Download edge-impulse-sdk/CMSIS/DSP/Source/FastMathFunctions/arm_vlog_f16.c from edgeimpulse/Hey-Edge: direct link, hf CLI and curl.
- Browser
- Download file 5.5 kB
-
https://huggingface.co/edgeimpulse/Hey-Edge/resolve/main/edge-impulse-sdk/CMSIS/DSP/Source/FastMathFunctions/arm_vlog_f16.c
- Command line
-
hf download hf://edgeimpulse/Hey-Edge/edge-impulse-sdk/CMSIS/DSP/Source/FastMathFunctions/arm_vlog_f16.c
-
curl -L -o arm_vlog_f16.c https://huggingface.co/edgeimpulse/Hey-Edge/resolve/main/edge-impulse-sdk/CMSIS/DSP/Source/FastMathFunctions/arm_vlog_f16.c
5.5 kB
| /* ---------------------------------------------------------------------- | |
| * 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. | |
| */ | |
| /* Degree of the polynomial approximation */ | |
| /* | |
| Related to the Log2 of the number of approximations. | |
| For instance, with 3 there are 1 + 2^3 polynomials | |
| */ | |
| /* Length of the LUT table */ | |
| /* | |
| 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); | |
| } | |
| 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); | |
| } | |
| /** | |
| @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; | |
| 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; | |
| blkCnt = blockSize; | |
| 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 | |
| */ | |