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 @return none
49
50 @par Details
51 The equation used for the conversion process is:
52 <pre>
53 pDst[n] = (q15_t)(pSrc[n] * 32768); 0 <= n < blockSize.
54 </pre>
55
56 @par Scaling and Overflow Behavior
57 The function uses saturating arithmetic.
58 Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
59
60 @note
61 In order to apply rounding in scalar version, the library should be rebuilt with the ROUNDING macro
62 defined in the preprocessor section of project options.
63 */
64
65 #if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE)
66
arm_f16_to_q15(const float16_t * pSrc,q15_t * pDst,uint32_t blockSize)67 void arm_f16_to_q15(
68 const float16_t * pSrc,
69 q15_t * pDst,
70 uint32_t blockSize)
71 {
72 float16_t maxQ = (float16_t) Q15_MAX;
73 float16x8_t vecDst;
74
75
76 do {
77 mve_pred16_t p = vctp16q(blockSize);
78
79 vecDst = vldrhq_z_f16((float16_t const *) pSrc, p);
80 /* C = A * 32767 */
81 /* convert from float to Q15 and then store the results in the destination buffer */
82 vecDst = vmulq_m(vuninitializedq_f16(), vecDst, maxQ, p);
83
84 vstrhq_p_s16(pDst,
85 vcvtaq_m(vuninitializedq_s16(), vecDst, p), p);
86 /*
87 * Decrement the blockSize loop counter
88 * Advance vector source and destination pointers
89 */
90 pSrc += 8;
91 pDst += 8;
92 blockSize -= 8;
93 }
94 while ((int32_t) blockSize > 0);
95 }
96
97 #else
98
arm_f16_to_q15(const float16_t * pSrc,q15_t * pDst,uint32_t blockSize)99 void arm_f16_to_q15(
100 const float16_t * pSrc,
101 q15_t * pDst,
102 uint32_t blockSize)
103 {
104 const float16_t *pIn = pSrc; /* Src pointer */
105 uint32_t blkCnt; /* loop counter */
106 #ifdef ARM_MATH_ROUNDING
107 float16_t in;
108 #endif /* #ifdef ARM_MATH_ROUNDING */
109
110 /*
111 * Loop over blockSize number of values
112 */
113 blkCnt = blockSize;
114
115 while (blkCnt > 0U)
116 {
117
118 #ifdef ARM_MATH_ROUNDING
119
120 /*
121 * C = A * 65536
122 */
123 /*
124 * convert from float to Q31 and then store the results in the destination buffer
125 */
126 in = *pIn++;
127 in = (in * 32768.0);
128 in += in > 0.0 ? 0.5 : -0.5;
129 *pDst++ = clip_q31_to_q15((q31_t) (in));
130
131 #else
132
133 /*
134 * C = A * 32768
135 */
136 /*
137 * convert from float to Q31 and then store the results in the destination buffer
138 */
139 *pDst++ = clip_q31_to_q15((q31_t) (*pIn++ * 32768.0));
140
141 #endif /* #ifdef ARM_MATH_ROUNDING */
142
143 /*
144 * Decrement the loop counter
145 */
146 blkCnt--;
147 }
148
149 }
150 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
151
152 /**
153 @} end of f16_to_x group
154 */
155
156 #endif /* #if defined(ARM_FLOAT16_SUPPORTED) */
157
158
