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| 56 | mjames | 1 | /* ---------------------------------------------------------------------- |
| 2 | * Project: CMSIS DSP Library |
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| 3 | * Title: arm_float_to_q15.c |
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| 4 | * Description: Converts the elements of the floating-point vector to Q15 vector |
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| 5 | * |
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| 6 | * $Date: 27. January 2017 |
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| 7 | * $Revision: V.1.5.1 |
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| 8 | * |
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| 9 | * Target Processor: Cortex-M cores |
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| 10 | * -------------------------------------------------------------------- */ |
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| 11 | /* |
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| 12 | * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved. |
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| 13 | * |
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| 14 | * SPDX-License-Identifier: Apache-2.0 |
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| 15 | * |
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| 16 | * Licensed under the Apache License, Version 2.0 (the License); you may |
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| 17 | * not use this file except in compliance with the License. |
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| 18 | * You may obtain a copy of the License at |
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| 19 | * |
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| 20 | * www.apache.org/licenses/LICENSE-2.0 |
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| 21 | * |
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| 22 | * Unless required by applicable law or agreed to in writing, software |
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| 23 | * distributed under the License is distributed on an AS IS BASIS, WITHOUT |
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| 24 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 25 | * See the License for the specific language governing permissions and |
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| 26 | * limitations under the License. |
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| 27 | */ |
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| 28 | |||
| 29 | #include "arm_math.h" |
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| 30 | |||
| 31 | /** |
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| 32 | * @ingroup groupSupport |
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| 33 | */ |
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| 34 | |||
| 35 | /** |
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| 36 | * @addtogroup float_to_x |
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| 37 | * @{ |
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| 38 | */ |
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| 39 | |||
| 40 | /** |
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| 41 | * @brief Converts the elements of the floating-point vector to Q15 vector. |
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| 42 | * @param[in] *pSrc points to the floating-point input vector |
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| 43 | * @param[out] *pDst points to the Q15 output vector |
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| 44 | * @param[in] blockSize length of the input vector |
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| 45 | * @return none. |
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| 46 | * |
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| 47 | * \par Description: |
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| 48 | * \par |
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| 49 | * The equation used for the conversion process is: |
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| 50 | * <pre> |
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| 51 | * pDst[n] = (q15_t)(pSrc[n] * 32768); 0 <= n < blockSize. |
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| 52 | * </pre> |
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| 53 | * \par Scaling and Overflow Behavior: |
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| 54 | * \par |
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| 55 | * The function uses saturating arithmetic. |
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| 56 | * Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated. |
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| 57 | * \note |
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| 58 | * In order to apply rounding, the library should be rebuilt with the ROUNDING macro |
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| 59 | * defined in the preprocessor section of project options. |
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| 60 | * |
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| 61 | */ |
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| 62 | |||
| 63 | |||
| 64 | void arm_float_to_q15( |
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| 65 | float32_t * pSrc, |
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| 66 | q15_t * pDst, |
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| 67 | uint32_t blockSize) |
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| 68 | { |
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| 69 | float32_t *pIn = pSrc; /* Src pointer */ |
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| 70 | uint32_t blkCnt; /* loop counter */ |
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| 71 | |||
| 72 | #ifdef ARM_MATH_ROUNDING |
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| 73 | |||
| 74 | float32_t in; |
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| 75 | |||
| 76 | #endif /* #ifdef ARM_MATH_ROUNDING */ |
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| 77 | |||
| 78 | #if defined (ARM_MATH_DSP) |
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| 79 | |||
| 80 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
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| 81 | |||
| 82 | /*loop Unrolling */ |
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| 83 | blkCnt = blockSize >> 2U; |
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| 84 | |||
| 85 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
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| 86 | ** a second loop below computes the remaining 1 to 3 samples. */ |
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| 87 | while (blkCnt > 0U) |
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| 88 | { |
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| 89 | |||
| 90 | #ifdef ARM_MATH_ROUNDING |
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| 91 | /* C = A * 32768 */ |
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| 92 | /* convert from float to q15 and then store the results in the destination buffer */ |
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| 93 | in = *pIn++; |
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| 94 | in = (in * 32768.0f); |
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| 95 | in += in > 0.0f ? 0.5f : -0.5f; |
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| 96 | *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
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| 97 | |||
| 98 | in = *pIn++; |
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| 99 | in = (in * 32768.0f); |
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| 100 | in += in > 0.0f ? 0.5f : -0.5f; |
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| 101 | *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
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| 102 | |||
| 103 | in = *pIn++; |
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| 104 | in = (in * 32768.0f); |
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| 105 | in += in > 0.0f ? 0.5f : -0.5f; |
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| 106 | *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
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| 107 | |||
| 108 | in = *pIn++; |
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| 109 | in = (in * 32768.0f); |
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| 110 | in += in > 0.0f ? 0.5f : -0.5f; |
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| 111 | *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
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| 112 | |||
| 113 | #else |
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| 114 | |||
| 115 | /* C = A * 32768 */ |
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| 116 | /* convert from float to q15 and then store the results in the destination buffer */ |
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| 117 | *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
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| 118 | *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
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| 119 | *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
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| 120 | *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
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| 121 | |||
| 122 | #endif /* #ifdef ARM_MATH_ROUNDING */ |
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| 123 | |||
| 124 | /* Decrement the loop counter */ |
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| 125 | blkCnt--; |
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| 126 | } |
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| 127 | |||
| 128 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
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| 129 | ** No loop unrolling is used. */ |
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| 130 | blkCnt = blockSize % 0x4U; |
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| 131 | |||
| 132 | while (blkCnt > 0U) |
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| 133 | { |
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| 134 | |||
| 135 | #ifdef ARM_MATH_ROUNDING |
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| 136 | /* C = A * 32768 */ |
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| 137 | /* convert from float to q15 and then store the results in the destination buffer */ |
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| 138 | in = *pIn++; |
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| 139 | in = (in * 32768.0f); |
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| 140 | in += in > 0.0f ? 0.5f : -0.5f; |
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| 141 | *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
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| 142 | |||
| 143 | #else |
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| 144 | |||
| 145 | /* C = A * 32768 */ |
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| 146 | /* convert from float to q15 and then store the results in the destination buffer */ |
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| 147 | *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
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| 148 | |||
| 149 | #endif /* #ifdef ARM_MATH_ROUNDING */ |
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| 150 | |||
| 151 | /* Decrement the loop counter */ |
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| 152 | blkCnt--; |
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| 153 | } |
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| 154 | |||
| 155 | |||
| 156 | #else |
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| 157 | |||
| 158 | /* Run the below code for Cortex-M0 */ |
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| 159 | |||
| 160 | /* Loop over blockSize number of values */ |
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| 161 | blkCnt = blockSize; |
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| 162 | |||
| 163 | while (blkCnt > 0U) |
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| 164 | { |
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| 165 | |||
| 166 | #ifdef ARM_MATH_ROUNDING |
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| 167 | /* C = A * 32768 */ |
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| 168 | /* convert from float to q15 and then store the results in the destination buffer */ |
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| 169 | in = *pIn++; |
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| 170 | in = (in * 32768.0f); |
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| 171 | in += in > 0 ? 0.5f : -0.5f; |
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| 172 | *pDst++ = (q15_t) (__SSAT((q31_t) (in), 16)); |
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| 173 | |||
| 174 | #else |
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| 175 | |||
| 176 | /* C = A * 32768 */ |
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| 177 | /* convert from float to q15 and then store the results in the destination buffer */ |
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| 178 | *pDst++ = (q15_t) __SSAT((q31_t) (*pIn++ * 32768.0f), 16); |
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| 179 | |||
| 180 | #endif /* #ifdef ARM_MATH_ROUNDING */ |
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| 181 | |||
| 182 | /* Decrement the loop counter */ |
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| 183 | blkCnt--; |
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| 184 | } |
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| 185 | |||
| 186 | #endif /* #if defined (ARM_MATH_DSP) */ |
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| 187 | |||
| 188 | } |
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| 189 | |||
| 190 | /** |
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| 191 | * @} end of float_to_x group |
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| 192 | */ |