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/******************************************************************************
* @file arm_math_utils.h
* @brief Public header file for CMSIS DSP Library
* @version V1.9.0
* @date 20. July 2020
******************************************************************************/
/*
* Copyright (c) 2010-2020 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.
*/
#ifndef _ARM_MATH_UTILS_H_
#define _ARM_MATH_UTILS_H_
#include "arm_math_types.h"
#ifdef __cplusplus
extern "C"
{
#endif
/**
* @brief Macros required for reciprocal calculation in Normalized LMS
*/
#define INDEX_MASK 0x0000003F
#define SQ(x) ((x) * (x))
#define ROUND_UP(N, S) ((((N) + (S) - 1) / (S)) * (S))
/**
* @brief Function to Calculates 1/in (reciprocal) value of Q31 Data type.
*/
__STATIC_FORCEINLINE uint32_t arm_recip_q31(
q31_t in,
q31_t * dst,
const q31_t * pRecipTable)
{
q31_t out;
uint32_t tempVal;
uint32_t index, i;
uint32_t signBits;
if (in > 0)
{
signBits = ((uint32_t) (__CLZ( in) - 1));
}
else
{
signBits = ((uint32_t) (__CLZ(-in) - 1));
}
/* Convert input sample to 1.31 format */
in = (in << signBits);
/* calculation of index for initial approximated Val */
index = (uint32_t)(in >> 24);
index = (index & INDEX_MASK);
/* 1.31 with exp 1 */
out = pRecipTable[index];
/* calculation of reciprocal value */
/* running approximation for two iterations */
for (i = 0U; i < 2U; i++)
{
tempVal = (uint32_t) (((q63_t) in * out) >> 31);
tempVal = 0x7FFFFFFFu - tempVal;
/* 1.31 with exp 1 */
/* out = (q31_t) (((q63_t) out * tempVal) >> 30); */
out = clip_q63_to_q31(((q63_t) out * tempVal) >> 30);
}
/* write output */
*dst = out;
/* return num of signbits of out = 1/in value */
return (signBits + 1U);
}
/**
* @brief Function to Calculates 1/in (reciprocal) value of Q15 Data type.
*/
__STATIC_FORCEINLINE uint32_t arm_recip_q15(
q15_t in,
q15_t * dst,
const q15_t * pRecipTable)
{
q15_t out = 0;
uint32_t tempVal = 0;
uint32_t index = 0, i = 0;
uint32_t signBits = 0;
if (in > 0)
{
signBits = ((uint32_t)(__CLZ( in) - 17));
}
else
{
signBits = ((uint32_t)(__CLZ(-in) - 17));
}
/* Convert input sample to 1.15 format */
in = (in << signBits);
/* calculation of index for initial approximated Val */
index = (uint32_t)(in >> 8);
index = (index & INDEX_MASK);
/* 1.15 with exp 1 */
out = pRecipTable[index];
/* calculation of reciprocal value */
/* running approximation for two iterations */
for (i = 0U; i < 2U; i++)
{
tempVal = (uint32_t) (((q31_t) in * out) >> 15);
tempVal = 0x7FFFu - tempVal;
/* 1.15 with exp 1 */
out = (q15_t) (((q31_t) out * tempVal) >> 14);
/* out = clip_q31_to_q15(((q31_t) out * tempVal) >> 14); */
}
/* write output */
*dst = out;
/* return num of signbits of out = 1/in value */
return (signBits + 1);
}
/**
* @brief 64-bit to 32-bit unsigned normalization
* @param[in] in is input unsigned long long value
* @param[out] normalized is the 32-bit normalized value
* @param[out] norm is norm scale
*/
__STATIC_INLINE void arm_norm_64_to_32u(uint64_t in, int32_t * normalized, int32_t *norm)
{
int32_t n1;
int32_t hi = (int32_t) (in >> 32);
int32_t lo = (int32_t) ((in << 32) >> 32);
n1 = __CLZ(hi) - 32;
if (!n1)
{
/*
* input fits in 32-bit
*/
n1 = __CLZ(lo);
if (!n1)
{
/*
* MSB set, need to scale down by 1
*/
*norm = -1;
*normalized = (((uint32_t) lo) >> 1);
} else
{
if (n1 == 32)
{
/*
* input is zero
*/
*norm = 0;
*normalized = 0;
} else
{
/*
* 32-bit normalization
*/
*norm = n1 - 1;
*normalized = lo << *norm;
}
}
} else
{
/*
* input fits in 64-bit
*/
n1 = 1 - n1;
*norm = -n1;
/*
* 64 bit normalization
*/
*normalized = (((uint32_t) lo) >> n1) | (hi << (32 - n1));
}
}
__STATIC_INLINE q31_t arm_div_q63_to_q31(q63_t num, q31_t den)
{
q31_t result;
uint64_t absNum;
int32_t normalized;
int32_t norm;
/*
* if sum fits in 32bits
* avoid costly 64-bit division
*/
absNum = num > 0 ? num : -num;
arm_norm_64_to_32u(absNum, &normalized, &norm);
if (norm > 0)
/*
* 32-bit division
*/
result = (q31_t) num / den;
else
/*
* 64-bit division
*/
result = (q31_t) (num / den);
return result;
}
#ifdef __cplusplus
}
#endif
#endif /*ifndef _ARM_MATH_UTILS_H_ */
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