12c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* 22c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * Copyright (C) 2004-2010 NXP Software 32c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * Copyright (C) 2010 The Android Open Source Project 42c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * 52c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * Licensed under the Apache License, Version 2.0 (the "License"); 62c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * you may not use this file except in compliance with the License. 72c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * You may obtain a copy of the License at 82c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * 92c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * http://www.apache.org/licenses/LICENSE-2.0 102c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * 112c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * Unless required by applicable law or agreed to in writing, software 122c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * distributed under the License is distributed on an "AS IS" BASIS, 132c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 142c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * See the License for the specific language governing permissions and 152c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent * limitations under the License. 162c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent */ 172c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 182c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent#include "LVM_Types.h" 192c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent#include "LVM_Macros.h" 202c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent#include "LVC_Mixer_Private.h" 212c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 222c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/************************************************************************/ 232c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* FUNCTION: */ 242c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* LVMixer3_SetTarget */ 252c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* */ 262c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* DESCRIPTION: */ 272c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* This function updates the private instance parameters: Shift,Target,*/ 282c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* Current for a given Audio Stream based on new value of TargetGain */ 292c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* */ 302c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* This function caclulates the "Shift" required to provide the */ 312c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* integer part of TargetGain and fractional gain values "Target" and */ 322c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* "Current" based on maximum(TargetGain,CurrentGain) */ 332c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* E.g. CurrentGain=1.9 and TargetGain=2.5 then based on */ 342c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* MaxGain of 2.5, Shift = 2, Current=1.9/4=0.475, Target=2.5/4=0.625 */ 352c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* Therefore integer gain of 4 is provided by Left Shift of 2 and */ 362c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* fraction gain is provided through Current=0.475 and Target=0.625 */ 372c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* PARAMETERS: */ 382c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* pStream - ptr to Instance Parameter Structure LVMixer3_st */ 392c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* for an Audio Stream */ 402c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* TargetGain - TargetGain value in Q 16.15 format */ 412c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* */ 422c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* RETURNS: */ 432c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* void */ 442c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/* */ 452c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent/************************************************************************/ 462c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 472c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurentvoid LVC_Mixer_SetTarget(LVMixer3_st *pStream, 482c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent LVM_INT32 TargetGain) 492c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent{ 502c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent LVM_INT32 Shift=0; 512c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent LVM_INT32 CurrentGain; 522c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent LVM_INT32 MaxGain=TargetGain; // MaxGain is in Q16.15 format 532c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent Mix_Private_st *pInstance=(Mix_Private_st *)pStream->PrivateParams; 542c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent CurrentGain=pInstance->Current>>(16-pInstance->Shift); // CurrentGain in Q16.15 format 552c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent if(CurrentGain>MaxGain) 562c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent MaxGain=CurrentGain; // MaxGain=max(CurrentGain,TargetGain) 572c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent 582c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent MaxGain=MaxGain>>15; // MaxGain in Q31.0 format i.e Integer part only 592c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent while(MaxGain>0){ // Update Shift required to provide integer gain 602c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent Shift++; 612c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent MaxGain=MaxGain>>1; 622c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent } 632c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent pInstance->Target=TargetGain<<(16-Shift); // Update fractional gain Target 642c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent pInstance->Current=CurrentGain<<(16-Shift); // Update fractional gain Current 652c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent pInstance->Shift=Shift; // Update Shift 662c8e5cab3faa6d360e222b7a6c40a80083d021acEric Laurent} 67