1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_float_to_q15.c
4 * Description: Converts the elements of the floating-point vector to Q15 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 @addtogroup float_to_x
37 @{
38 */
39
40 /**
41 @brief Converts the elements of the floating-point vector to Q15 vector.
42 @param[in] pSrc points to the floating-point input vector
43 @param[out] pDst points to the Q15 output vector
44 @param[in] blockSize number of samples in each vector
45 @return none
46
47 @par Details
48 The equation used for the conversion process is:
49 <pre>
50 pDst[n] = (q15_t)(pSrc[n] * 32768); 0 <= n < blockSize.
51 </pre>
52
53 @par Scaling and Overflow Behavior
54 The function uses saturating arithmetic.
55 Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
56
57 @note
58 In order to apply rounding, the library should be rebuilt with the ROUNDING macro
59 defined in the preprocessor section of project options.
60 */
61
62 #if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
arm_float_to_q15(const float32_t * pSrc,q15_t * pDst,uint32_t blockSize)63 void arm_float_to_q15(
64 const float32_t * pSrc,
65 q15_t * pDst,
66 uint32_t blockSize)
67 {
68 uint32_t blkCnt;
69 float32_t maxQ = (float32_t) Q15_MAX;
70 f32x4x2_t tmp;
71 q15x8_t vecDst = { 0 };
72 #ifdef ARM_MATH_ROUNDING
73 float32_t in;
74 #endif
75
76
77 blkCnt = blockSize >> 3;
78 while (blkCnt > 0U)
79 {
80 /* C = A * 32768 */
81 /* convert from float to q15 and then store the results in the destination buffer */
82 tmp = vld2q(pSrc);
83
84 tmp.val[0] = vmulq(tmp.val[0], maxQ);
85 tmp.val[1] = vmulq(tmp.val[1], maxQ);
86
87 vecDst = vqmovnbq(vecDst, vcvtaq_s32_f32(tmp.val[0]));
88 vecDst = vqmovntq(vecDst, vcvtaq_s32_f32(tmp.val[1]));
89 vst1q(pDst, vecDst);
90 /*
91 * Decrement the blockSize loop counter
92 */
93 blkCnt--;
94 pDst += 8;
95 pSrc += 8;
96 }
97
98 blkCnt = blockSize & 7;
99 while (blkCnt > 0U)
100 {
101 /* C = A * 32768 */
102
103 /* convert from float to Q15 and store result in destination buffer */
104 #ifdef ARM_MATH_ROUNDING
105
106 in = (*pSrc++ * 32768.0f);
107 in += in > 0.0f ? 0.5f : -0.5f;
108 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
109
110 #else
111
112 /* C = A * 32768 */
113 /* Convert from float to q15 and then store the results in the destination buffer */
114 *pDst++ = (q15_t) __SSAT((q31_t) (*pSrc++ * 32768.0f), 16);
115
116 #endif /* #ifdef ARM_MATH_ROUNDING */
117
118 /* Decrement loop counter */
119 blkCnt--;
120 }
121 }
122
123 #else
124 #if defined(ARM_MATH_NEON_EXPERIMENTAL)
arm_float_to_q15(const float32_t * pSrc,q15_t * pDst,uint32_t blockSize)125 void arm_float_to_q15(
126 const float32_t * pSrc,
127 q15_t * pDst,
128 uint32_t blockSize)
129 {
130 const float32_t *pIn = pSrc; /* Src pointer */
131 uint32_t blkCnt; /* loop counter */
132
133 float32x4_t inV;
134 #ifdef ARM_MATH_ROUNDING
135 float32x4_t zeroV = vdupq_n_f32(0.0f);
136 float32x4_t pHalf = vdupq_n_f32(0.5f / 32768.0f);
137 float32x4_t mHalf = vdupq_n_f32(-0.5f / 32768.0f);
138 float32x4_t r;
139 uint32x4_t cmp;
140 float32_t in;
141 #endif
142
143 int32x4_t cvt;
144 int16x4_t outV;
145
146 blkCnt = blockSize >> 2U;
147
148 /* Compute 4 outputs at a time.
149 ** a second loop below computes the remaining 1 to 3 samples. */
150 while (blkCnt > 0U)
151 {
152
153 #ifdef ARM_MATH_ROUNDING
154 /* C = A * 32768 */
155 /* Convert from float to q15 and then store the results in the destination buffer */
156 inV = vld1q_f32(pIn);
157 cmp = vcgtq_f32(inV,zeroV);
158 r = vbslq_f32(cmp,pHalf,mHalf);
159 inV = vaddq_f32(inV, r);
160
161 pIn += 4;
162
163 cvt = vcvtq_n_s32_f32(inV,15);
164 outV = vqmovn_s32(cvt);
165
166 vst1_s16(pDst, outV);
167 pDst += 4;
168
169 #else
170
171 /* C = A * 32768 */
172 /* Convert from float to q15 and then store the results in the destination buffer */
173 inV = vld1q_f32(pIn);
174
175 cvt = vcvtq_n_s32_f32(inV,15);
176 outV = vqmovn_s32(cvt);
177
178 vst1_s16(pDst, outV);
179 pDst += 4;
180 pIn += 4;
181
182 #endif /* #ifdef ARM_MATH_ROUNDING */
183
184 /* Decrement the loop counter */
185 blkCnt--;
186 }
187
188 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
189 ** No loop unrolling is used. */
190 blkCnt = blockSize & 3;
191
192 while (blkCnt > 0U)
193 {
194
195 #ifdef ARM_MATH_ROUNDING
196 /* C = A * 32768 */
197 /* Convert from float to q15 and then store the results in the destination buffer */
198 in = *pIn++;
199 in = (in * 32768.0f);
200 in += in > 0.0f ? 0.5f : -0.5f;
201 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
202
203 #else
204
205 /* C = A * 32768 */
206 /* Convert from float to q15 and then store the results in the destination buffer */
207 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16);
208
209 #endif /* #ifdef ARM_MATH_ROUNDING */
210
211 /* Decrement the loop counter */
212 blkCnt--;
213 }
214 }
215 #else
arm_float_to_q15(const float32_t * pSrc,q15_t * pDst,uint32_t blockSize)216 void arm_float_to_q15(
217 const float32_t * pSrc,
218 q15_t * pDst,
219 uint32_t blockSize)
220 {
221 uint32_t blkCnt; /* Loop counter */
222 const float32_t *pIn = pSrc; /* Source pointer */
223
224 #ifdef ARM_MATH_ROUNDING
225 float32_t in;
226 #endif /* #ifdef ARM_MATH_ROUNDING */
227
228 #if defined (ARM_MATH_LOOPUNROLL)
229
230 /* Loop unrolling: Compute 4 outputs at a time */
231 blkCnt = blockSize >> 2U;
232
233 while (blkCnt > 0U)
234 {
235 /* C = A * 32768 */
236
237 /* convert from float to Q15 and store result in destination buffer */
238 #ifdef ARM_MATH_ROUNDING
239
240 in = (*pIn++ * 32768.0f);
241 in += in > 0.0f ? 0.5f : -0.5f;
242 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
243
244 in = (*pIn++ * 32768.0f);
245 in += in > 0.0f ? 0.5f : -0.5f;
246 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
247
248 in = (*pIn++ * 32768.0f);
249 in += in > 0.0f ? 0.5f : -0.5f;
250 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
251
252 in = (*pIn++ * 32768.0f);
253 in += in > 0.0f ? 0.5f : -0.5f;
254 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
255
256 #else
257
258 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16);
259 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16);
260 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16);
261 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16);
262
263 #endif /* #ifdef ARM_MATH_ROUNDING */
264
265 /* Decrement loop counter */
266 blkCnt--;
267 }
268
269 /* Loop unrolling: Compute remaining outputs */
270 blkCnt = blockSize % 0x4U;
271
272 #else
273
274 /* Initialize blkCnt with number of samples */
275 blkCnt = blockSize;
276
277 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
278
279 while (blkCnt > 0U)
280 {
281 /* C = A * 32768 */
282
283 /* convert from float to Q15 and store result in destination buffer */
284 #ifdef ARM_MATH_ROUNDING
285
286 in = (*pIn++ * 32768.0f);
287 in += in > 0.0f ? 0.5f : -0.5f;
288 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
289
290 #else
291
292 /* C = A * 32768 */
293 /* Convert from float to q15 and then store the results in the destination buffer */
294 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16);
295
296 #endif /* #ifdef ARM_MATH_ROUNDING */
297
298 /* Decrement loop counter */
299 blkCnt--;
300 }
301
302 }
303 #endif /* #if defined(ARM_MATH_NEON) */
304 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
305
306 /**
307 @} end of float_to_x group
308 */
309