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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (c) 2011 Michael Sevakis
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "system.h"
#include "settings.h"
#include "dsp.h"
#include "pcm.h"
#include "pcm_mixer.h"
#include "misc.h"
static int32_t beep_phase; /* Phase of square wave generator */
static uint32_t beep_step; /* Step of square wave generator on each sample */
static uint32_t beep_amplitude; /* Amplitude of square wave generator */
static int beep_count; /* Number of samples remaining to generate */
/* Reserve enough static space for keyclick to fit */
#define BEEP_BUF_COUNT (NATIVE_FREQUENCY / 1000 * KEYCLICK_DURATION)
static uint32_t beep_buf[BEEP_BUF_COUNT] IBSS_ATTR;
/* Actually output samples into beep_buf */
#if defined(CPU_ARM)
static FORCE_INLINE void beep_generate(int count)
{
uint32_t *out = beep_buf;
uint32_t s;
asm volatile (
"1: \n"
"eor %3, %5, %1, asr #31 \n"
"subs %2, %2, #1 \n"
"str %3, [%0], #4 \n"
"add %1, %1, %4 \n"
"bgt 1b \n"
: "+r"(out), "+r"(beep_phase), "+r"(count),
"=&r"(s)
: "r"(beep_step), "r"(beep_amplitude));
}
#elif defined (CPU_COLDFIRE)
static FORCE_INLINE void beep_generate(int count)
{
uint32_t *out = beep_buf;
uint32_t s;
asm volatile (
"1: \n"
"move.l %1, %3 \n"
"add.l %4, %1 \n"
"add.l %3, %3 \n"
"subx.l %3, %3 \n"
"eor.l %5, %3 \n"
"move.l %3, (%0)+ \n"
"subq.l #1, %2 \n"
"bgt.b 1b \n"
: "+a"(out), "+d"(beep_phase), "+d"(count),
"=&d"(s)
: "r"(beep_step), "d"(beep_amplitude));
}
#else
static FORCE_INLINE void beep_generate(int count)
{
uint32_t *out = beep_buf;
uint32_t amplitude = beep_amplitude;
uint32_t step = beep_step;
int32_t phase = beep_phase;
do
{
*out++ = (phase >> 31) ^ amplitude;
phase += step;
}
while (--count > 0);
beep_phase = phase;
}
#endif
/* Callback to generate the beep frames - also don't want inlining of
call below in beep_play */
static void __attribute__((noinline))
beep_get_more(unsigned char **start, size_t *size)
{
int count = beep_count;
if (count > 0)
{
count = MIN(count, BEEP_BUF_COUNT);
beep_count -= count;
*start = (unsigned char *)beep_buf;
*size = count * sizeof(uint32_t);
beep_generate(count);
}
}
/* Generates a constant square wave sound with a given frequency in Hertz for
a duration in milliseconds */
void beep_play(unsigned int frequency, unsigned int duration,
unsigned int amplitude)
{
mixer_channel_stop(PCM_MIXER_CHAN_BEEP);
if (frequency == 0 || duration == 0 || amplitude == 0)
return;
if (amplitude > INT16_MAX)
amplitude = INT16_MAX;
/* Setup the parameters for the square wave generator */
beep_phase = 0;
beep_step = 0xffffffffu / NATIVE_FREQUENCY * frequency;
beep_count = NATIVE_FREQUENCY / 1000 * duration;
beep_amplitude = amplitude | (amplitude << 16); /* Word:|AMP16|AMP16| */
/* If it fits - avoid cb overhead */
unsigned char *start;
size_t size;
/* Generate first frame here */
beep_get_more(&start, &size);
mixer_channel_set_amplitude(PCM_MIXER_CHAN_BEEP, MIX_AMP_UNITY);
mixer_channel_play_data(PCM_MIXER_CHAN_BEEP,
beep_count ? beep_get_more : NULL,
start, size);
}
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