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/*
* ddksample_audio.c - OSS DDK sample driver - misc routines
*
* Description:
* This file contains routines that are not related with the
* OSS DDK interface. To understand how OSS DDK works you don't need to
* pay any attention on these routines. They are here just to produce
* some data for the mixer routines (ddksample_mixer.c).
*
* ddksample_misc.c emulates some arbitrary audio device. It does
* volume scaling to the output data and computes the peak meters from the
* result of the scaling.
*/
/*
*
* This file is part of Open Sound System.
*
* Copyright (C) 4Front Technologies 1996-2008.
*
* This this source file is released under GPL v2 license (no other versions).
* See the COPYING file included in the main directory of this source
* distribution for the license terms and conditions.
*
*/
/*
* Solaris DDI includes
*/
#include <sys/types.h>
#include <sys/modctl.h>
#include <sys/kmem.h>
#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
/*
* OSS specific includes
*/
#include <sys/soundcard.h>
#include <sys/ossddk/ossddk.h>
#include "ddksample.h"
/**************************************************/
void
ddksample_do_math (ddksample_portc * portc, void *buf, int len)
{
int i;
ddksample_devc *devc = ossddk_adev_get_devc (portc->dev);
switch (portc->bits + portc->channels)
{
case 16 + 1: /* 16 bits / mono */
{
int val;
int peak = 0;
short *p = buf;
len /= sizeof (*p);
for (i = 0; i < len; i++)
{
/* Do volume computations */
val = *p++ << 8; /* Scale up to 24 bits */
val = (val * portc->left_volume) / DDKSAMPLE_MAX_VOL;
/*
* Note that legacy mixer volume max is always
* 100.
*/
val = (val * devc->mainvol_left) / 100;
/*
* Now we have the sample value after volume control.
* This driver doesn't store this value anywhere but
* if necessary this functionality can be added here.
/*
* Next compute the peak value
*/
if (val < 0)
val = -val; /* Absolute value */
if (val > peak)
peak = val;
}
if (peak > portc->left_peak)
portc->left_peak = peak;
if (peak > portc->right_peak)
portc->right_peak = peak;
}
break;
case 16 + 2: /* 16 bits / stereo */
{
int val;
int left_peak = 0, right_peak = 0;
short *p = buf;
len /= sizeof (*p);
for (i = 0; i < len; i += 2) /* Each stereo sa,ple pair */
{
/*
* Left channel
*/
/* Do volume computations */
val = (*p++) << 8; /* Scale up to 24 bits */
val = (val * portc->left_volume) / DDKSAMPLE_MAX_VOL;
/*
* Note that legacy mixer volume max is always
* 100.
*/
val = (val * devc->mainvol_left) / 100;
/*
* Now we have the sample value after volume control.
* This driver doesn't store this value anywhere but
* if necessary this functionality can be added here.
/*
* Next compute the peak value
*/
if (val < 0)
val = -val; /* Absolute value */
if (val > left_peak)
left_peak = val;
/*
* Right channel
*/
/* Do volume computations */
val = (*p++) << 8; /* Scale up to 24 bits */
val = (val * portc->left_volume) / DDKSAMPLE_MAX_VOL;
/*
* Note that legacy mixer volume max is always
* 100.
*/
val = (val * devc->mainvol_left) / 100;
/*
* Now we have the sample value after volume control.
* This driver doesn't store this value anywhere but
* if necessary this functionality can be added here.
/*
* Next compute the peak value
*/
if (val < 0)
val = -val; /* Absolute value */
if (val > right_peak)
right_peak = val;
}
if (left_peak > portc->left_peak)
portc->left_peak = left_peak;
if (right_peak > portc->right_peak)
portc->right_peak = right_peak;
}
break;
}
}
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