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_f16.h"
30
31 #if defined(ARM_FLOAT16_SUPPORTED)
32
33
34 /**
35 @ingroup groupSupport
36 */
37
38 /**
39 @addtogroup f16_to_x
40 @{
41 */
42
43 /**
44 @brief Converts the elements of the f16 vector to Q15 vector.
45 @param[in] pSrc points to the f16 input vector
46 @param[out] pDst points to the Q15 output vector
47 @param[in] blockSize number of samples in each vector
48
49 @par Details
50 The equation used for the conversion process is:
51 <pre>
52 pDst[n] = (q15_t)(pSrc[n] * 32768); 0 <= n < blockSize.
53 </pre>
54
55 @par Scaling and Overflow Behavior
56 The function uses saturating arithmetic.
57 Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
58
59 @note
60 In order to apply rounding in scalar version, the library should be rebuilt with the ROUNDING macro
61 defined in the preprocessor section of project options.
62 */
63
64 #if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE)
65
arm_f16_to_q15(const float16_t * pSrc,q15_t * pDst,uint32_t blockSize)66 ARM_DSP_ATTRIBUTE void arm_f16_to_q15(
67 const float16_t * pSrc,
68 q15_t * pDst,
69 uint32_t blockSize)
70 {
71 float16_t maxQ = (float16_t) Q15_MAX;
72 float16x8_t vecDst;
73
74
75 do {
76 mve_pred16_t p = vctp16q(blockSize);
77
78 vecDst = vldrhq_z_f16((float16_t const *) pSrc, p);
79 /* C = A * 32767 */
80 /* convert from float to Q15 and then store the results in the destination buffer */
81 vecDst = vmulq_m(vuninitializedq_f16(), vecDst, maxQ, p);
82
83 vstrhq_p_s16(pDst,
84 vcvtaq_m(vuninitializedq_s16(), vecDst, p), p);
85 /*
86 * Decrement the blockSize loop counter
87 * Advance vector source and destination pointers
88 */
89 pSrc += 8;
90 pDst += 8;
91 blockSize -= 8;
92 }
93 while ((int32_t) blockSize > 0);
94 }
95
96 #else
97
arm_f16_to_q15(const float16_t * pSrc,q15_t * pDst,uint32_t blockSize)98 ARM_DSP_ATTRIBUTE void arm_f16_to_q15(
99 const float16_t * pSrc,
100 q15_t * pDst,
101 uint32_t blockSize)
102 {
103 const float16_t *pIn = pSrc; /* Src pointer */
104 uint32_t blkCnt; /* loop counter */
105 #ifdef ARM_MATH_ROUNDING
106 float16_t in;
107 #endif /* #ifdef ARM_MATH_ROUNDING */
108
109 /*
110 * Loop over blockSize number of values
111 */
112 blkCnt = blockSize;
113
114 while (blkCnt > 0U)
115 {
116
117 #ifdef ARM_MATH_ROUNDING
118
119 /*
120 * C = A * 65536
121 */
122 /*
123 * convert from float to Q31 and then store the results in the destination buffer
124 */
125 in = *pIn++;
126 in = ((_Float16)in * (_Float16)32768.0f16);
127 in += (_Float16)in > 0.0f16 ? 0.5f16 : -0.5f16;
128 *pDst++ = clip_q31_to_q15((q31_t) (in));
129
130 #else
131
132 /*
133 * C = A * 32768
134 */
135 /*
136 * convert from float to Q31 and then store the results in the destination buffer
137 */
138 *pDst++ = clip_q31_to_q15((q31_t) ((_Float16)*pIn++ * 32768.0f16));
139
140 #endif /* #ifdef ARM_MATH_ROUNDING */
141
142 /*
143 * Decrement the loop counter
144 */
145 blkCnt--;
146 }
147
148 }
149 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
150
151 /**
152 @} end of f16_to_x group
153 */
154
155 #endif /* #if defined(ARM_FLOAT16_SUPPORTED) */
156
157
