1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (C) 2012 Samsung Electronics 4 * R. Chandrasekar <rcsekar@samsung.com> 5 */ 6 7 #include <common.h> 8 #include <sound.h> 9 sound_create_square_wave(uint sample_rate,unsigned short * data,int size,uint freq,uint channels)10void sound_create_square_wave(uint sample_rate, unsigned short *data, int size, 11 uint freq, uint channels) 12 { 13 const unsigned short amplitude = 16000; /* between 1 and 32767 */ 14 const int period = freq ? sample_rate / freq : 0; 15 const int half = period / 2; 16 17 assert(freq); 18 19 /* Make sure we don't overflow our buffer */ 20 if (size % 2) 21 size--; 22 23 while (size) { 24 int i, j; 25 26 for (i = 0; size && i < half; i++) { 27 size -= 2; 28 for (j = 0; j < channels; j++) 29 *data++ = amplitude; 30 } 31 for (i = 0; size && i < period - half; i++) { 32 size -= 2; 33 for (j = 0; j < channels; j++) 34 *data++ = -amplitude; 35 } 36 } 37 } 38