sfizz/src/external/hiir/Downsampler2xSse.hpp
2020-02-27 14:07:09 +01:00

322 lines
9.1 KiB
C++

/*****************************************************************************
Downsampler2xSse.hpp
Author: Laurent de Soras, 2005
--- Legal stuff ---
This program is free software. It comes without any warranty, to
the extent permitted by applicable law. You can redistribute it
and/or modify it under the terms of the Do What The Fuck You Want
To Public License, Version 2, as published by Sam Hocevar. See
http://sam.zoy.org/wtfpl/COPYING for more details.
*Tab=3***********************************************************************/
#if defined (hiir_Downsampler2xSse_CURRENT_CODEHEADER)
#error Recursive inclusion of Downsampler2xSse code header.
#endif
#define hiir_Downsampler2xSse_CURRENT_CODEHEADER
#if ! defined (hiir_Downsampler2xSse_CODEHEADER_INCLUDED)
#define hiir_Downsampler2xSse_CODEHEADER_INCLUDED
/*\\\ INCLUDE FILES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/
#include "hiir/StageProcSse.h"
#include <xmmintrin.h>
#include <cassert>
namespace hiir
{
/*\\\ PUBLIC \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/
/*
==============================================================================
Name: ctor
Throws: Nothing
==============================================================================
*/
template <int NC>
Downsampler2xSse <NC>::Downsampler2xSse ()
: _filter ()
{
for (int i = 0; i < NBR_STAGES + 1; ++i)
{
_filter [i]._coef [0] = 0;
_filter [i]._coef [1] = 0;
_filter [i]._coef [2] = 0;
_filter [i]._coef [3] = 0;
}
if ((NBR_COEFS & 1) != 0)
{
const int pos = (NBR_COEFS ^ 1) & (STAGE_WIDTH - 1);
_filter [NBR_STAGES]._coef [pos] = 1;
}
clear_buffers ();
}
/*
==============================================================================
Name: set_coefs
Description:
Sets filter coefficients. Generate them with the PolyphaseIir2Designer
class.
Call this function before doing any processing.
Input parameters:
- coef_arr: Array of coefficients. There should be as many coefficients as
mentioned in the class template parameter.
Throws: Nothing
==============================================================================
*/
template <int NC>
void Downsampler2xSse <NC>::set_coefs (const double coef_arr [])
{
assert (coef_arr != 0);
for (int i = 0; i < NBR_COEFS; ++i)
{
const int stage = (i / STAGE_WIDTH) + 1;
const int pos = (i ^ 1) & (STAGE_WIDTH - 1);
_filter [stage]._coef [pos] = float (coef_arr [i]);
}
}
/*
==============================================================================
Name: process_sample
Description:
Downsamples (x2) one pair of samples, to generate one output sample.
Input parameters:
- in_ptr: pointer on the two samples to decimate
Returns: Samplerate-reduced sample.
Throws: Nothing
==============================================================================
*/
template <int NC>
float Downsampler2xSse <NC>::process_sample (const float in_ptr [2])
{
assert (in_ptr != 0);
// Combines two input samples and two mid-processing data
const __m128 spl_in = _mm_loadu_ps (in_ptr);
const __m128 spl_mid = _mm_load_ps (_filter [NBR_STAGES]._mem);
__m128 y = _mm_shuffle_ps (spl_in, spl_mid, 0x44);
__m128 mem = _mm_load_ps (_filter [0]._mem);
// Processes each stage
StageProcSse <NBR_STAGES>::process_sample_pos (&_filter [0], y, mem);
_mm_store_ps (_filter [NBR_STAGES]._mem, y);
// Averages both paths and outputs the result
const __m128 dup_y = y;
y = _mm_shuffle_ps (y, y, 0x80);
y = _mm_add_ps (y, dup_y);
y = _mm_shuffle_ps (y, y, 3);
y = _mm_mul_ss (y, _mm_set_ss (0.5f));
float result;
_mm_store_ss (&result, y);
return (result);
}
/*
==============================================================================
Name: process_block
Description:
Downsamples (x2) a block of samples.
Input and output blocks may overlap, see assert() for details.
Input parameters:
- in_ptr: Input array, containing nbr_spl * 2 samples.
- nbr_spl: Number of samples to output, > 0
Output parameters:
- out_ptr: Array for the output samples, capacity: nbr_spl samples.
Throws: Nothing
==============================================================================
*/
template <int NC>
void Downsampler2xSse <NC>::process_block (float out_ptr [], const float in_ptr [], long nbr_spl)
{
assert (in_ptr != 0);
assert (out_ptr != 0);
assert (out_ptr <= in_ptr || out_ptr >= in_ptr + nbr_spl * 2);
assert (nbr_spl > 0);
long pos = 0;
do
{
out_ptr [pos] = process_sample (in_ptr + pos * 2);
++ pos;
}
while (pos < nbr_spl);
}
/*
==============================================================================
Name: process_sample_split
Description:
Split (spectrum-wise) in half a pair of samples. The lower part of the
spectrum is a classic downsampling, equivalent to the output of
process_sample().
The higher part is the complementary signal: original filter response
is flipped from left to right, becoming a high-pass filter with the same
cutoff frequency. This signal is then critically sampled (decimation by 2),
flipping the spectrum: Fs/4...Fs/2 becomes Fs/4...0.
Input parameters:
- in_ptr: pointer on the pair of input samples
Output parameters:
- low: output sample, lower part of the spectrum (downsampling)
- high: output sample, higher part of the spectrum.
Throws: Nothing
==============================================================================
*/
template <int NC>
void Downsampler2xSse <NC>::process_sample_split (float &low, float &high, const float in_ptr [2])
{
assert (in_ptr != 0);
// Combines two input samples and two mid-processing data
const __m128 spl_in = _mm_loadu_ps (in_ptr);
const __m128 spl_mid = _mm_load_ps (_filter [NBR_STAGES]._mem);
__m128 y = _mm_shuffle_ps (spl_in, spl_mid, 0x44);
__m128 mem = _mm_load_ps (_filter [0]._mem);
// Processes each stage
StageProcSse <NBR_STAGES>::process_sample_pos (&_filter [0], y, mem);
_mm_store_ps (_filter [NBR_STAGES]._mem, y);
//Outputs the result
__m128 dup_y = y;
y = _mm_shuffle_ps (y, y, 0x80);
y = _mm_add_ps (y, dup_y);
y = _mm_shuffle_ps (y, y, 3);
y = _mm_mul_ss (y, _mm_set_ss (0.5f));
_mm_store_ss (&low, y);
dup_y = _mm_shuffle_ps (dup_y, dup_y, 3);
dup_y = _mm_sub_ps (dup_y, y);
_mm_store_ss (&high, dup_y);
}
/*
==============================================================================
Name: process_block_split
Description:
Split (spectrum-wise) in half a block of samples. The lower part of the
spectrum is a classic downsampling, equivalent to the output of
process_block().
The higher part is the complementary signal: original filter response
is flipped from left to right, becoming a high-pass filter with the same
cutoff frequency. This signal is then critically sampled (decimation by 2),
flipping the spectrum: Fs/4...Fs/2 becomes Fs/4...0.
Input and output blocks may overlap, see assert() for details.
Input parameters:
- in_ptr: Input array, containing nbr_spl * 2 samples.
- nbr_spl: Number of samples for each output, > 0
Output parameters:
- out_l_ptr: Array for the output samples, lower part of the spectrum
(downsampling). Capacity: nbr_spl samples.
- out_h_ptr: Array for the output samples, higher part of the spectrum.
Capacity: nbr_spl samples.
Throws: Nothing
==============================================================================
*/
template <int NC>
void Downsampler2xSse <NC>::process_block_split (float out_l_ptr [], float out_h_ptr [], const float in_ptr [], long nbr_spl)
{
assert (in_ptr != 0);
assert (out_l_ptr != 0);
assert (out_l_ptr <= in_ptr || out_l_ptr >= in_ptr + nbr_spl * 2);
assert (out_h_ptr != 0);
assert (out_h_ptr <= in_ptr || out_h_ptr >= in_ptr + nbr_spl * 2);
assert (out_h_ptr != out_l_ptr);
assert (nbr_spl > 0);
long pos = 0;
do
{
process_sample_split (out_l_ptr [pos], out_h_ptr [pos], in_ptr + pos * 2);
++ pos;
}
while (pos < nbr_spl);
}
/*
==============================================================================
Name: clear_buffers
Description:
Clears filter memory, as if it processed silence since an infinite amount
of time.
Throws: Nothing
==============================================================================
*/
template <int NC>
void Downsampler2xSse <NC>::clear_buffers ()
{
for (int i = 0; i < NBR_STAGES + 1; ++i)
{
_filter [i]._mem [0] = 0;
_filter [i]._mem [1] = 0;
_filter [i]._mem [2] = 0;
_filter [i]._mem [3] = 0;
}
}
/*\\\ PROTECTED \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/
/*\\\ PRIVATE \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/
} // namespace hiir
#endif // hiir_Downsampler2xSse_CODEHEADER_INCLUDED
#undef hiir_Downsampler2xSse_CURRENT_CODEHEADER
/*\\\ EOF \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/