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