/
dct64.c
174 lines (148 loc) · 4.38 KB
/
dct64.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
/*
dct64.c: DCT64, the plain C version
copyright ?-2006 by the mpg123 project - free software under the terms of the LGPL 2.1
see COPYING and AUTHORS files in distribution or http://mpg123.org
initially written by Michael Hipp
*/
/*
* Discrete Cosine Tansform (DCT) for subband synthesis
*
* -funroll-loops (for gcc) will remove the loops for better performance
* using loops in the source-code enhances readabillity
*
*
* TODO: write an optimized version for the down-sampling modes
* (in these modes the bands 16-31 (2:1) or 8-31 (4:1) are zero
*/
#include "mpg123lib_intern.h"
void dct64(real *out0,real *out1,real *samples)
{
real bufs[64];
{
register int i,j;
register real *b1,*b2,*bs,*costab;
b1 = samples;
bs = bufs;
costab = pnts[0]+16;
b2 = b1 + 32;
for(i=15;i>=0;i--)
*bs++ = (*b1++ + *--b2);
for(i=15;i>=0;i--)
*bs++ = REAL_MUL((*--b2 - *b1++), *--costab);
b1 = bufs;
costab = pnts[1]+8;
b2 = b1 + 16;
{
for(i=7;i>=0;i--)
*bs++ = (*b1++ + *--b2);
for(i=7;i>=0;i--)
*bs++ = REAL_MUL((*--b2 - *b1++), *--costab);
b2 += 32;
costab += 8;
for(i=7;i>=0;i--)
*bs++ = (*b1++ + *--b2);
for(i=7;i>=0;i--)
*bs++ = REAL_MUL((*b1++ - *--b2), *--costab);
b2 += 32;
}
bs = bufs;
costab = pnts[2];
b2 = b1 + 8;
for(j=2;j;j--)
{
for(i=3;i>=0;i--)
*bs++ = (*b1++ + *--b2);
for(i=3;i>=0;i--)
*bs++ = REAL_MUL((*--b2 - *b1++), costab[i]);
b2 += 16;
for(i=3;i>=0;i--)
*bs++ = (*b1++ + *--b2);
for(i=3;i>=0;i--)
*bs++ = REAL_MUL((*b1++ - *--b2), costab[i]);
b2 += 16;
}
b1 = bufs;
costab = pnts[3];
b2 = b1 + 4;
for(j=4;j;j--)
{
*bs++ = (*b1++ + *--b2);
*bs++ = (*b1++ + *--b2);
*bs++ = REAL_MUL((*--b2 - *b1++), costab[1]);
*bs++ = REAL_MUL((*--b2 - *b1++), costab[0]);
b2 += 8;
*bs++ = (*b1++ + *--b2);
*bs++ = (*b1++ + *--b2);
*bs++ = REAL_MUL((*b1++ - *--b2), costab[1]);
*bs++ = REAL_MUL((*b1++ - *--b2), costab[0]);
b2 += 8;
}
bs = bufs;
costab = pnts[4];
for(j=8;j;j--)
{
real v0,v1;
v0=*b1++; v1 = *b1++;
*bs++ = (v0 + v1);
*bs++ = REAL_MUL((v0 - v1), (*costab));
v0=*b1++; v1 = *b1++;
*bs++ = (v0 + v1);
*bs++ = REAL_MUL((v1 - v0), (*costab));
}
}
{
register real *b1;
register int i;
for(b1=bufs,i=8;i;i--,b1+=4)
b1[2] += b1[3];
for(b1=bufs,i=4;i;i--,b1+=8)
{
b1[4] += b1[6];
b1[6] += b1[5];
b1[5] += b1[7];
}
for(b1=bufs,i=2;i;i--,b1+=16)
{
b1[8] += b1[12];
b1[12] += b1[10];
b1[10] += b1[14];
b1[14] += b1[9];
b1[9] += b1[13];
b1[13] += b1[11];
b1[11] += b1[15];
}
}
out0[0x10*16] = REAL_SCALE_DCT64(bufs[0]);
out0[0x10*15] = REAL_SCALE_DCT64(bufs[16+0] + bufs[16+8]);
out0[0x10*14] = REAL_SCALE_DCT64(bufs[8]);
out0[0x10*13] = REAL_SCALE_DCT64(bufs[16+8] + bufs[16+4]);
out0[0x10*12] = REAL_SCALE_DCT64(bufs[4]);
out0[0x10*11] = REAL_SCALE_DCT64(bufs[16+4] + bufs[16+12]);
out0[0x10*10] = REAL_SCALE_DCT64(bufs[12]);
out0[0x10* 9] = REAL_SCALE_DCT64(bufs[16+12] + bufs[16+2]);
out0[0x10* 8] = REAL_SCALE_DCT64(bufs[2]);
out0[0x10* 7] = REAL_SCALE_DCT64(bufs[16+2] + bufs[16+10]);
out0[0x10* 6] = REAL_SCALE_DCT64(bufs[10]);
out0[0x10* 5] = REAL_SCALE_DCT64(bufs[16+10] + bufs[16+6]);
out0[0x10* 4] = REAL_SCALE_DCT64(bufs[6]);
out0[0x10* 3] = REAL_SCALE_DCT64(bufs[16+6] + bufs[16+14]);
out0[0x10* 2] = REAL_SCALE_DCT64(bufs[14]);
out0[0x10* 1] = REAL_SCALE_DCT64(bufs[16+14] + bufs[16+1]);
out0[0x10* 0] = REAL_SCALE_DCT64(bufs[1]);
out1[0x10* 0] = REAL_SCALE_DCT64(bufs[1]);
out1[0x10* 1] = REAL_SCALE_DCT64(bufs[16+1] + bufs[16+9]);
out1[0x10* 2] = REAL_SCALE_DCT64(bufs[9]);
out1[0x10* 3] = REAL_SCALE_DCT64(bufs[16+9] + bufs[16+5]);
out1[0x10* 4] = REAL_SCALE_DCT64(bufs[5]);
out1[0x10* 5] = REAL_SCALE_DCT64(bufs[16+5] + bufs[16+13]);
out1[0x10* 6] = REAL_SCALE_DCT64(bufs[13]);
out1[0x10* 7] = REAL_SCALE_DCT64(bufs[16+13] + bufs[16+3]);
out1[0x10* 8] = REAL_SCALE_DCT64(bufs[3]);
out1[0x10* 9] = REAL_SCALE_DCT64(bufs[16+3] + bufs[16+11]);
out1[0x10*10] = REAL_SCALE_DCT64(bufs[11]);
out1[0x10*11] = REAL_SCALE_DCT64(bufs[16+11] + bufs[16+7]);
out1[0x10*12] = REAL_SCALE_DCT64(bufs[7]);
out1[0x10*13] = REAL_SCALE_DCT64(bufs[16+7] + bufs[16+15]);
out1[0x10*14] = REAL_SCALE_DCT64(bufs[15]);
out1[0x10*15] = REAL_SCALE_DCT64(bufs[16+15]);
}