104 lines
3.6 KiB
C
104 lines
3.6 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (c) 2011 Michael Sevakis
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "config.h"
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#include "system.h"
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#include "settings.h"
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#include "pcm.h"
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#include "pcm_mixer.h"
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#include "misc.h"
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#include "fixedpoint.h"
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/** Beep generation, CPU optimized **/
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#include "asm/beep.c"
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static uint32_t beep_phase; /* Phase of square wave generator */
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static uint32_t beep_step; /* Step of square wave generator on each sample */
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#ifdef BEEP_GENERIC
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static int16_t beep_amplitude; /* Amplitude of square wave generator */
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#else
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/* Optimized routines do XOR with phase sign bit in both channels at once */
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static uint32_t beep_amplitude; /* Amplitude of square wave generator */
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#endif
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static int beep_count; /* Number of samples remaining to generate */
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#define BEEP_COUNT(fs, duration) ((fs) / 1000 * (duration))
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/* Reserve enough static space for keyclick to fit in worst case */
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#define BEEP_BUF_COUNT BEEP_COUNT(PLAY_SAMPR_MAX, KEYCLICK_DURATION)
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static int16_t beep_buf[BEEP_BUF_COUNT*2] IBSS_ATTR __attribute__((aligned(4)));
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/* Callback to generate the beep frames - also don't want inlining of
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call below in beep_play */
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static void __attribute__((noinline))
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beep_get_more(const void **start, size_t *size)
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{
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int count = beep_count;
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if (count > 0)
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{
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count = MIN(count, BEEP_BUF_COUNT);
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beep_count -= count;
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*start = beep_buf;
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*size = count * 2 * sizeof (int16_t);
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beep_generate((void *)beep_buf, count, &beep_phase,
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beep_step, beep_amplitude);
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}
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}
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/* Generates a constant square wave sound with a given frequency in Hertz for
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a duration in milliseconds */
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void beep_play(unsigned int frequency, unsigned int duration,
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unsigned int amplitude)
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{
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mixer_channel_stop(PCM_MIXER_CHAN_BEEP);
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if (frequency == 0 || duration == 0 || amplitude == 0)
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return;
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if (amplitude > INT16_MAX)
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amplitude = INT16_MAX;
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/* Setup the parameters for the square wave generator */
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uint32_t fout = mixer_get_frequency();
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beep_phase = 0;
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beep_step = fp_div(frequency, fout, 32);
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beep_count = BEEP_COUNT(fout, duration);
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#ifdef BEEP_GENERIC
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beep_amplitude = amplitude;
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#else
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/* Optimized routines do XOR with phase sign bit in both channels at once */
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beep_amplitude = amplitude | (amplitude << 16); /* Word:|AMP16|AMP16| */
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#endif
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/* If it fits - avoid cb overhead */
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const void *start;
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size_t size;
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/* Generate first frame here */
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beep_get_more(&start, &size);
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mixer_channel_set_amplitude(PCM_MIXER_CHAN_BEEP, MIX_AMP_UNITY);
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mixer_channel_play_data(PCM_MIXER_CHAN_BEEP,
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beep_count ? beep_get_more : NULL,
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start, size);
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}
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