pvmp3_dct_6.cpp
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/* ------------------------------------------------------------------
* 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.
* -------------------------------------------------------------------
*/
/*
------------------------------------------------------------------------------
PacketVideo Corp.
MP3 Decoder Library
Filename: pvmp3_dct6.cpp
Date: 09/21/2007
------------------------------------------------------------------------------
REVISION HISTORY
Description:
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Input
Int32 vec[] vector of 6 32-bit integers
Returns
Int32 vec[] dct computation in-place
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
Returns the dct of length 6 of the input vector
------------------------------------------------------------------------------
REQUIREMENTS
------------------------------------------------------------------------------
REFERENCES
------------------------------------------------------------------------------
PSEUDO-CODE
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "pvmp3_audio_type_defs.h"
#include "pv_mp3dec_fxd_op.h"
#include "pvmp3_mdct_6.h"
/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/
#define Qfmt30(a) (Int32)(a*((Int32)1<<30) + (a>=0?0.5F:-0.5F))
#define cos_pi_6 Qfmt30( 0.86602540378444f)
#define cos_2_pi_6 Qfmt30( 0.5f)
#define cos_7_pi_12 Qfmt30( -0.25881904510252f)
#define cos_3_pi_12 Qfmt30( 0.70710678118655f)
#define cos_11_pi_12 Qfmt30( -0.96592582628907f)
/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; Function Prototype declaration
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL STORE/BUFFER/POINTER DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; EXTERNAL FUNCTION REFERENCES
; Declare functions defined elsewhere and referenced in this module
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
; Declare variables used in this module but defined elsewhere
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; FUNCTION CODE
----------------------------------------------------------------------------*/
void pvmp3_dct_6(int32 vec[])
{
Int32 tmp0;
Int32 tmp1;
Int32 tmp2;
Int32 tmp3;
Int32 tmp4;
Int32 tmp5;
/* split input vector */
tmp0 = vec[5] + vec[0];
tmp5 = vec[5] - vec[0];
tmp1 = vec[4] + vec[1];
tmp4 = vec[4] - vec[1];
tmp2 = vec[3] + vec[2];
tmp3 = vec[3] - vec[2];
vec[0] = tmp0 + tmp2 ;
vec[2] = fxp_mul32_Q30(tmp0 - tmp2, cos_pi_6);
vec[4] = (vec[0] >> 1) - tmp1;
vec[0] += tmp1;
tmp0 = fxp_mul32_Q30(tmp3, cos_7_pi_12);
tmp0 = fxp_mac32_Q30(tmp4, -cos_3_pi_12, tmp0);
vec[1] = fxp_mac32_Q30(tmp5, cos_11_pi_12, tmp0);
vec[3] = fxp_mul32_Q30((tmp3 + tmp4 - tmp5), cos_3_pi_12);
tmp0 = fxp_mul32_Q30(tmp3, cos_11_pi_12);
tmp0 = fxp_mac32_Q30(tmp4, cos_3_pi_12, tmp0);
vec[5] = fxp_mac32_Q30(tmp5, cos_7_pi_12, tmp0);
}