1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_f64_to_q15.c
4 * Description: Converts the elements of the 64 bit floating-point vector to Q15 vector
5 *
6 * $Date: 18 August 2022
7 * $Revision: V1.0.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2022 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 f64_to_x
37 @{
38 */
39
40 /**
41 @brief Converts the elements of the 64 bit floating-point vector to Q15 vector.
42 @param[in] pSrc points to the 64 bit 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
46 @par Details
47 The equation used for the conversion process is:
48 <pre>
49 pDst[n] = (q15_t)(pSrc[n] * 32768); 0 <= n < blockSize.
50 </pre>
51
52 @par Scaling and Overflow Behavior
53 The function uses saturating arithmetic.
54 Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
55
56 @note
57 In order to apply rounding, the library should be rebuilt with the ROUNDING macro
58 defined in the preprocessor section of project options.
59 */
60
arm_f64_to_q15(const float64_t * pSrc,q15_t * pDst,uint32_t blockSize)61 void arm_f64_to_q15(
62 const float64_t * pSrc,
63 q15_t * pDst,
64 uint32_t blockSize)
65 {
66 uint32_t blkCnt; /* Loop counter */
67 const float64_t *pIn = pSrc; /* Source pointer */
68
69 #ifdef ARM_MATH_ROUNDING
70 float64_t in;
71 #endif /* #ifdef ARM_MATH_ROUNDING */
72
73 #if defined (ARM_MATH_LOOPUNROLL)
74
75 /* Loop unrolling: Compute 4 outputs at a time */
76 blkCnt = blockSize >> 2U;
77
78 while (blkCnt > 0U)
79 {
80 /* C = A * 32768 */
81
82 /* convert from float to Q15 and store result in destination buffer */
83 #ifdef ARM_MATH_ROUNDING
84 in = (*pIn++ * 32768.0);
85 in += in > 0.0 ? 0.5 : -0.5;
86 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
87
88 in = (*pIn++ * 32768.0);
89 in += in > 0.0 ? 0.5 : -0.5;
90 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
91
92 in = (*pIn++ * 32768.0);
93 in += in > 0.0 ? 0.5 : -0.5;
94 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
95
96 in = (*pIn++ * 32768.0);
97 in += in > 0.0 ? 0.5 : -0.5;
98 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
99
100 #else
101
102 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0), 16);
103 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0), 16);
104 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0), 16);
105 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0), 16);
106
107 #endif /* #ifdef ARM_MATH_ROUNDING */
108
109 /* Decrement loop counter */
110 blkCnt--;
111 }
112
113 /* Loop unrolling: Compute remaining outputs */
114 blkCnt = blockSize % 0x4U;
115
116 #else
117
118 /* Initialize blkCnt with number of samples */
119 blkCnt = blockSize;
120
121 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
122
123 while (blkCnt > 0U)
124 {
125 /* C = A * 32768 */
126
127 /* convert from float to Q15 and store result in destination buffer */
128 #ifdef ARM_MATH_ROUNDING
129
130 in = (*pIn++ * 32768.0);
131 in += in > 0.0 ? 0.5 : -0.5;
132 *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16));
133
134 #else
135
136 /* C = A * 32768 */
137 /* Convert from float to q15 and then store the results in the destination buffer */
138 *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0), 16);
139
140 #endif /* #ifdef ARM_MATH_ROUNDING */
141
142 /* Decrement loop counter */
143 blkCnt--;
144 }
145
146 }
147
148
149 /**
150 @} end of f64_to_x group
151 */
152
153
