1/* ------------------------------------------------------------------
2 * Copyright (C) 1998-2009 PacketVideo
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
13 * express or implied.
14 * See the License for the specific language governing permissions
15 * and limitations under the License.
16 * -------------------------------------------------------------------
17 */
18/*
19------------------------------------------------------------------------------
20
21   PacketVideo Corp.
22   MP3 Decoder Library
23
24   Filename: pvmp3_dct6.cpp
25
26     Date: 09/21/2007
27
28------------------------------------------------------------------------------
29 REVISION HISTORY
30
31
32 Description:
33
34------------------------------------------------------------------------------
35 INPUT AND OUTPUT DEFINITIONS
36
37Input
38    Int32  vec[]             vector of 6  32-bit integers
39Returns
40    Int32  vec[]             dct computation in-place
41
42
43------------------------------------------------------------------------------
44 FUNCTION DESCRIPTION
45
46    Returns the dct of length 6 of the input vector
47
48------------------------------------------------------------------------------
49 REQUIREMENTS
50
51
52------------------------------------------------------------------------------
53 REFERENCES
54
55------------------------------------------------------------------------------
56 PSEUDO-CODE
57
58------------------------------------------------------------------------------
59*/
60
61
62/*----------------------------------------------------------------------------
63; INCLUDES
64----------------------------------------------------------------------------*/
65
66#include "pvmp3_audio_type_defs.h"
67#include "pv_mp3dec_fxd_op.h"
68#include "pvmp3_mdct_6.h"
69
70
71/*----------------------------------------------------------------------------
72; MACROS
73; Define module specific macros here
74----------------------------------------------------------------------------*/
75
76
77/*----------------------------------------------------------------------------
78; DEFINES
79; Include all pre-processor statements here. Include conditional
80; compile variables also.
81----------------------------------------------------------------------------*/
82#define Qfmt30(a)   (Int32)((a)*((Int32)1<<30) + ((a)>=0?0.5F:-0.5F))
83
84#define cos_pi_6     Qfmt30(  0.86602540378444f)
85#define cos_2_pi_6   Qfmt30(  0.5f)
86#define cos_7_pi_12  Qfmt30( -0.25881904510252f)
87#define cos_3_pi_12  Qfmt30(  0.70710678118655f)
88#define cos_11_pi_12 Qfmt30( -0.96592582628907f)
89
90/*----------------------------------------------------------------------------
91; LOCAL FUNCTION DEFINITIONS
92; Function Prototype declaration
93----------------------------------------------------------------------------*/
94
95/*----------------------------------------------------------------------------
96; LOCAL STORE/BUFFER/POINTER DEFINITIONS
97; Variable declaration - defined here and used outside this module
98----------------------------------------------------------------------------*/
99
100/*----------------------------------------------------------------------------
101; EXTERNAL FUNCTION REFERENCES
102; Declare functions defined elsewhere and referenced in this module
103----------------------------------------------------------------------------*/
104
105/*----------------------------------------------------------------------------
106; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
107; Declare variables used in this module but defined elsewhere
108----------------------------------------------------------------------------*/
109
110/*----------------------------------------------------------------------------
111; FUNCTION CODE
112----------------------------------------------------------------------------*/
113
114void pvmp3_dct_6(int32 vec[])
115{
116
117    Int32 tmp0;
118    Int32 tmp1;
119    Int32 tmp2;
120    Int32 tmp3;
121    Int32 tmp4;
122    Int32 tmp5;
123
124
125    /*  split input vector */
126
127    tmp0 =  vec[5] + vec[0];
128    tmp5 =  vec[5] - vec[0];
129    tmp1 =  vec[4] + vec[1];
130    tmp4 =  vec[4] - vec[1];
131    tmp2 =  vec[3] + vec[2];
132    tmp3 =  vec[3] - vec[2];
133
134    vec[0]  = tmp0 + tmp2 ;
135    vec[2]  = fxp_mul32_Q30(tmp0 - tmp2,   cos_pi_6);
136    vec[4]  = (vec[0] >> 1) - tmp1;
137    vec[0] += tmp1;
138
139    tmp0    =  fxp_mul32_Q30(tmp3,  cos_7_pi_12);
140    tmp0    =  fxp_mac32_Q30(tmp4,  -cos_3_pi_12, tmp0);
141    vec[1]  =  fxp_mac32_Q30(tmp5,  cos_11_pi_12, tmp0);
142
143    vec[3]  =  fxp_mul32_Q30((tmp3 + tmp4  - tmp5), cos_3_pi_12);
144    tmp0    =  fxp_mul32_Q30(tmp3, cos_11_pi_12);
145    tmp0    =  fxp_mac32_Q30(tmp4,  cos_3_pi_12, tmp0);
146    vec[5]  =  fxp_mac32_Q30(tmp5,  cos_7_pi_12, tmp0);
147
148}
149
150
151
152
153