4
* Copyright (C) 1991, 1992, Thomas G. Lane.
5
* This file is part of the Independent JPEG Group's software.
6
* For conditions of distribution and use, see the accompanying README file.
8
* This file contains the basic inverse-DCT transformation subroutine.
10
* This implementation is based on an algorithm described in
11
* C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT
12
* Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics,
13
* Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991.
14
* The primary algorithm described there uses 11 multiplies and 29 adds.
15
* We use their alternate method with 12 multiplies and 32 adds.
16
* The advantage of this method is that no data path contains more than one
17
* multiplication; this allows a very simple and accurate implementation in
18
* scaled fixed-point arithmetic, with a minimal number of shifts.
20
* I've made lots of modifications to attempt to take advantage of the
21
* sparse nature of the DCT matrices we're getting. Although the logic
22
* is cumbersome, it's straightforward and the resulting code is much
25
* A better way to do this would be to pass in the DCT block as a sparse
26
* matrix, perhaps with the difference cases encoded.
31
* Independent JPEG Group's LLM idct.
37
#define EIGHT_BIT_SAMPLES
44
#define RIGHT_SHIFT(x, n) ((x) >> (n))
46
typedef DCTELEM DCTBLOCK[DCTSIZE2];
51
* This routine is specialized to the case DCTSIZE = 8.
55
Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
60
* A 2-D IDCT can be done by 1-D IDCT on each row followed by 1-D IDCT
61
* on each column. Direct algorithms are also available, but they are
62
* much more complex and seem not to be any faster when reduced to code.
64
* The poop on this scaling stuff is as follows:
66
* Each 1-D IDCT step produces outputs which are a factor of sqrt(N)
67
* larger than the true IDCT outputs. The final outputs are therefore
68
* a factor of N larger than desired; since N=8 this can be cured by
69
* a simple right shift at the end of the algorithm. The advantage of
70
* this arrangement is that we save two multiplications per 1-D IDCT,
71
* because the y0 and y4 inputs need not be divided by sqrt(N).
73
* We have to do addition and subtraction of the integer inputs, which
74
* is no problem, and multiplication by fractional constants, which is
75
* a problem to do in integer arithmetic. We multiply all the constants
76
* by CONST_SCALE and convert them to integer constants (thus retaining
77
* CONST_BITS bits of precision in the constants). After doing a
78
* multiplication we have to divide the product by CONST_SCALE, with proper
79
* rounding, to produce the correct output. This division can be done
80
* cheaply as a right shift of CONST_BITS bits. We postpone shifting
81
* as long as possible so that partial sums can be added together with
82
* full fractional precision.
84
* The outputs of the first pass are scaled up by PASS1_BITS bits so that
85
* they are represented to better-than-integral precision. These outputs
86
* require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word
87
* with the recommended scaling. (To scale up 12-bit sample data further, an
88
* intermediate int32 array would be needed.)
90
* To avoid overflow of the 32-bit intermediate results in pass 2, we must
91
* have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis
92
* shows that the values given below are the most effective.
95
#ifdef EIGHT_BIT_SAMPLES
98
#define PASS1_BITS 1 /* lose a little precision to avoid overflow */
101
#define ONE ((int32_t) 1)
103
#define CONST_SCALE (ONE << CONST_BITS)
105
/* Convert a positive real constant to an integer scaled by CONST_SCALE.
106
* IMPORTANT: if your compiler doesn't do this arithmetic at compile time,
107
* you will pay a significant penalty in run time. In that case, figure
108
* the correct integer constant values and insert them by hand.
111
/* Actually FIX is no longer used, we precomputed them all */
112
#define FIX(x) ((int32_t) ((x) * CONST_SCALE + 0.5))
114
/* Descale and correctly round an int32_t value that's scaled by N bits.
115
* We assume RIGHT_SHIFT rounds towards minus infinity, so adding
116
* the fudge factor is correct for either sign of X.
119
#define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
121
/* Multiply an int32_t variable by an int32_t constant to yield an int32_t result.
122
* For 8-bit samples with the recommended scaling, all the variable
123
* and constant values involved are no more than 16 bits wide, so a
124
* 16x16->32 bit multiply can be used instead of a full 32x32 multiply;
125
* this provides a useful speedup on many machines.
126
* There is no way to specify a 16x16->32 multiply in portable C, but
127
* some C compilers will do the right thing if you provide the correct
128
* combination of casts.
129
* NB: for 12-bit samples, a full 32-bit multiplication will be needed.
132
#ifdef EIGHT_BIT_SAMPLES
133
#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
134
#define MULTIPLY(var,const) (((int16_t) (var)) * ((int16_t) (const)))
136
#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */
137
#define MULTIPLY(var,const) (((int16_t) (var)) * ((int32_t) (const)))
141
#ifndef MULTIPLY /* default definition */
142
#define MULTIPLY(var,const) ((var) * (const))
147
Unlike our decoder where we approximate the FIXes, we need to use exact
148
ones here or successive P-frames will drift too much with Reference frame coding
150
#define FIX_0_211164243 1730
151
#define FIX_0_275899380 2260
152
#define FIX_0_298631336 2446
153
#define FIX_0_390180644 3196
154
#define FIX_0_509795579 4176
155
#define FIX_0_541196100 4433
156
#define FIX_0_601344887 4926
157
#define FIX_0_765366865 6270
158
#define FIX_0_785694958 6436
159
#define FIX_0_899976223 7373
160
#define FIX_1_061594337 8697
161
#define FIX_1_111140466 9102
162
#define FIX_1_175875602 9633
163
#define FIX_1_306562965 10703
164
#define FIX_1_387039845 11363
165
#define FIX_1_451774981 11893
166
#define FIX_1_501321110 12299
167
#define FIX_1_662939225 13623
168
#define FIX_1_847759065 15137
169
#define FIX_1_961570560 16069
170
#define FIX_2_053119869 16819
171
#define FIX_2_172734803 17799
172
#define FIX_2_562915447 20995
173
#define FIX_3_072711026 25172
176
* Perform the inverse DCT on one block of coefficients.
179
void j_rev_dct(DCTBLOCK data)
181
int32_t tmp0, tmp1, tmp2, tmp3;
182
int32_t tmp10, tmp11, tmp12, tmp13;
183
int32_t z1, z2, z3, z4, z5;
184
int32_t d0, d1, d2, d3, d4, d5, d6, d7;
185
register DCTELEM *dataptr;
188
/* Pass 1: process rows. */
189
/* Note results are scaled up by sqrt(8) compared to a true IDCT; */
190
/* furthermore, we scale the results by 2**PASS1_BITS. */
194
for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
195
/* Due to quantization, we will usually find that many of the input
196
* coefficients are zero, especially the AC terms. We can exploit this
197
* by short-circuiting the IDCT calculation for any row in which all
198
* the AC terms are zero. In that case each output is equal to the
199
* DC coefficient (with scale factor as needed).
200
* With typical images and quantization tables, half or more of the
201
* row DCT calculations can be simplified this way.
204
register int *idataptr = (int*)dataptr;
206
/* WARNING: we do the same permutation as MMX idct to simplify the
217
if ((d1 | d2 | d3 | d4 | d5 | d6 | d7) == 0) {
218
/* AC terms all zero */
220
/* Compute a 32 bit value to assign. */
221
DCTELEM dcval = (DCTELEM) (d0 << PASS1_BITS);
222
register int v = (dcval & 0xffff) | ((dcval << 16) & 0xffff0000);
230
dataptr += DCTSIZE; /* advance pointer to next row */
234
/* Even part: reverse the even part of the forward DCT. */
235
/* The rotator is sqrt(2)*c(-6). */
241
/* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
242
z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
243
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
244
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
246
tmp0 = (d0 + d4) << CONST_BITS;
247
tmp1 = (d0 - d4) << CONST_BITS;
254
/* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */
255
z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
256
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
257
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
259
tmp0 = d4 << CONST_BITS;
264
tmp12 = -(tmp0 + tmp2);
268
/* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
269
tmp2 = MULTIPLY(-d6, FIX_1_306562965);
270
tmp3 = MULTIPLY(d6, FIX_0_541196100);
272
tmp0 = (d0 + d4) << CONST_BITS;
273
tmp1 = (d0 - d4) << CONST_BITS;
280
/* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */
281
tmp2 = MULTIPLY(-d6, FIX_1_306562965);
282
tmp3 = MULTIPLY(d6, FIX_0_541196100);
284
tmp0 = d4 << CONST_BITS;
289
tmp12 = -(tmp0 + tmp2);
295
/* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */
296
z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
297
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
298
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
300
tmp0 = d0 << CONST_BITS;
307
/* d0 == 0, d2 != 0, d4 == 0, d6 != 0 */
308
z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
309
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
310
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
319
/* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */
320
tmp2 = MULTIPLY(-d6, FIX_1_306562965);
321
tmp3 = MULTIPLY(d6, FIX_0_541196100);
323
tmp0 = d0 << CONST_BITS;
330
/* d0 == 0, d2 == 0, d4 == 0, d6 != 0 */
331
tmp2 = MULTIPLY(-d6, FIX_1_306562965);
332
tmp3 = MULTIPLY(d6, FIX_0_541196100);
345
/* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
346
tmp2 = MULTIPLY(d2, FIX_0_541196100);
347
tmp3 = MULTIPLY(d2, FIX_1_306562965);
349
tmp0 = (d0 + d4) << CONST_BITS;
350
tmp1 = (d0 - d4) << CONST_BITS;
357
/* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */
358
tmp2 = MULTIPLY(d2, FIX_0_541196100);
359
tmp3 = MULTIPLY(d2, FIX_1_306562965);
361
tmp0 = d4 << CONST_BITS;
366
tmp12 = -(tmp0 + tmp2);
370
/* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
371
tmp10 = tmp13 = (d0 + d4) << CONST_BITS;
372
tmp11 = tmp12 = (d0 - d4) << CONST_BITS;
374
/* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */
375
tmp10 = tmp13 = d4 << CONST_BITS;
376
tmp11 = tmp12 = -tmp10;
382
/* d0 != 0, d2 != 0, d4 == 0, d6 == 0 */
383
tmp2 = MULTIPLY(d2, FIX_0_541196100);
384
tmp3 = MULTIPLY(d2, FIX_1_306562965);
386
tmp0 = d0 << CONST_BITS;
393
/* d0 == 0, d2 != 0, d4 == 0, d6 == 0 */
394
tmp2 = MULTIPLY(d2, FIX_0_541196100);
395
tmp3 = MULTIPLY(d2, FIX_1_306562965);
404
/* d0 != 0, d2 == 0, d4 == 0, d6 == 0 */
405
tmp10 = tmp13 = tmp11 = tmp12 = d0 << CONST_BITS;
407
/* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */
408
tmp10 = tmp13 = tmp11 = tmp12 = 0;
414
/* Odd part per figure 8; the matrix is unitary and hence its
415
* transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
422
/* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */
427
z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
429
tmp0 = MULTIPLY(d7, FIX_0_298631336);
430
tmp1 = MULTIPLY(d5, FIX_2_053119869);
431
tmp2 = MULTIPLY(d3, FIX_3_072711026);
432
tmp3 = MULTIPLY(d1, FIX_1_501321110);
433
z1 = MULTIPLY(-z1, FIX_0_899976223);
434
z2 = MULTIPLY(-z2, FIX_2_562915447);
435
z3 = MULTIPLY(-z3, FIX_1_961570560);
436
z4 = MULTIPLY(-z4, FIX_0_390180644);
446
/* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */
449
z5 = MULTIPLY(z3 + d5, FIX_1_175875602);
451
tmp0 = MULTIPLY(d7, FIX_0_298631336);
452
tmp1 = MULTIPLY(d5, FIX_2_053119869);
453
tmp2 = MULTIPLY(d3, FIX_3_072711026);
454
z1 = MULTIPLY(-d7, FIX_0_899976223);
455
z2 = MULTIPLY(-z2, FIX_2_562915447);
456
z3 = MULTIPLY(-z3, FIX_1_961570560);
457
z4 = MULTIPLY(-d5, FIX_0_390180644);
469
/* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */
472
z5 = MULTIPLY(d7 + z4, FIX_1_175875602);
474
tmp0 = MULTIPLY(d7, FIX_0_298631336);
475
tmp1 = MULTIPLY(d5, FIX_2_053119869);
476
tmp3 = MULTIPLY(d1, FIX_1_501321110);
477
z1 = MULTIPLY(-z1, FIX_0_899976223);
478
z2 = MULTIPLY(-d5, FIX_2_562915447);
479
z3 = MULTIPLY(-d7, FIX_1_961570560);
480
z4 = MULTIPLY(-z4, FIX_0_390180644);
490
/* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */
491
tmp0 = MULTIPLY(-d7, FIX_0_601344887);
492
z1 = MULTIPLY(-d7, FIX_0_899976223);
493
z3 = MULTIPLY(-d7, FIX_1_961570560);
494
tmp1 = MULTIPLY(-d5, FIX_0_509795579);
495
z2 = MULTIPLY(-d5, FIX_2_562915447);
496
z4 = MULTIPLY(-d5, FIX_0_390180644);
497
z5 = MULTIPLY(d5 + d7, FIX_1_175875602);
511
/* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */
514
z5 = MULTIPLY(z3 + d1, FIX_1_175875602);
516
tmp0 = MULTIPLY(d7, FIX_0_298631336);
517
tmp2 = MULTIPLY(d3, FIX_3_072711026);
518
tmp3 = MULTIPLY(d1, FIX_1_501321110);
519
z1 = MULTIPLY(-z1, FIX_0_899976223);
520
z2 = MULTIPLY(-d3, FIX_2_562915447);
521
z3 = MULTIPLY(-z3, FIX_1_961570560);
522
z4 = MULTIPLY(-d1, FIX_0_390180644);
532
/* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
535
tmp0 = MULTIPLY(-d7, FIX_0_601344887);
536
z1 = MULTIPLY(-d7, FIX_0_899976223);
537
tmp2 = MULTIPLY(d3, FIX_0_509795579);
538
z2 = MULTIPLY(-d3, FIX_2_562915447);
539
z5 = MULTIPLY(z3, FIX_1_175875602);
540
z3 = MULTIPLY(-z3, FIX_0_785694958);
549
/* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
551
z5 = MULTIPLY(z1, FIX_1_175875602);
553
z1 = MULTIPLY(z1, FIX_0_275899380);
554
z3 = MULTIPLY(-d7, FIX_1_961570560);
555
tmp0 = MULTIPLY(-d7, FIX_1_662939225);
556
z4 = MULTIPLY(-d1, FIX_0_390180644);
557
tmp3 = MULTIPLY(d1, FIX_1_111140466);
564
/* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
565
tmp0 = MULTIPLY(-d7, FIX_1_387039845);
566
tmp1 = MULTIPLY(d7, FIX_1_175875602);
567
tmp2 = MULTIPLY(-d7, FIX_0_785694958);
568
tmp3 = MULTIPLY(d7, FIX_0_275899380);
576
/* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
579
z5 = MULTIPLY(d3 + z4, FIX_1_175875602);
581
tmp1 = MULTIPLY(d5, FIX_2_053119869);
582
tmp2 = MULTIPLY(d3, FIX_3_072711026);
583
tmp3 = MULTIPLY(d1, FIX_1_501321110);
584
z1 = MULTIPLY(-d1, FIX_0_899976223);
585
z2 = MULTIPLY(-z2, FIX_2_562915447);
586
z3 = MULTIPLY(-d3, FIX_1_961570560);
587
z4 = MULTIPLY(-z4, FIX_0_390180644);
597
/* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
600
z5 = MULTIPLY(z2, FIX_1_175875602);
601
tmp1 = MULTIPLY(d5, FIX_1_662939225);
602
z4 = MULTIPLY(-d5, FIX_0_390180644);
603
z2 = MULTIPLY(-z2, FIX_1_387039845);
604
tmp2 = MULTIPLY(d3, FIX_1_111140466);
605
z3 = MULTIPLY(-d3, FIX_1_961570560);
614
/* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
617
z5 = MULTIPLY(z4, FIX_1_175875602);
618
z1 = MULTIPLY(-d1, FIX_0_899976223);
619
tmp3 = MULTIPLY(d1, FIX_0_601344887);
620
tmp1 = MULTIPLY(-d5, FIX_0_509795579);
621
z2 = MULTIPLY(-d5, FIX_2_562915447);
622
z4 = MULTIPLY(z4, FIX_0_785694958);
629
/* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
630
tmp0 = MULTIPLY(d5, FIX_1_175875602);
631
tmp1 = MULTIPLY(d5, FIX_0_275899380);
632
tmp2 = MULTIPLY(-d5, FIX_1_387039845);
633
tmp3 = MULTIPLY(d5, FIX_0_785694958);
639
/* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
641
tmp3 = MULTIPLY(d1, FIX_0_211164243);
642
tmp2 = MULTIPLY(-d3, FIX_1_451774981);
643
z1 = MULTIPLY(d1, FIX_1_061594337);
644
z2 = MULTIPLY(-d3, FIX_2_172734803);
645
z4 = MULTIPLY(z5, FIX_0_785694958);
646
z5 = MULTIPLY(z5, FIX_1_175875602);
653
/* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
654
tmp0 = MULTIPLY(-d3, FIX_0_785694958);
655
tmp1 = MULTIPLY(-d3, FIX_1_387039845);
656
tmp2 = MULTIPLY(-d3, FIX_0_275899380);
657
tmp3 = MULTIPLY(d3, FIX_1_175875602);
661
/* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
662
tmp0 = MULTIPLY(d1, FIX_0_275899380);
663
tmp1 = MULTIPLY(d1, FIX_0_785694958);
664
tmp2 = MULTIPLY(d1, FIX_1_175875602);
665
tmp3 = MULTIPLY(d1, FIX_1_387039845);
667
/* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
668
tmp0 = tmp1 = tmp2 = tmp3 = 0;
674
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
676
dataptr[0] = (DCTELEM) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
677
dataptr[7] = (DCTELEM) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
678
dataptr[1] = (DCTELEM) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
679
dataptr[6] = (DCTELEM) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
680
dataptr[2] = (DCTELEM) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
681
dataptr[5] = (DCTELEM) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
682
dataptr[3] = (DCTELEM) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
683
dataptr[4] = (DCTELEM) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
685
dataptr += DCTSIZE; /* advance pointer to next row */
688
/* Pass 2: process columns. */
689
/* Note that we must descale the results by a factor of 8 == 2**3, */
690
/* and also undo the PASS1_BITS scaling. */
693
for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
694
/* Columns of zeroes can be exploited in the same way as we did with rows.
695
* However, the row calculation has created many nonzero AC terms, so the
696
* simplification applies less often (typically 5% to 10% of the time).
697
* On machines with very fast multiplication, it's possible that the
698
* test takes more time than it's worth. In that case this section
699
* may be commented out.
702
d0 = dataptr[DCTSIZE*0];
703
d1 = dataptr[DCTSIZE*1];
704
d2 = dataptr[DCTSIZE*2];
705
d3 = dataptr[DCTSIZE*3];
706
d4 = dataptr[DCTSIZE*4];
707
d5 = dataptr[DCTSIZE*5];
708
d6 = dataptr[DCTSIZE*6];
709
d7 = dataptr[DCTSIZE*7];
711
/* Even part: reverse the even part of the forward DCT. */
712
/* The rotator is sqrt(2)*c(-6). */
717
/* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
718
z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
719
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
720
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
722
tmp0 = (d0 + d4) << CONST_BITS;
723
tmp1 = (d0 - d4) << CONST_BITS;
730
/* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */
731
z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
732
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
733
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
735
tmp0 = d4 << CONST_BITS;
740
tmp12 = -(tmp0 + tmp2);
744
/* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
745
tmp2 = MULTIPLY(-d6, FIX_1_306562965);
746
tmp3 = MULTIPLY(d6, FIX_0_541196100);
748
tmp0 = (d0 + d4) << CONST_BITS;
749
tmp1 = (d0 - d4) << CONST_BITS;
756
/* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */
757
tmp2 = MULTIPLY(-d6, FIX_1_306562965);
758
tmp3 = MULTIPLY(d6, FIX_0_541196100);
760
tmp0 = d4 << CONST_BITS;
765
tmp12 = -(tmp0 + tmp2);
771
/* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */
772
z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
773
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
774
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
776
tmp0 = d0 << CONST_BITS;
783
/* d0 == 0, d2 != 0, d4 == 0, d6 != 0 */
784
z1 = MULTIPLY(d2 + d6, FIX_0_541196100);
785
tmp2 = z1 + MULTIPLY(-d6, FIX_1_847759065);
786
tmp3 = z1 + MULTIPLY(d2, FIX_0_765366865);
795
/* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */
796
tmp2 = MULTIPLY(-d6, FIX_1_306562965);
797
tmp3 = MULTIPLY(d6, FIX_0_541196100);
799
tmp0 = d0 << CONST_BITS;
806
/* d0 == 0, d2 == 0, d4 == 0, d6 != 0 */
807
tmp2 = MULTIPLY(-d6, FIX_1_306562965);
808
tmp3 = MULTIPLY(d6, FIX_0_541196100);
821
/* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
822
tmp2 = MULTIPLY(d2, FIX_0_541196100);
823
tmp3 = MULTIPLY(d2, FIX_1_306562965);
825
tmp0 = (d0 + d4) << CONST_BITS;
826
tmp1 = (d0 - d4) << CONST_BITS;
833
/* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */
834
tmp2 = MULTIPLY(d2, FIX_0_541196100);
835
tmp3 = MULTIPLY(d2, FIX_1_306562965);
837
tmp0 = d4 << CONST_BITS;
842
tmp12 = -(tmp0 + tmp2);
846
/* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
847
tmp10 = tmp13 = (d0 + d4) << CONST_BITS;
848
tmp11 = tmp12 = (d0 - d4) << CONST_BITS;
850
/* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */
851
tmp10 = tmp13 = d4 << CONST_BITS;
852
tmp11 = tmp12 = -tmp10;
858
/* d0 != 0, d2 != 0, d4 == 0, d6 == 0 */
859
tmp2 = MULTIPLY(d2, FIX_0_541196100);
860
tmp3 = MULTIPLY(d2, FIX_1_306562965);
862
tmp0 = d0 << CONST_BITS;
869
/* d0 == 0, d2 != 0, d4 == 0, d6 == 0 */
870
tmp2 = MULTIPLY(d2, FIX_0_541196100);
871
tmp3 = MULTIPLY(d2, FIX_1_306562965);
880
/* d0 != 0, d2 == 0, d4 == 0, d6 == 0 */
881
tmp10 = tmp13 = tmp11 = tmp12 = d0 << CONST_BITS;
883
/* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */
884
tmp10 = tmp13 = tmp11 = tmp12 = 0;
890
/* Odd part per figure 8; the matrix is unitary and hence its
891
* transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
897
/* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */
902
z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
904
tmp0 = MULTIPLY(d7, FIX_0_298631336);
905
tmp1 = MULTIPLY(d5, FIX_2_053119869);
906
tmp2 = MULTIPLY(d3, FIX_3_072711026);
907
tmp3 = MULTIPLY(d1, FIX_1_501321110);
908
z1 = MULTIPLY(-z1, FIX_0_899976223);
909
z2 = MULTIPLY(-z2, FIX_2_562915447);
910
z3 = MULTIPLY(-z3, FIX_1_961570560);
911
z4 = MULTIPLY(-z4, FIX_0_390180644);
921
/* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */
925
z5 = MULTIPLY(z3 + d5, FIX_1_175875602);
927
tmp0 = MULTIPLY(d7, FIX_0_298631336);
928
tmp1 = MULTIPLY(d5, FIX_2_053119869);
929
tmp2 = MULTIPLY(d3, FIX_3_072711026);
930
z1 = MULTIPLY(-d7, FIX_0_899976223);
931
z2 = MULTIPLY(-z2, FIX_2_562915447);
932
z3 = MULTIPLY(-z3, FIX_1_961570560);
933
z4 = MULTIPLY(-d5, FIX_0_390180644);
945
/* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */
950
z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
952
tmp0 = MULTIPLY(d7, FIX_0_298631336);
953
tmp1 = MULTIPLY(d5, FIX_2_053119869);
954
tmp3 = MULTIPLY(d1, FIX_1_501321110);
955
z1 = MULTIPLY(-z1, FIX_0_899976223);
956
z2 = MULTIPLY(-d5, FIX_2_562915447);
957
z3 = MULTIPLY(-d7, FIX_1_961570560);
958
z4 = MULTIPLY(-z4, FIX_0_390180644);
968
/* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */
969
tmp0 = MULTIPLY(-d7, FIX_0_601344887);
970
z1 = MULTIPLY(-d7, FIX_0_899976223);
971
z3 = MULTIPLY(-d7, FIX_1_961570560);
972
tmp1 = MULTIPLY(-d5, FIX_0_509795579);
973
z2 = MULTIPLY(-d5, FIX_2_562915447);
974
z4 = MULTIPLY(-d5, FIX_0_390180644);
975
z5 = MULTIPLY(d5 + d7, FIX_1_175875602);
989
/* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */
992
z5 = MULTIPLY(z3 + d1, FIX_1_175875602);
994
tmp0 = MULTIPLY(d7, FIX_0_298631336);
995
tmp2 = MULTIPLY(d3, FIX_3_072711026);
996
tmp3 = MULTIPLY(d1, FIX_1_501321110);
997
z1 = MULTIPLY(-z1, FIX_0_899976223);
998
z2 = MULTIPLY(-d3, FIX_2_562915447);
999
z3 = MULTIPLY(-z3, FIX_1_961570560);
1000
z4 = MULTIPLY(-d1, FIX_0_390180644);
1010
/* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
1013
tmp0 = MULTIPLY(-d7, FIX_0_601344887);
1014
z1 = MULTIPLY(-d7, FIX_0_899976223);
1015
tmp2 = MULTIPLY(d3, FIX_0_509795579);
1016
z2 = MULTIPLY(-d3, FIX_2_562915447);
1017
z5 = MULTIPLY(z3, FIX_1_175875602);
1018
z3 = MULTIPLY(-z3, FIX_0_785694958);
1027
/* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
1029
z5 = MULTIPLY(z1, FIX_1_175875602);
1031
z1 = MULTIPLY(z1, FIX_0_275899380);
1032
z3 = MULTIPLY(-d7, FIX_1_961570560);
1033
tmp0 = MULTIPLY(-d7, FIX_1_662939225);
1034
z4 = MULTIPLY(-d1, FIX_0_390180644);
1035
tmp3 = MULTIPLY(d1, FIX_1_111140466);
1042
/* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
1043
tmp0 = MULTIPLY(-d7, FIX_1_387039845);
1044
tmp1 = MULTIPLY(d7, FIX_1_175875602);
1045
tmp2 = MULTIPLY(-d7, FIX_0_785694958);
1046
tmp3 = MULTIPLY(d7, FIX_0_275899380);
1054
/* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
1057
z5 = MULTIPLY(d3 + z4, FIX_1_175875602);
1059
tmp1 = MULTIPLY(d5, FIX_2_053119869);
1060
tmp2 = MULTIPLY(d3, FIX_3_072711026);
1061
tmp3 = MULTIPLY(d1, FIX_1_501321110);
1062
z1 = MULTIPLY(-d1, FIX_0_899976223);
1063
z2 = MULTIPLY(-z2, FIX_2_562915447);
1064
z3 = MULTIPLY(-d3, FIX_1_961570560);
1065
z4 = MULTIPLY(-z4, FIX_0_390180644);
1075
/* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
1078
z5 = MULTIPLY(z2, FIX_1_175875602);
1079
tmp1 = MULTIPLY(d5, FIX_1_662939225);
1080
z4 = MULTIPLY(-d5, FIX_0_390180644);
1081
z2 = MULTIPLY(-z2, FIX_1_387039845);
1082
tmp2 = MULTIPLY(d3, FIX_1_111140466);
1083
z3 = MULTIPLY(-d3, FIX_1_961570560);
1092
/* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
1095
z5 = MULTIPLY(z4, FIX_1_175875602);
1096
z1 = MULTIPLY(-d1, FIX_0_899976223);
1097
tmp3 = MULTIPLY(d1, FIX_0_601344887);
1098
tmp1 = MULTIPLY(-d5, FIX_0_509795579);
1099
z2 = MULTIPLY(-d5, FIX_2_562915447);
1100
z4 = MULTIPLY(z4, FIX_0_785694958);
1107
/* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
1108
tmp0 = MULTIPLY(d5, FIX_1_175875602);
1109
tmp1 = MULTIPLY(d5, FIX_0_275899380);
1110
tmp2 = MULTIPLY(-d5, FIX_1_387039845);
1111
tmp3 = MULTIPLY(d5, FIX_0_785694958);
1117
/* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
1119
tmp3 = MULTIPLY(d1, FIX_0_211164243);
1120
tmp2 = MULTIPLY(-d3, FIX_1_451774981);
1121
z1 = MULTIPLY(d1, FIX_1_061594337);
1122
z2 = MULTIPLY(-d3, FIX_2_172734803);
1123
z4 = MULTIPLY(z5, FIX_0_785694958);
1124
z5 = MULTIPLY(z5, FIX_1_175875602);
1131
/* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
1132
tmp0 = MULTIPLY(-d3, FIX_0_785694958);
1133
tmp1 = MULTIPLY(-d3, FIX_1_387039845);
1134
tmp2 = MULTIPLY(-d3, FIX_0_275899380);
1135
tmp3 = MULTIPLY(d3, FIX_1_175875602);
1139
/* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
1140
tmp0 = MULTIPLY(d1, FIX_0_275899380);
1141
tmp1 = MULTIPLY(d1, FIX_0_785694958);
1142
tmp2 = MULTIPLY(d1, FIX_1_175875602);
1143
tmp3 = MULTIPLY(d1, FIX_1_387039845);
1145
/* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
1146
tmp0 = tmp1 = tmp2 = tmp3 = 0;
1152
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
1154
dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp3,
1155
CONST_BITS+PASS1_BITS+3);
1156
dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(tmp10 - tmp3,
1157
CONST_BITS+PASS1_BITS+3);
1158
dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp11 + tmp2,
1159
CONST_BITS+PASS1_BITS+3);
1160
dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(tmp11 - tmp2,
1161
CONST_BITS+PASS1_BITS+3);
1162
dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(tmp12 + tmp1,
1163
CONST_BITS+PASS1_BITS+3);
1164
dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp12 - tmp1,
1165
CONST_BITS+PASS1_BITS+3);
1166
dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(tmp13 + tmp0,
1167
CONST_BITS+PASS1_BITS+3);
1168
dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp13 - tmp0,
1169
CONST_BITS+PASS1_BITS+3);
1171
dataptr++; /* advance pointer to next column */
added
removed
extras/ffmpeg/libavcodec/jrevdct.c
