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Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_vlog_f16.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_vlog_f16.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_vlog_f16.c b/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_vlog_f16.c new file mode 100644 index 0000000..0821d5a --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_vlog_f16.c @@ -0,0 +1,222 @@ +/* ---------------------------------------------------------------------- + * Project: CMSIS DSP Library + * Title: arm_vlog_f16.c + * Description: Fast vectorized log + * + * $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/fast_math_functions_f16.h" +#include "dsp/support_functions_f16.h" + +#if defined(ARM_FLOAT16_SUPPORTED) + +/* Degree of the polynomial approximation */ +#define NB_DEG_LOGF16 3 + +/* +Related to the Log2 of the number of approximations. +For instance, with 3 there are 1 + 2^3 polynomials +*/ +#define NB_DIV_LOGF16 3 + +/* Length of the LUT table */ +#define NB_LUT_LOGF16 (NB_DEG_LOGF16+1)*(1 + (1<<NB_DIV_LOGF16)) + + +/* + +LUT of polynomial approximations. + +Could be generated with: + +ClearAll[lut, coefs, nb, deg]; +nb = 3; +deg = 3; +lut = Table[ + MiniMaxApproximation[ + Log[x/2^nb + i], {x, {10^-6, 1.0/2^nb}, deg, 0}, + MaxIterations -> 1000][[2, 1]], {i, 1, 2, (1.0/2^nb)}]; +coefs = Chop@Flatten[CoefficientList[lut, x]]; + +*/ +static float16_t lut_logf16[NB_LUT_LOGF16]={ + 0,0.125,-0.00781197,0.00063974,0.117783, + 0.111111,-0.00617212,0.000447935,0.223144, + 0.1,-0.00499952,0.000327193,0.318454,0.0909091, + -0.00413191,0.000246234,0.405465,0.0833333, + -0.00347199,0.000189928,0.485508,0.0769231, + -0.00295841,0.00014956,0.559616,0.0714286, + -0.0025509,0.000119868,0.628609,0.0666667, + -0.00222213,0.0000975436,0.693147, + 0.0625,-0.00195305,0.0000804357}; + + +float16_t logf16_scalar(float16_t x) +{ + int16_t i = arm_typecast_s16_f16(x); + + int32_t vecExpUnBiased = (i >> 10) - 15; + i = i - (vecExpUnBiased << 10); + float16_t vecTmpFlt1 = arm_typecast_f16_s16(i); + + float16_t *lut; + int n; + float16_t tmp,v; + + tmp = ((_Float16)vecTmpFlt1 - 1.0f16) * (1 << NB_DIV_LOGF16); + n = (int)floor((double)tmp); + v = (_Float16)tmp - (_Float16)n; + + lut = lut_logf16 + n * (1+NB_DEG_LOGF16); + + float16_t res = lut[NB_DEG_LOGF16-1]; + for(int j=NB_DEG_LOGF16-2; j >=0 ; j--) + { + res = (_Float16)lut[j] + (_Float16)v * (_Float16)res; + } + + res = (_Float16)res + 0.693147f16 * (_Float16)vecExpUnBiased; + + + return(res); +} + +#if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE) + +#include "arm_common_tables.h" +#include "arm_vec_math_f16.h" + + +float16x8_t vlogq_lut_f16(float16x8_t vecIn) +{ + int16x8_t i = vreinterpretq_s16_f16(vecIn); + + int16x8_t vecExpUnBiased = vsubq_n_s16(vshrq_n_s16(i,10), 15); + i = vsubq_s16(i,vshlq_n_s16(vecExpUnBiased,10)); + float16x8_t vecTmpFlt1 = vreinterpretq_f16_s16(i); + + + float16x8_t lutV; + int16x8_t n; + int16x8_t offset; + + float16x8_t tmp,v,res; + + tmp = vmulq_n_f16(vsubq_n_f16(vecTmpFlt1,1.0f16),(_Float16)(1 << NB_DIV_LOGF16)); + + n = vcvtq_s16_f16(tmp); + v = vsubq_f16(tmp,vcvtq_f16_s16(n)); + + + offset = vmulq_n_s16(n,(1+NB_DEG_LOGF16)); + offset = vaddq_n_s16(offset,NB_DEG_LOGF16-1); + + res = vldrhq_gather_shifted_offset_f16(lut_logf16,(uint16x8_t)offset); + offset = vsubq_n_s16(offset,1); + + for(int j=NB_DEG_LOGF16-2; j >=0 ; j--) + { + lutV = vldrhq_gather_shifted_offset_f16(lut_logf16,(uint16x8_t)offset); + res = vfmaq_f16(lutV,v,res); + offset = vsubq_n_s16(offset,1); + + } + + res = vfmaq_n_f16(res,vcvtq_f16_s16(vecExpUnBiased),0.693147f16); + + + return(res); + +} + +#endif + +/** + @ingroup groupFastMath + */ + +/** + @addtogroup vlog + @{ + */ + +/** + @brief Floating-point vector of log values. + @param[in] pSrc points to the input vector + @param[out] pDst points to the output vector + @param[in] blockSize number of samples in each vector + @return none + */ + + +void arm_vlog_f16( + const float16_t * pSrc, + float16_t * pDst, + uint32_t blockSize) +{ + uint32_t blkCnt; + +#if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE) + f16x8_t src; + f16x8_t dst; + + blkCnt = blockSize >> 3; + + while (blkCnt > 0U) + { + src = vld1q(pSrc); + dst = vlogq_lut_f16(src); + vst1q(pDst, dst); + + pSrc += 8; + pDst += 8; + /* Decrement loop counter */ + blkCnt--; + } + + blkCnt = blockSize & 7; +#else + blkCnt = blockSize; +#endif + + while (blkCnt > 0U) + { + /* C = log(A) */ + + /* Calculate log and store result in destination buffer. */ + *pDst++ = logf16_scalar(*pSrc++); + + /* Decrement loop counter */ + blkCnt--; + } +} + + + +/** + @} end of vlog group + */ + + +#endif /* #if defined(ARM_FLOAT16_SUPPORTED) */ |