mirror of
https://github.com/RaySollium99/picodrive.git
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195 lines
6.9 KiB
C
195 lines
6.9 KiB
C
/*
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* Copyright (C) 2013 - Hans-Kristian Arntzen
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*
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* Permission is hereby granted, free of charge,
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* to any person obtaining a copy of this software and
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* associated documentation files (the "Software"),
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* to deal in the Software without restriction,
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* including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#ifndef BLIPPER_H__
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#define BLIPPER_H__
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Compile time configurables. */
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#ifndef BLIPPER_LOG_PERFORMANCE
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#define BLIPPER_LOG_PERFORMANCE 0
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#endif
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#ifndef BLIPPER_FIXED_POINT
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#define BLIPPER_FIXED_POINT 1
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#endif
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/* Set to float or double.
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* long double is unlikely to provide any improved precision. */
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#ifndef BLIPPER_REAL_T
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#define BLIPPER_REAL_T float
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#endif
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/* Allows including several implementations in one lib. */
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#if BLIPPER_FIXED_POINT
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#define BLIPPER_MANGLE(x) x##_fixed
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#else
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#define BLIPPER_CONCAT2(a, b) a ## b
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#define BLIPPER_CONCAT(a, b) BLIPPER_CONCAT2(a, b)
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#define BLIPPER_MANGLE(x) BLIPPER_CONCAT(x##_, BLIPPER_REAL_T)
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#endif
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#include <limits.h>
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typedef struct blipper blipper_t;
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typedef BLIPPER_REAL_T blipper_real_t;
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#if BLIPPER_FIXED_POINT
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#ifdef HAVE_STDINT_H
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#include <stdint.h>
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typedef int16_t blipper_sample_t;
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typedef int32_t blipper_long_sample_t;
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#else
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#if SHRT_MAX == 0x7fff
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typedef short blipper_sample_t;
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#elif INT_MAX == 0x7fff
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typedef int blipper_sample_t;
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#else
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#error "Cannot find suitable type for blipper_sampler_t."
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#endif
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#if INT_MAX == 0x7fffffffl
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typedef int blipper_long_sample_t;
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#elif LONG_MAX == 0x7fffffffl
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typedef long blipper_long_sample_t;
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#else
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#error "Cannot find suitable type for blipper_long_sample_t."
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#endif
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#endif
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#else
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typedef BLIPPER_REAL_T blipper_sample_t;
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typedef BLIPPER_REAL_T blipper_long_sample_t; /* Meaningless for float version. */
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#endif
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/* Create a new blipper.
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* taps: Number of filter taps per impulse.
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*
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* cutoff: Cutoff frequency in the passband. Has a range of [0, 1].
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*
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* beta: Beta used for Kaiser window.
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*
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* decimation: Sets decimation rate.
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* The input sampling rate is then output_rate * decimation.
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* buffer_samples: The maximum number of processed output samples that can be
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* buffered up by blipper.
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*
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* filter_bank: An optional filter which has already been created by
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* blipper_create_filter_bank(). blipper_new() does not take ownership
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* of the buffer and must be freed by caller.
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* If non-NULL, cutoff and beta will be ignored.
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*
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* Some sane values:
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* taps = 64, cutoff = 0.85, beta = 8.0
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*/
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#define blipper_new BLIPPER_MANGLE(blipper_new)
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blipper_t *blipper_new(unsigned taps, double cutoff, double beta,
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unsigned decimation, unsigned buffer_samples, const blipper_sample_t *filter_bank);
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/* Reset the blipper to its initiate state. */
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#define blipper_reset BLIPPER_MANGLE(blipper_reset)
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void blipper_reset(blipper_t *blip);
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/* Create a filter which can be passed to blipper_new() in filter_bank.
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* Arguments to decimation and taps must match. */
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#define blipper_create_filter_bank BLIPPER_MANGLE(blipper_create_filter_bank)
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blipper_sample_t *blipper_create_filter_bank(unsigned decimation,
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unsigned taps, double cutoff, double beta);
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/* Frees the blipper. blip can be NULL (no-op). */
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#define blipper_free BLIPPER_MANGLE(blipper_free)
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void blipper_free(blipper_t *blip);
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/* Add a ramp to the synthesized wave. The ramp is added to the integrator
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* on every input sample.
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* The amount added is delta / clocks per input sample.
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* The interface is fractional to have better accuract with fixed point.
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* This can be combined with a delta train to synthesize e.g. sawtooth waves.
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* When using a ramp, care must be taken to ensure that the integrator does not saturate.
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* It is recommended to use floating point implementation when using the ramp. */
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#define blipper_set_ramp BLIPPER_MANGLE(blipper_set_ramp)
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void blipper_set_ramp(blipper_t *blip, blipper_long_sample_t delta,
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unsigned clocks);
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/* Data pushing interfaces. One of these should be used exclusively. */
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/* Push a single delta, which occurs clock_step input samples after the
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* last time a delta was pushed. The delta value is the difference signal
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* between the new sample and the previous.
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* It is unnecessary to pass a delta of 0.
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* If the deltas are known beforehand (e.g. when synthesizing a waveform),
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* this is a more efficient interface than blipper_push_samples().
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*
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* The caller must ensure not to push deltas in a way that can destabilize
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* the final integration.
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*/
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#define blipper_push_delta BLIPPER_MANGLE(blipper_push_delta)
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void blipper_push_delta(blipper_t *blip, blipper_long_sample_t delta, unsigned clocks_step);
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/* Push raw samples. blipper will find the deltas themself and push them.
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* stride is the number of samples between each sample to be used.
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* This can be used to push interleaved stereo data to two independent
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* blippers.
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*/
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#define blipper_push_samples BLIPPER_MANGLE(blipper_push_samples)
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void blipper_push_samples(blipper_t *blip, const blipper_sample_t *delta,
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unsigned samples, unsigned stride, unsigned clocks_step);
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#define blipper_push_long_samples BLIPPER_MANGLE(blipper_push_long_samples)
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void blipper_push_long_samples(blipper_t *blip, const blipper_long_sample_t *delta,
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unsigned samples, unsigned stride, unsigned clocks_step);
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/* Returns the number of samples available for reading using
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* blipper_read().
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*/
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#define blipper_read_avail BLIPPER_MANGLE(blipper_read_avail)
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unsigned blipper_read_avail(blipper_t *blip);
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/* Returns the current filter phase
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*/
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#define blipper_read_phase BLIPPER_MANGLE(blipper_read_phase)
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unsigned blipper_read_phase(blipper_t *blip);
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/* Reads processed samples. The caller must ensure to not read
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* more than what is returned from blipper_read_avail().
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* As in blipper_push_samples(), stride is the number of samples
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* between each output sample in output.
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* Can be used to write to an interleaved stereo buffer.
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*/
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#define blipper_read BLIPPER_MANGLE(blipper_read)
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void blipper_read(blipper_t *blip, blipper_sample_t *output, unsigned samples,
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unsigned stride);
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#define blipper_read_long BLIPPER_MANGLE(blipper_long_read)
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void blipper_read_long(blipper_t *blip, blipper_long_sample_t *output, unsigned samples,
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unsigned stride);
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#ifdef __cplusplus
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}
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#endif
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#endif
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