLH, inVHL, inVHH;
108 float32x4_t outV;
109
110 blkCnt = blockSize >> 4U;
111
112 /* Compute 16 outputs at a time.
113 ** a second loop below computes the remaining 1 to 15 samples. */
114 while (blkCnt > 0U)
115 {
116 /* C = (float32_t) A / 128 */
117 /* Convert from q7 to float and then store the results in the destination buffer */
118 inV = vld1q_s8(pIn);
119 pIn += 16;
120
121 inVLO = vmovl_s8(vget_low_s8(inV));
122 inVHI = vmovl_s8(vget_high_s8(inV));
123
124 inVLL = vmovl_s16(vget_low_s16(inVLO));
125 inVLH = vmovl_s16(vget_high_s16(inVLO));
126 inVHL = vmovl_s16(vget_low_s16(inVHI));
127 inVHH = vmovl_s16(vget_high_s16(inVHI));
128
129 outV = vcvtq_n_f32_s32(inVLL,7);
130 vst1q_f32(pDst, outV);
131 pDst += 4;
132
133 outV = vcvtq_n_f32_s32(inVLH,7);
134 vst1q_f32(pDst, outV);
135 pDst += 4;
136
137 outV = vcvtq_n_f32_s32(inVHL,7);
138 vst1q_f32(pDst, outV);
139 pDst += 4;
140
141 outV = vcvtq_n_f32_s32(inVHH,7);
142 vst1q_f32(pDst, outV);
143 pDst += 4;
144
145 /* Decrement the loop counter */
146 blkCnt--;
147 }
148
149 /* If the blockSize is not a multiple of 16, compute any remaining output samples here.
150 ** No loop unrolling is used. */
151 blkCnt = blockSize & 0xF;
152
153 while (blkCnt > 0U)
154 {
155 /* C = (float32_t) A / 128 */
156 /* Convert from q7 to float and then store the results in the destination buffer */
157 *pDst++ = ((float32_t) * pIn++ / 128.0f);
158
159 /* Decrement the loop counter */
160 blkCnt--;
161 }
162 }
163 #else
arm_q7_to_float(const q7_t * pSrc,float32_t * pDst,uint32_t blockSize)164 void arm_q7_to_float(
165 const q7_t * pSrc,
166 float32_t * pDst,
167 uint32_t blockSize)
168 {
169 uint32_t blkCnt; /* Loop counter */
170 const q7_t *pIn = pSrc; /* Source pointer */
171
172 #if defined (ARM_MATH_LOOPUNROLL)
173
174 /* Loop unrolling: Compute 4 outputs at a time */
175 blkCnt = blockSize >> 2U;
176
177 while (blkCnt > 0U)
178 {
179 /* C = (float32_t) A / 128 */
180
181 /* Convert from q7 to float and store result in destination buffer */
182 *pDst++ = ((float32_t) * pIn++ / 128.0f);
183 *pDst++ = ((float32_t) * pIn++ / 128.0f);
184 *pDst++ = ((float32_t) * pIn++ / 128.0f);
185 *pDst++ = ((float32_t) * pIn++ / 128.0f);
186
187 /* Decrement loop counter */
188 blkCnt--;
189 }
190
191 /* Loop unrolling: Compute remaining outputs */
192 blkCnt = blockSize % 0x4U;
193
194 #else
195
196 /* Initialize blkCnt with number of samples */
197 blkCnt = blockSize;
198
199 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
200
201 while (blkCnt > 0U)
202 {
203 /* C = (float32_t) A / 128 */
204
205 /* Convert from q7 to float and store result in destination buffer */
206 *pDst++ = ((float32_t) * pIn++ / 128.0f);
207
208 /* Decrement loop counter */
209 blkCnt--;
210 }
211
212 }
213 #endif /* #if defined(ARM_MATH_NEON) */
214 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
215
216 /**
217 @} end of q7_to_x group
218 */
219