// SPDX-License-Identifier: BSD-3-Clause

//

// Copyright(c) 2021 Intel Corporation. All rights reserved.

//

// Author: Shriram Shastry <malladi.sastry@linux.intel.com>

//

//

#include <sof/math/log.h>

#include <sof/audio/format.h>

/**

* Base-e logarithm loge(x)

*

* loge = (u) computes the base-e logarithm of

* u using lookup table.

* input u must be scalar/real number and positive

*

* +------------------+-----------------+--------+--------+

* | inpfxp |loge (returntype)| inpfxp | loge |

* +----+-----+-------+----+----+-------+--------+--------+

* |WLen| FLen|Signbit|WLen|FLen|Signbit| Qformat| Qformat|

* +----+-----+-------+----+----+-------+--------+--------+

* | 32 | 0 | 0 | 32 | 27 | 0 | 32.0 | 5.27 |

* +------------------+-----------------+--------+--------+

*

* Arguments : uint32_t numerator [1 to 4294967295- Q32.0]

* Return Type : uint32_t UQ5.27 [ 0 to 22.1808076352]

*/

uint32_t ln_int32(uint32_t numerator)

{

return((uint32_t)Q_SHIFT_RND((int64_t)base2_logarithm(numerator) *

ONE_OVER_LOG2_E, 64, 32));

}