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_f16.h"
30
31 #if defined(ARM_FLOAT16_SUPPORTED)
32
33
34 /**
35 @ingroup groupSupport
36 */
37
38 /**
39 * @defgroup q15_to_x Convert 16-bit Integer value
40 */
41
42 /**
43 @addtogroup q15_to_x
44 @{
45 */
46
47 /**
48 @brief Converts the elements of the Q15 vector to f16 vector.
49 @param[in] pSrc points to the Q15 input vector
50 @param[out] pDst points to the f16 output vector
51 @param[in] blockSize number of samples in each vector
52 @return none
53
54 @par Details
55 The equation used for the conversion process is:
56 <pre>
57 pDst[n] = (float16_t) pSrc[n] / 32768; 0 <= n < blockSize.
58 </pre>
59 */
60
61 #if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE)
62
arm_q15_to_f16(const q15_t * pSrc,float16_t * pDst,uint32_t blockSize)63 void arm_q15_to_f16(
64 const q15_t * pSrc,
65 float16_t * pDst,
66 uint32_t blockSize)
67 {
68 int32_t blkCnt; /* loop counters */
69 q15x8_t vecDst;
70 q15_t const *pSrcVec;
71
72 pSrcVec = (q15_t const *) pSrc;
73 blkCnt = blockSize >> 3;
74 while (blkCnt > 0)
75 {
76 /* C = (float16_t) A / 32768 */
77 /* convert from q15 to float and then store the results in the destination buffer */
78 vecDst = vld1q(pSrcVec); pSrcVec += 8;
79 vstrhq(pDst, vcvtq_n_f16_s16(vecDst, 15)); pDst += 8;
80 /*
81 * Decrement the blockSize loop counter
82 */
83 blkCnt--;
84 }
85 /*
86 * tail
87 * (will be merged thru tail predication)
88 */
89 blkCnt = blockSize & 7;
90 if (blkCnt > 0)
91 {
92 mve_pred16_t p0 = vctp16q(blkCnt);
93 vecDst = vld1q(pSrcVec); pSrcVec += 8;
94 vstrhq_p(pDst, vcvtq_n_f16_s16(vecDst, 15), p0);
95 }
96 }
97 #else
98
arm_q15_to_f16(const q15_t * pSrc,float16_t * pDst,uint32_t blockSize)99 void arm_q15_to_f16(
100 const q15_t * pSrc,
101 float16_t * pDst,
102 uint32_t blockSize)
103 {
104 uint32_t blkCnt; /* Loop counter */
105 const q15_t *pIn = pSrc; /* Source pointer */
106
107 #if defined (ARM_MATH_LOOPUNROLL)
108
109 /* Loop unrolling: Compute 4 outputs at a time */
110 blkCnt = blockSize >> 2U;
111
112 while (blkCnt > 0U)
113 {
114 /* C = (float16_t) A / 32768 */
115
116 /* Convert from q15 to float and store result in destination buffer */
117 *pDst++ = ((float16_t) * pIn++ / 32768.0f);
118 *pDst++ = ((float16_t) * pIn++ / 32768.0f);
119 *pDst++ = ((float16_t) * pIn++ / 32768.0f);
120 *pDst++ = ((float16_t) * pIn++ / 32768.0f);
121
122 /* Decrement loop counter */
123 blkCnt--;
124 }
125
126 /* Loop unrolling: Compute remaining outputs */
127 blkCnt = blockSize % 0x4U;
128
129 #else
130
131 /* Initialize blkCnt with number of samples */
132 blkCnt = blockSize;
133
134 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
135
136 while (blkCnt > 0U)
137 {
138 /* C = (float16_t) A / 32768 */
139
140 /* Convert from q15 to float and store result in destination buffer */
141 *pDst++ = ((float16_t) *pIn++ / 32768.0f);
142
143 /* Decrement loop counter */
144 blkCnt--;
145 }
146
147 }
148 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
149
150 /**
151 @} end of q15_to_x group
152 */
153
154 #endif /* #if defined(ARM_FLOAT16_SUPPORTED) */
155
156
