media/libstagefright/codecs/aacdec/inv_short_complex_rot.cpp - third_party/android/platform/frameworks/av - Git at Google

 /* ------------------------------------------------------------------
  * Copyright (C) 1998-2009 PacketVideo
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
  * express or implied.
  * See the License for the specific language governing permissions
  * and limitations under the License.
  * -------------------------------------------------------------------
  */
 /*

  Pathname: inv_short_complex_rot.c
  Funtions:  inv_short_complex_rot

 ------------------------------------------------------------------------------
  REVISION HISTORY

  Date: 10/18/2002
  Description:
             (1) Change the input argument, only a single max is passed.
             (2) Eliminate search for max, a fixed shift has replaced the
                 search for max with minimal loss of precision.
             (3) Eliminated unused variables

  Date: 10/28/2002
  Description:
             (1) Added comments per code review
             (2) Eliminated hardly used condition on if-else (exp==0)

  Description:

  ------------------------------------------------------------------------------
  INPUT AND OUTPUT DEFINITIONS

  Inputs:

     Data_in   = Input vector (sized for short windows
                 2*INV_SHORT_CX_ROT_LENGTH elements), with time domain samples
                 type Int32 *

     Data_out  = Output vector with a post-rotation by exp(j(2pi/N)(k+1/8)),
                 (sized for short windows 2*INV_SHORT_CX_ROT_LENGTH)
                 type Int32 *

     max       = Input, carries the maximum value of the input vector
                 "Data_in"
                 type Int32


  Local Stores/Buffers/Pointers Needed:
     None

  Global Stores/Buffers/Pointers Needed:
     None

  Outputs:
     exp = shift factor to reflect signal scaling

  Pointers and Buffers Modified:
     Results are return in "Data_out"

  Local Stores Modified:
     None

  Global Stores Modified:
     None
 ------------------------------------------------------------------------------
  FUNCTION DESCRIPTION

     inv_short_complex_rot() performs the complex rotation for the inverse MDCT
     for the case of short windows. It performs digit reverse ordering as well
     word normalization to ensure 16 by 16 bit multiplications.

 ------------------------------------------------------------------------------
  REQUIREMENTS

     inv_short_complex_rot() should execute a post-rotation by
     exp( j(2pi/N)(k+1/8)), digit reverse ordering and word normalization

 ------------------------------------------------------------------------------
  REFERENCES

 ------------------------------------------------------------------------------
  RESOURCES USED
    When the code is written for a specific target processor the
      the resources used should be documented below.

  STACK USAGE: [stack count for this module] + [variable to represent
           stack usage for each subroutine called]

      where: [stack usage variable] = stack usage for [subroutine
          name] (see [filename].ext)

  DATA MEMORY USED: x words

  PROGRAM MEMORY USED: x words

  CLOCK CYCLES: [cycle count equation for this module] + [variable
            used to represent cycle count for each subroutine
            called]

      where: [cycle count variable] = cycle count for [subroutine
         name] (see [filename].ext)

 ------------------------------------------------------------------------------
 */


 /*----------------------------------------------------------------------------
 ; INCLUDES
 ----------------------------------------------------------------------------*/

 #include "digit_reversal_tables.h"
 #include "imdct_fxp.h"
 #include "inv_short_complex_rot.h"
 #include "pv_normalize.h"
 #include "fxp_mul32.h"


 /*----------------------------------------------------------------------------
 ; MACROS
 ; Define module specific macros here
 ----------------------------------------------------------------------------*/

 /*----------------------------------------------------------------------------
 ; DEFINES
 ; Include all pre-processor statements here. Include conditional
 ; compile variables also.
 ----------------------------------------------------------------------------*/

 /*----------------------------------------------------------------------------
 ; LOCAL FUNCTION DEFINITIONS
 ; Function Prototype declaration
 ----------------------------------------------------------------------------*/

 /*----------------------------------------------------------------------------
 ; LOCAL VARIABLE DEFINITIONS
 ; Variable declaration - defined here and used outside this module
 ----------------------------------------------------------------------------*/

 /*----------------------------------------------------------------------------
 ; EXTERNAL FUNCTION REFERENCES
 ; Declare functions defined elsewhere and referenced in this module
 ----------------------------------------------------------------------------*/

 /*----------------------------------------------------------------------------
 ; EXTERNAL VARIABLES REFERENCES
 ; Declare variables used in this module but defined elsewhere
 ----------------------------------------------------------------------------*/


 Int inv_short_complex_rot(
     Int32 *Data_in,
     Int32 *Data_out,
     Int32  max)

 {
     Int     i;
     Int16     I;
     const   Int16 *pTable;
     const   Int32 *p_rotate;

     Int32   *pData_in_1;
     Int     exp;
     Int32   temp_re;
     Int32   temp_im;

     Int32   exp_jw;
     Int16   *pData_re;
     Int16   *pData_im;
     Int32   *pData_in_ref;

     Int16   temp_re_0;
     Int16   temp_im_0;
     Int16   temp_re_1;
     Int16   temp_im_1;
     Int16   *p_data_1;
     Int16   *p_data_2;
     Int16   *p_Data_Int_precision;
     Int16   *p_Data_Int_precision_1;
     Int16   *p_Data_Int_precision_2;

     Int     n     = 256;
     Int     n_2   = n >> 1;
     Int     n_4   = n >> 2;
     Int     n_8   = n >> 3;
     Int     n_3_4 = n_2 + n_4;


     p_data_1 = (Int16 *)Data_out;
     p_data_1 += n;
     pData_re  = p_data_1;
     pData_im  = p_data_1 + n_4;


     p_rotate  =  exp_rotation_N_256;
     pTable    =  digit_reverse_64;

     pData_in_ref  =  Data_in;

     exp = 16 - pv_normalize(max);


     if (exp < 0)
     {
         exp = 0;
     }

     exp -= 1;

     for (i = INV_SHORT_CX_ROT_LENGTH; i != 0; i--)
     {

         /*
          * cos_n + j*sin_n == exp(j(2pi/N)(k+1/8))
          */

         /*
          *   Perform digit reversal by accessing index I from table
          */

         I = *pTable++;
         pData_in_1 = pData_in_ref + I;
         /*
          *  Use auxiliary variables to avoid double accesses to memory.
          *  Data in is scaled to use only lower 16 bits.
          */

         temp_im =  *(pData_in_1++);
         temp_re =  *(pData_in_1);

         exp_jw = *p_rotate++;

         /*
          *   Post-rotation
          */

         *(pData_re++)  = (Int16)(cmplx_mul32_by_16(temp_re, -temp_im, exp_jw) >> exp);
         *(pData_im++)  = (Int16)(cmplx_mul32_by_16(temp_im,  temp_re, exp_jw) >> exp);
     }


     p_data_2 = pData_im -  1;


     p_Data_Int_precision = (Int16 *)Data_out;
     p_Data_Int_precision_1 = p_Data_Int_precision + n_3_4 - 1;
     p_Data_Int_precision_2 = p_Data_Int_precision + n_3_4;

     for (i = n_8 >> 1; i != 0; i--)
     {
         temp_re_0 = (*(p_data_1++));
         temp_re_1 = (*(p_data_1++));
         temp_im_0 = (*(p_data_2--));
         temp_im_1 = (*(p_data_2--));

         *(p_Data_Int_precision_1--) =  temp_re_0;
         *(p_Data_Int_precision_1--) =  temp_im_0;
         *(p_Data_Int_precision_1--) =  temp_re_1;
         *(p_Data_Int_precision_1--) =  temp_im_1;

         *(p_Data_Int_precision_2++) =  temp_re_0;
         *(p_Data_Int_precision_2++) =  temp_im_0;
         *(p_Data_Int_precision_2++) =  temp_re_1;
         *(p_Data_Int_precision_2++) =  temp_im_1;

     }


     /*
      *  loop is split to avoid conditional testing inside loop
      */

     p_Data_Int_precision_2 = p_Data_Int_precision;

     for (i = n_8 >> 1; i != 0; i--)
     {

         temp_re_0 = (*(p_data_1++));
         temp_re_1 = (*(p_data_1++));
         temp_im_0 = (*(p_data_2--));
         temp_im_1 = (*(p_data_2--));

         *(p_Data_Int_precision_1--) =   temp_re_0;
         *(p_Data_Int_precision_1--) =   temp_im_0;
         *(p_Data_Int_precision_1--) =   temp_re_1;
         *(p_Data_Int_precision_1--) =   temp_im_1;

         *(p_Data_Int_precision_2++) = (Int16)(-temp_re_0);
         *(p_Data_Int_precision_2++) = (Int16)(-temp_im_0);
         *(p_Data_Int_precision_2++) = (Int16)(-temp_re_1);
         *(p_Data_Int_precision_2++) = (Int16)(-temp_im_1);

     }

     return (exp + 1);
 }
	/* ------------------------------------------------------------------
	* Copyright (C) 1998-2009 PacketVideo
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
	* express or implied.
	* See the License for the specific language governing permissions
	* and limitations under the License.
	* -------------------------------------------------------------------
	*/
	/*

	Pathname: inv_short_complex_rot.c
	Funtions: inv_short_complex_rot

	------------------------------------------------------------------------------
	REVISION HISTORY

	Date: 10/18/2002
	Description:
	(1) Change the input argument, only a single max is passed.
	(2) Eliminate search for max, a fixed shift has replaced the
	search for max with minimal loss of precision.
	(3) Eliminated unused variables

	Date: 10/28/2002
	Description:
	(1) Added comments per code review
	(2) Eliminated hardly used condition on if-else (exp==0)

	Description:

	------------------------------------------------------------------------------
	INPUT AND OUTPUT DEFINITIONS

	Inputs:

	Data_in = Input vector (sized for short windows
	2*INV_SHORT_CX_ROT_LENGTH elements), with time domain samples
	type Int32 *

	Data_out = Output vector with a post-rotation by exp(j(2pi/N)(k+1/8)),
	(sized for short windows 2*INV_SHORT_CX_ROT_LENGTH)
	type Int32 *

	max = Input, carries the maximum value of the input vector
	"Data_in"
	type Int32


	Local Stores/Buffers/Pointers Needed:
	None

	Global Stores/Buffers/Pointers Needed:
	None

	Outputs:
	exp = shift factor to reflect signal scaling

	Pointers and Buffers Modified:
	Results are return in "Data_out"

	Local Stores Modified:
	None

	Global Stores Modified:
	None
	------------------------------------------------------------------------------
	FUNCTION DESCRIPTION

	inv_short_complex_rot() performs the complex rotation for the inverse MDCT
	for the case of short windows. It performs digit reverse ordering as well
	word normalization to ensure 16 by 16 bit multiplications.

	------------------------------------------------------------------------------
	REQUIREMENTS

	inv_short_complex_rot() should execute a post-rotation by
	exp( j(2pi/N)(k+1/8)), digit reverse ordering and word normalization

	------------------------------------------------------------------------------
	REFERENCES

	------------------------------------------------------------------------------
	RESOURCES USED
	When the code is written for a specific target processor the
	the resources used should be documented below.

	STACK USAGE: [stack count for this module] + [variable to represent
	stack usage for each subroutine called]

	where: [stack usage variable] = stack usage for [subroutine
	name] (see [filename].ext)

	DATA MEMORY USED: x words

	PROGRAM MEMORY USED: x words

	CLOCK CYCLES: [cycle count equation for this module] + [variable
	used to represent cycle count for each subroutine
	called]

	where: [cycle count variable] = cycle count for [subroutine
	name] (see [filename].ext)

	------------------------------------------------------------------------------
	*/


	/*----------------------------------------------------------------------------
	; INCLUDES
	----------------------------------------------------------------------------*/

	#include "digit_reversal_tables.h"
	#include "imdct_fxp.h"
	#include "inv_short_complex_rot.h"
	#include "pv_normalize.h"
	#include "fxp_mul32.h"


	/*----------------------------------------------------------------------------
	; MACROS
	; Define module specific macros here
	----------------------------------------------------------------------------*/

	/*----------------------------------------------------------------------------
	; DEFINES
	; Include all pre-processor statements here. Include conditional
	; compile variables also.
	----------------------------------------------------------------------------*/

	/*----------------------------------------------------------------------------
	; LOCAL FUNCTION DEFINITIONS
	; Function Prototype declaration
	----------------------------------------------------------------------------*/

	/*----------------------------------------------------------------------------
	; LOCAL VARIABLE DEFINITIONS
	; Variable declaration - defined here and used outside this module
	----------------------------------------------------------------------------*/

	/*----------------------------------------------------------------------------
	; EXTERNAL FUNCTION REFERENCES
	; Declare functions defined elsewhere and referenced in this module
	----------------------------------------------------------------------------*/

	/*----------------------------------------------------------------------------
	; EXTERNAL VARIABLES REFERENCES
	; Declare variables used in this module but defined elsewhere
	----------------------------------------------------------------------------*/


	Int inv_short_complex_rot(
	Int32 *Data_in,
	Int32 *Data_out,
	Int32 max)

	{
	Int i;
	Int16 I;
	const Int16 *pTable;
	const Int32 *p_rotate;

	Int32 *pData_in_1;
	Int exp;
	Int32 temp_re;
	Int32 temp_im;

	Int32 exp_jw;
	Int16 *pData_re;
	Int16 *pData_im;
	Int32 *pData_in_ref;

	Int16 temp_re_0;
	Int16 temp_im_0;
	Int16 temp_re_1;
	Int16 temp_im_1;
	Int16 *p_data_1;
	Int16 *p_data_2;
	Int16 *p_Data_Int_precision;
	Int16 *p_Data_Int_precision_1;
	Int16 *p_Data_Int_precision_2;

	Int n = 256;
	Int n_2 = n >> 1;
	Int n_4 = n >> 2;
	Int n_8 = n >> 3;
	Int n_3_4 = n_2 + n_4;


	p_data_1 = (Int16 *)Data_out;
	p_data_1 += n;
	pData_re = p_data_1;
	pData_im = p_data_1 + n_4;


	p_rotate = exp_rotation_N_256;
	pTable = digit_reverse_64;

	pData_in_ref = Data_in;

	exp = 16 - pv_normalize(max);


	if (exp < 0)
	{
	exp = 0;
	}

	exp -= 1;

	for (i = INV_SHORT_CX_ROT_LENGTH; i != 0; i--)
	{

	/*
	* cos_n + j*sin_n == exp(j(2pi/N)(k+1/8))
	*/

	/*
	* Perform digit reversal by accessing index I from table
	*/

	I = *pTable++;
	pData_in_1 = pData_in_ref + I;
	/*
	* Use auxiliary variables to avoid double accesses to memory.
	* Data in is scaled to use only lower 16 bits.
	*/

	temp_im = *(pData_in_1++);
	temp_re = *(pData_in_1);

	exp_jw = *p_rotate++;

	/*
	* Post-rotation
	*/

	*(pData_re++) = (Int16)(cmplx_mul32_by_16(temp_re, -temp_im, exp_jw) >> exp);
	*(pData_im++) = (Int16)(cmplx_mul32_by_16(temp_im, temp_re, exp_jw) >> exp);
	}


	p_data_2 = pData_im - 1;


	p_Data_Int_precision = (Int16 *)Data_out;
	p_Data_Int_precision_1 = p_Data_Int_precision + n_3_4 - 1;
	p_Data_Int_precision_2 = p_Data_Int_precision + n_3_4;

	for (i = n_8 >> 1; i != 0; i--)
	{
	temp_re_0 = (*(p_data_1++));
	temp_re_1 = (*(p_data_1++));
	temp_im_0 = (*(p_data_2--));
	temp_im_1 = (*(p_data_2--));

	*(p_Data_Int_precision_1--) = temp_re_0;
	*(p_Data_Int_precision_1--) = temp_im_0;
	*(p_Data_Int_precision_1--) = temp_re_1;
	*(p_Data_Int_precision_1--) = temp_im_1;

	*(p_Data_Int_precision_2++) = temp_re_0;
	*(p_Data_Int_precision_2++) = temp_im_0;
	*(p_Data_Int_precision_2++) = temp_re_1;
	*(p_Data_Int_precision_2++) = temp_im_1;

	}


	/*
	* loop is split to avoid conditional testing inside loop
	*/

	p_Data_Int_precision_2 = p_Data_Int_precision;

	for (i = n_8 >> 1; i != 0; i--)
	{

	temp_re_0 = (*(p_data_1++));
	temp_re_1 = (*(p_data_1++));
	temp_im_0 = (*(p_data_2--));
	temp_im_1 = (*(p_data_2--));

	*(p_Data_Int_precision_1--) = temp_re_0;
	*(p_Data_Int_precision_1--) = temp_im_0;
	*(p_Data_Int_precision_1--) = temp_re_1;
	*(p_Data_Int_precision_1--) = temp_im_1;

	*(p_Data_Int_precision_2++) = (Int16)(-temp_re_0);
	*(p_Data_Int_precision_2++) = (Int16)(-temp_im_0);
	*(p_Data_Int_precision_2++) = (Int16)(-temp_re_1);
	*(p_Data_Int_precision_2++) = (Int16)(-temp_im_1);

	}

	return (exp + 1);
	}