sound.c
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/*
* Copyright (C) 2012 Samsung Electronics
* R. Chandrasekar <rcsekar@samsung.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <sound.h>
void sound_create_square_wave(unsigned short *data, int size, uint32_t freq)
{
const int sample = 48000;
const unsigned short amplitude = 16000; /* between 1 and 32767 */
const int period = freq ? sample / freq : 0;
const int half = period / 2;
assert(freq);
/* Make sure we don't overflow our buffer */
if (size % 2)
size--;
while (size) {
int i;
for (i = 0; size && i < half; i++) {
size -= 2;
*data++ = amplitude;
*data++ = amplitude;
}
for (i = 0; size && i < period - half; i++) {
size -= 2;
*data++ = -amplitude;
*data++ = -amplitude;
}
}
}