| /* ---------------------------------------------------------------------- | |
| * Project: CMSIS DSP Library | |
| * Title: arm_linear_interp_f16.c | |
| * Description: Floating-point linear interpolation | |
| * | |
| * $Date: 23 April 2021 | |
| * $Revision: V1.9.0 | |
| * | |
| * Target Processor: Cortex-M and Cortex-A cores | |
| * -------------------------------------------------------------------- */ | |
| /* | |
| * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved. | |
| * | |
| * SPDX-License-Identifier: Apache-2.0 | |
| * | |
| * Licensed under the Apache License, Version 2.0 (the License); you may | |
| * not use this file except in compliance with the License. | |
| * You may obtain a copy of the License at | |
| * | |
| * www.apache.org/licenses/LICENSE-2.0 | |
| * | |
| * Unless required by applicable law or agreed to in writing, software | |
| * distributed under the License is distributed on an AS IS BASIS, WITHOUT | |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| * See the License for the specific language governing permissions and | |
| * limitations under the License. | |
| */ | |
| /** | |
| @ingroup groupInterpolation | |
| */ | |
| /** | |
| * @addtogroup LinearInterpolate | |
| * @{ | |
| */ | |
| /** | |
| * @brief Process function for the floating-point Linear Interpolation Function. | |
| * @param[in,out] S is an instance of the floating-point Linear Interpolation structure | |
| * @param[in] x input sample to process | |
| * @return y processed output sample. | |
| * | |
| */ | |
| float16_t arm_linear_interp_f16( | |
| arm_linear_interp_instance_f16 * S, | |
| float16_t x) | |
| { | |
| float16_t y; | |
| float16_t x0, x1; /* Nearest input values */ | |
| float16_t y0, y1; /* Nearest output values */ | |
| float16_t xSpacing = S->xSpacing; /* spacing between input values */ | |
| int32_t i; /* Index variable */ | |
| float16_t *pYData = S->pYData; /* pointer to output table */ | |
| /* Calculation of index */ | |
| i = (int32_t) (((_Float16)x - (_Float16)S->x1) / (_Float16)xSpacing); | |
| if (i < 0) | |
| { | |
| /* Iniatilize output for below specified range as least output value of table */ | |
| y = pYData[0]; | |
| } | |
| else if ((uint32_t)i >= (S->nValues - 1)) | |
| { | |
| /* Iniatilize output for above specified range as last output value of table */ | |
| y = pYData[S->nValues - 1]; | |
| } | |
| else | |
| { | |
| /* Calculation of nearest input values */ | |
| x0 = (_Float16)S->x1 + (_Float16)i * (_Float16)xSpacing; | |
| x1 = (_Float16)S->x1 + (_Float16)(i + 1) * (_Float16)xSpacing; | |
| /* Read of nearest output values */ | |
| y0 = pYData[i]; | |
| y1 = pYData[i + 1]; | |
| /* Calculation of output */ | |
| y = (_Float16)y0 + ((_Float16)x - (_Float16)x0) * | |
| (((_Float16)y1 - (_Float16)y0) / ((_Float16)x1 - (_Float16)x0)); | |
| } | |
| /* returns output value */ | |
| return (y); | |
| } | |
| /** | |
| * @} end of LinearInterpolate group | |
| */ | |