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Diffstat (limited to 'Drivers/CMSIS/DSP/Source/InterpolationFunctions/arm_bilinear_interp_q7.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/InterpolationFunctions/arm_bilinear_interp_q7.c | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/InterpolationFunctions/arm_bilinear_interp_q7.c b/Drivers/CMSIS/DSP/Source/InterpolationFunctions/arm_bilinear_interp_q7.c new file mode 100644 index 0000000..204342e --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/InterpolationFunctions/arm_bilinear_interp_q7.c @@ -0,0 +1,117 @@ +/* ---------------------------------------------------------------------- + * Project: CMSIS DSP Library + * Title: arm_linear_interp_q7.c + * Description: Q7 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. + */ + +#include "dsp/interpolation_functions.h" + +/** + @ingroup groupInterpolation + */ + + +/** + * @addtogroup BilinearInterpolate + * @{ + */ + +/** + * @brief Q7 bilinear interpolation. + * @param[in,out] S points to an instance of the interpolation structure. + * @param[in] X interpolation coordinate in 12.20 format. + * @param[in] Y interpolation coordinate in 12.20 format. + * @return out interpolated value. + */ + q7_t arm_bilinear_interp_q7( + arm_bilinear_interp_instance_q7 * S, + q31_t X, + q31_t Y) + { + q63_t acc = 0; /* output */ + q31_t out; /* Temporary output */ + q31_t xfract, yfract; /* X, Y fractional parts */ + q7_t x1, x2, y1, y2; /* Nearest output values */ + int32_t rI, cI; /* Row and column indices */ + q7_t *pYData = S->pData; /* pointer to output table values */ + uint32_t nCols = S->numCols; /* num of rows */ + + /* Input is in 12.20 format */ + /* 12 bits for the table index */ + /* Index value calculation */ + rI = ((X & (q31_t)0xFFF00000) >> 20); + + /* Input is in 12.20 format */ + /* 12 bits for the table index */ + /* Index value calculation */ + cI = ((Y & (q31_t)0xFFF00000) >> 20); + + /* Care taken for table outside boundary */ + /* Returns zero output when values are outside table boundary */ + if (rI < 0 || rI > (S->numCols - 2) || cI < 0 || cI > (S->numRows - 2)) + { + return (0); + } + + /* 20 bits for the fractional part */ + /* xfract should be in 12.20 format */ + xfract = (X & (q31_t)0x000FFFFF); + + /* Read two nearest output values from the index */ + x1 = pYData[((uint32_t)rI) + nCols * ((uint32_t)cI) ]; + x2 = pYData[((uint32_t)rI) + nCols * ((uint32_t)cI) + 1]; + + /* 20 bits for the fractional part */ + /* yfract should be in 12.20 format */ + yfract = (Y & (q31_t)0x000FFFFF); + + /* Read two nearest output values from the index */ + y1 = pYData[((uint32_t)rI) + nCols * ((uint32_t)cI + 1) ]; + y2 = pYData[((uint32_t)rI) + nCols * ((uint32_t)cI + 1) + 1]; + + /* Calculation of x1 * (1-xfract ) * (1-yfract) and acc is in 16.47 format */ + out = ((x1 * (0xFFFFF - xfract))); + acc = (((q63_t) out * (0xFFFFF - yfract))); + + /* x2 * (xfract) * (1-yfract) in 2.22 and adding to acc */ + out = ((x2 * (0xFFFFF - yfract))); + acc += (((q63_t) out * (xfract))); + + /* y1 * (1 - xfract) * (yfract) in 2.22 and adding to acc */ + out = ((y1 * (0xFFFFF - xfract))); + acc += (((q63_t) out * (yfract))); + + /* y2 * (xfract) * (yfract) in 2.22 and adding to acc */ + out = ((y2 * (yfract))); + acc += (((q63_t) out * (xfract))); + + /* acc in 16.47 format and down shift by 40 to convert to 1.7 format */ + return ((q7_t)(acc >> 40)); + } + + /** + * @} end of BilinearInterpolate group + */ + |