/*
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* Analogy for Linux, test program for waveform generation
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*
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* Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
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* Copyright (C) 2008 Alexis Berlemont <alexis.berlemont@free.fr>
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*
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* Xenomai is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* Xenomai is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Xenomai; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <errno.h>
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#include <math.h>
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#include "wf_facilities.h"
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#ifndef PI
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#define PI 3.14159265358979323846
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#endif
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void a4l_wf_init_sine(struct waveform_config *config, double *values)
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{
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int i;
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double ratio = config->wf_frequency / config->spl_frequency;
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for (i = 0; i < config->spl_count; i++) {
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values[i] = config->wf_offset -
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config->wf_amplitude / 2 +
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0.5 * config->wf_amplitude * cos(i * 2 * PI * ratio);
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}
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}
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void a4l_wf_init_sawtooth(struct waveform_config *config, double *values)
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{
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int i;
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double ratio = config->wf_frequency / config->spl_frequency;
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for (i = 0; i < config->spl_count; i++) {
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int period_idx = (int)floor(i * ratio);
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values[i] = config->wf_offset -
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config->wf_amplitude / 2 -
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period_idx * config->wf_amplitude +
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i * ratio * config->wf_amplitude;
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}
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}
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void a4l_wf_init_triangular(struct waveform_config *config, double *values)
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{
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int i;
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double ratio = config->wf_frequency / config->spl_frequency;
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for (i = 0; i < config->spl_count; i++) {
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int period_idx = (int)floor(i * ratio);
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int half_period_idx = (int)floor(i * 2 * ratio);
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int rise = ((half_period_idx % 2) == 0) ? 1 : 0;
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if (rise) {
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values[i] = config->wf_offset -
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config->wf_amplitude / 2 -
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2 * period_idx * config->wf_amplitude +
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2 * i * ratio * config->wf_amplitude;
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} else {
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values[i] = config->wf_offset -
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config->wf_amplitude / 2 +
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2 * (period_idx + 1) * config->wf_amplitude -
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2 * i * ratio * config->wf_amplitude;
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}
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}
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}
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void a4l_wf_init_steps(struct waveform_config *config, double *values)
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{
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int i;
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double ratio = config->wf_frequency / config->spl_frequency;
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for (i = 0; i < config->spl_count; i++) {
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int half_period_idx = (int)floor(i * 2 * ratio);
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int even = (half_period_idx % 2 == 0);
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values[i] = config->wf_offset -
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config->wf_amplitude / 2 + even * config->wf_amplitude;
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}
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}
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void a4l_wf_set_sample_count(struct waveform_config *config)
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{
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int sample_count = MIN_SAMPLE_COUNT;
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int best_count = MIN_SAMPLE_COUNT;
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double lowest_diff = INFINITY;
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while (sample_count < MAX_SAMPLE_COUNT) {
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double ratio = (double)sample_count *
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(config->wf_frequency / config->spl_frequency);
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int ceiling = ceil(ratio);
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double diff = (double)ceiling - ratio;
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assert(diff >= 0);
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if (diff < lowest_diff) {
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lowest_diff = diff;
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best_count = sample_count;
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}
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if (diff == 0)
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break;
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sample_count++;
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}
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if (lowest_diff != 0) {
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fprintf(stderr,
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"Warning: unable to create a contiguous signal\n");
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fprintf(stderr, "Warning: an approximation is performed\n");
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}
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config->spl_count = best_count;
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}
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int a4l_wf_check_config(struct waveform_config *config)
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{
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if (config->wf_amplitude == 0)
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fprintf(stderr, "Warning: the signal will be constant\n");
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if (config->wf_frequency * 2 > config->spl_frequency) {
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fprintf(stderr,
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"Error: the sampling frequency is not correct\n");
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fprintf(stderr,
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"Error: sampling frequency >= 2 * signal frequency\n");
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return -EINVAL;
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}
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/* TODO: check with find_range */
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return 0;
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}
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static void (* init_values[])(struct waveform_config *, double *) = {
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a4l_wf_init_sine,
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a4l_wf_init_sawtooth,
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a4l_wf_init_triangular,
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a4l_wf_init_steps,
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};
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void a4l_wf_init_values(struct waveform_config *config, double *values)
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{
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init_values[config->wf_kind](config, values);
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}
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void a4l_wf_dump_values(struct waveform_config *config, double *values)
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{
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int i;
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for (i = 0; i < config->spl_count; i++)
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fprintf(stderr, "%f\n", values[i]);
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}
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