FFmpeg coverage

GCC Code Coverage Report

Directory:	../../../ffmpeg/		Exec	Total	Coverage
File:	src/libavcodec/jfdctfst.c	Lines:	71	102	69.6 %
Date:	2021-03-07 19:55:24	Branches:	4	6	66.7 %


/*
 * This file is part of the Independent JPEG Group's software.
 *
 * The authors make NO WARRANTY or representation, either express or implied,
 * with respect to this software, its quality, accuracy, merchantability, or
 * fitness for a particular purpose.  This software is provided "AS IS", and
 * you, its user, assume the entire risk as to its quality and accuracy.
 *
 * This software is copyright (C) 1994-1996, Thomas G. Lane.
 * All Rights Reserved except as specified below.
 *
 * Permission is hereby granted to use, copy, modify, and distribute this
 * software (or portions thereof) for any purpose, without fee, subject to
 * these conditions:
 * (1) If any part of the source code for this software is distributed, then
 * this README file must be included, with this copyright and no-warranty
 * notice unaltered; and any additions, deletions, or changes to the original
 * files must be clearly indicated in accompanying documentation.
 * (2) If only executable code is distributed, then the accompanying
 * documentation must state that "this software is based in part on the work
 * of the Independent JPEG Group".
 * (3) Permission for use of this software is granted only if the user accepts
 * full responsibility for any undesirable consequences; the authors accept
 * NO LIABILITY for damages of any kind.
 *
 * These conditions apply to any software derived from or based on the IJG
 * code, not just to the unmodified library.  If you use our work, you ought
 * to acknowledge us.
 *
 * Permission is NOT granted for the use of any IJG author's name or company
 * name in advertising or publicity relating to this software or products
 * derived from it.  This software may be referred to only as "the Independent
 * JPEG Group's software".
 *
 * We specifically permit and encourage the use of this software as the basis
 * of commercial products, provided that all warranty or liability claims are
 * assumed by the product vendor.
 *
 * This file contains a fast, not so accurate integer implementation of the
 * forward DCT (Discrete Cosine Transform).
 *
 * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
 * on each column.  Direct algorithms are also available, but they are
 * much more complex and seem not to be any faster when reduced to code.
 *
 * This implementation is based on Arai, Agui, and Nakajima's algorithm for
 * scaled DCT.  Their original paper (Trans. IEICE E-71(11):1095) is in
 * Japanese, but the algorithm is described in the Pennebaker & Mitchell
 * JPEG textbook (see REFERENCES section in file README).  The following code
 * is based directly on figure 4-8 in P&M.
 * While an 8-point DCT cannot be done in less than 11 multiplies, it is
 * possible to arrange the computation so that many of the multiplies are
 * simple scalings of the final outputs.  These multiplies can then be
 * folded into the multiplications or divisions by the JPEG quantization
 * table entries.  The AA&N method leaves only 5 multiplies and 29 adds
 * to be done in the DCT itself.
 * The primary disadvantage of this method is that with fixed-point math,
 * accuracy is lost due to imprecise representation of the scaled
 * quantization values.  The smaller the quantization table entry, the less
 * precise the scaled value, so this implementation does worse with high-
 * quality-setting files than with low-quality ones.
 */

/**
 * @file
 * Independent JPEG Group's fast AAN dct.
 */

#include <stdlib.h>
#include <stdio.h>
#include "libavutil/common.h"
#include "dct.h"

#define DCTSIZE 8
#define GLOBAL(x) x
#define RIGHT_SHIFT(x, n) ((x) >> (n))

/*
 * This module is specialized to the case DCTSIZE = 8.
 */

#if DCTSIZE != 8
  Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
#endif


/* Scaling decisions are generally the same as in the LL&M algorithm;
 * see jfdctint.c for more details.  However, we choose to descale
 * (right shift) multiplication products as soon as they are formed,
 * rather than carrying additional fractional bits into subsequent additions.
 * This compromises accuracy slightly, but it lets us save a few shifts.
 * More importantly, 16-bit arithmetic is then adequate (for 8-bit samples)
 * everywhere except in the multiplications proper; this saves a good deal
 * of work on 16-bit-int machines.
 *
 * Again to save a few shifts, the intermediate results between pass 1 and
 * pass 2 are not upscaled, but are represented only to integral precision.
 *
 * A final compromise is to represent the multiplicative constants to only
 * 8 fractional bits, rather than 13.  This saves some shifting work on some
 * machines, and may also reduce the cost of multiplication (since there
 * are fewer one-bits in the constants).
 */

#define CONST_BITS  8


/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
 * causing a lot of useless floating-point operations at run time.
 * To get around this we use the following pre-calculated constants.
 * If you change CONST_BITS you may want to add appropriate values.
 * (With a reasonable C compiler, you can just rely on the FIX() macro...)
 */

#if CONST_BITS == 8
#define FIX_0_382683433  ((int32_t)   98)       /* FIX(0.382683433) */
#define FIX_0_541196100  ((int32_t)  139)       /* FIX(0.541196100) */
#define FIX_0_707106781  ((int32_t)  181)       /* FIX(0.707106781) */
#define FIX_1_306562965  ((int32_t)  334)       /* FIX(1.306562965) */
#else
#define FIX_0_382683433  FIX(0.382683433)
#define FIX_0_541196100  FIX(0.541196100)
#define FIX_0_707106781  FIX(0.707106781)
#define FIX_1_306562965  FIX(1.306562965)
#endif


/* We can gain a little more speed, with a further compromise in accuracy,
 * by omitting the addition in a descaling shift.  This yields an incorrectly
 * rounded result half the time...
 */

#ifndef USE_ACCURATE_ROUNDING
#undef DESCALE
#define DESCALE(x,n)  RIGHT_SHIFT(x, n)
#endif


/* Multiply a int16_t variable by an int32_t constant, and immediately
 * descale to yield a int16_t result.
 */

#define MULTIPLY(var,const)  ((int16_t) DESCALE((var) * (const), CONST_BITS))

static av_always_inline void row_fdct(int16_t * data){
  int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
  int tmp10, tmp11, tmp12, tmp13;
  int z1, z2, z3, z4, z5, z11, z13;
  int16_t *dataptr;
  int ctr;

  /* Pass 1: process rows. */

  dataptr = data;
  for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
    tmp0 = dataptr[0] + dataptr[7];
    tmp7 = dataptr[0] - dataptr[7];
    tmp1 = dataptr[1] + dataptr[6];
    tmp6 = dataptr[1] - dataptr[6];
    tmp2 = dataptr[2] + dataptr[5];
    tmp5 = dataptr[2] - dataptr[5];
    tmp3 = dataptr[3] + dataptr[4];
    tmp4 = dataptr[3] - dataptr[4];

    /* Even part */

    tmp10 = tmp0 + tmp3;        /* phase 2 */
    tmp13 = tmp0 - tmp3;
    tmp11 = tmp1 + tmp2;
    tmp12 = tmp1 - tmp2;

    dataptr[0] = tmp10 + tmp11; /* phase 3 */
    dataptr[4] = tmp10 - tmp11;

    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
    dataptr[2] = tmp13 + z1;    /* phase 5 */
    dataptr[6] = tmp13 - z1;

    /* Odd part */

    tmp10 = tmp4 + tmp5;        /* phase 2 */
    tmp11 = tmp5 + tmp6;
    tmp12 = tmp6 + tmp7;

    /* The rotator is modified from fig 4-8 to avoid extra negations. */
    z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
    z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5;    /* c2-c6 */
    z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5;    /* c2+c6 */
    z3 = MULTIPLY(tmp11, FIX_0_707106781);         /* c4 */

    z11 = tmp7 + z3;            /* phase 5 */
    z13 = tmp7 - z3;

    dataptr[5] = z13 + z2;      /* phase 6 */
    dataptr[3] = z13 - z2;
    dataptr[1] = z11 + z4;
    dataptr[7] = z11 - z4;

    dataptr += DCTSIZE;         /* advance pointer to next row */
  }
}

/*
 * Perform the forward DCT on one block of samples.
 */

GLOBAL(void)
ff_fdct_ifast (int16_t * data)
{
  int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
  int tmp10, tmp11, tmp12, tmp13;
  int z1, z2, z3, z4, z5, z11, z13;
  int16_t *dataptr;
  int ctr;

  row_fdct(data);

  /* Pass 2: process columns. */

  dataptr = data;
  for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
    tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
    tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
    tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
    tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
    tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
    tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
    tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
    tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];

    /* Even part */

    tmp10 = tmp0 + tmp3;        /* phase 2 */
    tmp13 = tmp0 - tmp3;
    tmp11 = tmp1 + tmp2;
    tmp12 = tmp1 - tmp2;

    dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */
    dataptr[DCTSIZE*4] = tmp10 - tmp11;

    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
    dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */
    dataptr[DCTSIZE*6] = tmp13 - z1;

    /* Odd part */

    tmp10 = tmp4 + tmp5;        /* phase 2 */
    tmp11 = tmp5 + tmp6;
    tmp12 = tmp6 + tmp7;

    /* The rotator is modified from fig 4-8 to avoid extra negations. */
    z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
    z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
    z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
    z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */

    z11 = tmp7 + z3;            /* phase 5 */
    z13 = tmp7 - z3;

    dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */
    dataptr[DCTSIZE*3] = z13 - z2;
    dataptr[DCTSIZE*1] = z11 + z4;
    dataptr[DCTSIZE*7] = z11 - z4;

    dataptr++;                  /* advance pointer to next column */
  }
}

/*
 * Perform the forward 2-4-8 DCT on one block of samples.
 */

GLOBAL(void)
ff_fdct_ifast248 (int16_t * data)
{
  int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
  int tmp10, tmp11, tmp12, tmp13;
  int z1;
  int16_t *dataptr;
  int ctr;

  row_fdct(data);

  /* Pass 2: process columns. */

  dataptr = data;
  for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
    tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*1];
    tmp1 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*3];
    tmp2 = dataptr[DCTSIZE*4] + dataptr[DCTSIZE*5];
    tmp3 = dataptr[DCTSIZE*6] + dataptr[DCTSIZE*7];
    tmp4 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*1];
    tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*3];
    tmp6 = dataptr[DCTSIZE*4] - dataptr[DCTSIZE*5];
    tmp7 = dataptr[DCTSIZE*6] - dataptr[DCTSIZE*7];

    /* Even part */

    tmp10 = tmp0 + tmp3;
    tmp11 = tmp1 + tmp2;
    tmp12 = tmp1 - tmp2;
    tmp13 = tmp0 - tmp3;

    dataptr[DCTSIZE*0] = tmp10 + tmp11;
    dataptr[DCTSIZE*4] = tmp10 - tmp11;

    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781);
    dataptr[DCTSIZE*2] = tmp13 + z1;
    dataptr[DCTSIZE*6] = tmp13 - z1;

    tmp10 = tmp4 + tmp7;
    tmp11 = tmp5 + tmp6;
    tmp12 = tmp5 - tmp6;
    tmp13 = tmp4 - tmp7;

    dataptr[DCTSIZE*1] = tmp10 + tmp11;
    dataptr[DCTSIZE*5] = tmp10 - tmp11;

    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781);
    dataptr[DCTSIZE*3] = tmp13 + z1;
    dataptr[DCTSIZE*7] = tmp13 - z1;

    dataptr++;                        /* advance pointer to next column */
  }
}


#undef GLOBAL
#undef CONST_BITS
#undef DESCALE
#undef FIX_0_541196100
#undef FIX_1_306562965


Generated by: GCOVR (Version 4.2)

Line	Branch	Exec	Source
1			/*
2			* This file is part of the Independent JPEG Group's software.
3			*
4			* The authors make NO WARRANTY or representation, either express or implied,
5			* with respect to this software, its quality, accuracy, merchantability, or
6			* fitness for a particular purpose. This software is provided "AS IS", and
7			* you, its user, assume the entire risk as to its quality and accuracy.
8			*
9			* This software is copyright (C) 1994-1996, Thomas G. Lane.
10			* All Rights Reserved except as specified below.
11			*
12			* Permission is hereby granted to use, copy, modify, and distribute this
13			* software (or portions thereof) for any purpose, without fee, subject to
14			* these conditions:
15			* (1) If any part of the source code for this software is distributed, then
16			* this README file must be included, with this copyright and no-warranty
17			* notice unaltered; and any additions, deletions, or changes to the original
18			* files must be clearly indicated in accompanying documentation.
19			* (2) If only executable code is distributed, then the accompanying
20			* documentation must state that "this software is based in part on the work
21			* of the Independent JPEG Group".
22			* (3) Permission for use of this software is granted only if the user accepts
23			* full responsibility for any undesirable consequences; the authors accept
24			* NO LIABILITY for damages of any kind.
25			*
26			* These conditions apply to any software derived from or based on the IJG
27			* code, not just to the unmodified library. If you use our work, you ought
28			* to acknowledge us.
29			*
30			* Permission is NOT granted for the use of any IJG author's name or company
31			* name in advertising or publicity relating to this software or products
32			* derived from it. This software may be referred to only as "the Independent
33			* JPEG Group's software".
34			*
35			* We specifically permit and encourage the use of this software as the basis
36			* of commercial products, provided that all warranty or liability claims are
37			* assumed by the product vendor.
38			*
39			* This file contains a fast, not so accurate integer implementation of the
40			* forward DCT (Discrete Cosine Transform).
41			*
42			* A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
43			* on each column. Direct algorithms are also available, but they are
44			* much more complex and seem not to be any faster when reduced to code.
45			*
46			* This implementation is based on Arai, Agui, and Nakajima's algorithm for
47			* scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
48			* Japanese, but the algorithm is described in the Pennebaker & Mitchell
49			* JPEG textbook (see REFERENCES section in file README). The following code
50			* is based directly on figure 4-8 in P&M.
51			* While an 8-point DCT cannot be done in less than 11 multiplies, it is
52			* possible to arrange the computation so that many of the multiplies are
53			* simple scalings of the final outputs. These multiplies can then be
54			* folded into the multiplications or divisions by the JPEG quantization
55			* table entries. The AA&N method leaves only 5 multiplies and 29 adds
56			* to be done in the DCT itself.
57			* The primary disadvantage of this method is that with fixed-point math,
58			* accuracy is lost due to imprecise representation of the scaled
59			* quantization values. The smaller the quantization table entry, the less
60			* precise the scaled value, so this implementation does worse with high-
61			* quality-setting files than with low-quality ones.
62			*/
63
64			/**
65			* @file
66			* Independent JPEG Group's fast AAN dct.
67			*/
68
69			#include <stdlib.h>
70			#include <stdio.h>
71			#include "libavutil/common.h"
72			#include "dct.h"
73
74			#define DCTSIZE 8
75			#define GLOBAL(x) x
76			#define RIGHT_SHIFT(x, n) ((x) >> (n))
77
78			/*
79			* This module is specialized to the case DCTSIZE = 8.
80			*/
81
82			#if DCTSIZE != 8
83			Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
84			#endif
85
86
87			/* Scaling decisions are generally the same as in the LL&M algorithm;
88			* see jfdctint.c for more details. However, we choose to descale
89			* (right shift) multiplication products as soon as they are formed,
90			* rather than carrying additional fractional bits into subsequent additions.
91			* This compromises accuracy slightly, but it lets us save a few shifts.
92			* More importantly, 16-bit arithmetic is then adequate (for 8-bit samples)
93			* everywhere except in the multiplications proper; this saves a good deal
94			* of work on 16-bit-int machines.
95			*
96			* Again to save a few shifts, the intermediate results between pass 1 and
97			* pass 2 are not upscaled, but are represented only to integral precision.
98			*
99			* A final compromise is to represent the multiplicative constants to only
100			* 8 fractional bits, rather than 13. This saves some shifting work on some
101			* machines, and may also reduce the cost of multiplication (since there
102			* are fewer one-bits in the constants).
103			*/
104
105			#define CONST_BITS 8
106
107
108			/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
109			* causing a lot of useless floating-point operations at run time.
110			* To get around this we use the following pre-calculated constants.
111			* If you change CONST_BITS you may want to add appropriate values.
112			* (With a reasonable C compiler, you can just rely on the FIX() macro...)
113			*/
114
115			#if CONST_BITS == 8
116			#define FIX_0_382683433 ((int32_t) 98) /* FIX(0.382683433) */
117			#define FIX_0_541196100 ((int32_t) 139) /* FIX(0.541196100) */
118			#define FIX_0_707106781 ((int32_t) 181) /* FIX(0.707106781) */
119			#define FIX_1_306562965 ((int32_t) 334) /* FIX(1.306562965) */
120			#else
121			#define FIX_0_382683433 FIX(0.382683433)
122			#define FIX_0_541196100 FIX(0.541196100)
123			#define FIX_0_707106781 FIX(0.707106781)
124			#define FIX_1_306562965 FIX(1.306562965)
125			#endif
126
127
128			/* We can gain a little more speed, with a further compromise in accuracy,
129			* by omitting the addition in a descaling shift. This yields an incorrectly
130			* rounded result half the time...
131			*/
132
133			#ifndef USE_ACCURATE_ROUNDING
134			#undef DESCALE
135			#define DESCALE(x,n) RIGHT_SHIFT(x, n)
136			#endif
137
138
139			/* Multiply a int16_t variable by an int32_t constant, and immediately
140			* descale to yield a int16_t result.
141			*/
142
143			#define MULTIPLY(var,const) ((int16_t) DESCALE((var) * (const), CONST_BITS))
144
145		99811350	static av_always_inline void row_fdct(int16_t * data){
146			int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
147			int tmp10, tmp11, tmp12, tmp13;
148			int z1, z2, z3, z4, z5, z11, z13;
149			int16_t *dataptr;
150			int ctr;
151
152			/* Pass 1: process rows. */
153
154		99811350	dataptr = data;
155	✓✓	898302150	for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
156		798490800	tmp0 = dataptr[0] + dataptr[7];
157		798490800	tmp7 = dataptr[0] - dataptr[7];
158		798490800	tmp1 = dataptr[1] + dataptr[6];
159		798490800	tmp6 = dataptr[1] - dataptr[6];
160		798490800	tmp2 = dataptr[2] + dataptr[5];
161		798490800	tmp5 = dataptr[2] - dataptr[5];
162		798490800	tmp3 = dataptr[3] + dataptr[4];
163		798490800	tmp4 = dataptr[3] - dataptr[4];
164
165			/* Even part */
166
167		798490800	tmp10 = tmp0 + tmp3; /* phase 2 */
168		798490800	tmp13 = tmp0 - tmp3;
169		798490800	tmp11 = tmp1 + tmp2;
170		798490800	tmp12 = tmp1 - tmp2;
171
172		798490800	dataptr[0] = tmp10 + tmp11; /* phase 3 */
173		798490800	dataptr[4] = tmp10 - tmp11;
174
175		798490800	z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
176		798490800	dataptr[2] = tmp13 + z1; /* phase 5 */
177		798490800	dataptr[6] = tmp13 - z1;
178
179			/* Odd part */
180
181		798490800	tmp10 = tmp4 + tmp5; /* phase 2 */
182		798490800	tmp11 = tmp5 + tmp6;
183		798490800	tmp12 = tmp6 + tmp7;
184
185			/* The rotator is modified from fig 4-8 to avoid extra negations. */
186		798490800	z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
187		798490800	z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
188		798490800	z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
189		798490800	z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
190
191		798490800	z11 = tmp7 + z3; /* phase 5 */
192		798490800	z13 = tmp7 - z3;
193
194		798490800	dataptr[5] = z13 + z2; /* phase 6 */
195		798490800	dataptr[3] = z13 - z2;
196		798490800	dataptr[1] = z11 + z4;
197		798490800	dataptr[7] = z11 - z4;
198
199		798490800	dataptr += DCTSIZE; /* advance pointer to next row */
200			}
201		99811350	}
202
203			/*
204			* Perform the forward DCT on one block of samples.
205			*/
206
207			GLOBAL(void)
208		99811350	ff_fdct_ifast (int16_t * data)
209			{
210			int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
211			int tmp10, tmp11, tmp12, tmp13;
212			int z1, z2, z3, z4, z5, z11, z13;
213			int16_t *dataptr;
214			int ctr;
215
216		99811350	row_fdct(data);
217
218			/* Pass 2: process columns. */
219
220		99811350	dataptr = data;
221	✓✓	898302150	for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
222		798490800	tmp0 = dataptr[DCTSIZE0] + dataptr[DCTSIZE7];
223		798490800	tmp7 = dataptr[DCTSIZE0] - dataptr[DCTSIZE7];
224		798490800	tmp1 = dataptr[DCTSIZE1] + dataptr[DCTSIZE6];
225		798490800	tmp6 = dataptr[DCTSIZE1] - dataptr[DCTSIZE6];
226		798490800	tmp2 = dataptr[DCTSIZE2] + dataptr[DCTSIZE5];
227		798490800	tmp5 = dataptr[DCTSIZE2] - dataptr[DCTSIZE5];
228		798490800	tmp3 = dataptr[DCTSIZE3] + dataptr[DCTSIZE4];
229		798490800	tmp4 = dataptr[DCTSIZE3] - dataptr[DCTSIZE4];
230
231			/* Even part */
232
233		798490800	tmp10 = tmp0 + tmp3; /* phase 2 */
234		798490800	tmp13 = tmp0 - tmp3;
235		798490800	tmp11 = tmp1 + tmp2;
236		798490800	tmp12 = tmp1 - tmp2;
237
238		798490800	dataptr[DCTSIZE0] = tmp10 + tmp11; / phase 3 */
239		798490800	dataptr[DCTSIZE*4] = tmp10 - tmp11;
240
241		798490800	z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
242		798490800	dataptr[DCTSIZE2] = tmp13 + z1; / phase 5 */
243		798490800	dataptr[DCTSIZE*6] = tmp13 - z1;
244
245			/* Odd part */
246
247		798490800	tmp10 = tmp4 + tmp5; /* phase 2 */
248		798490800	tmp11 = tmp5 + tmp6;
249		798490800	tmp12 = tmp6 + tmp7;
250
251			/* The rotator is modified from fig 4-8 to avoid extra negations. */
252		798490800	z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
253		798490800	z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
254		798490800	z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
255		798490800	z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
256
257		798490800	z11 = tmp7 + z3; /* phase 5 */
258		798490800	z13 = tmp7 - z3;
259
260		798490800	dataptr[DCTSIZE5] = z13 + z2; / phase 6 */
261		798490800	dataptr[DCTSIZE*3] = z13 - z2;
262		798490800	dataptr[DCTSIZE*1] = z11 + z4;
263		798490800	dataptr[DCTSIZE*7] = z11 - z4;
264
265		798490800	dataptr++; /* advance pointer to next column */
266			}
267		99811350	}
268
269			/*
270			* Perform the forward 2-4-8 DCT on one block of samples.
271			*/
272
273			GLOBAL(void)
274			ff_fdct_ifast248 (int16_t * data)
275			{
276			int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
277			int tmp10, tmp11, tmp12, tmp13;
278			int z1;
279			int16_t *dataptr;
280			int ctr;
281
282			row_fdct(data);
283
284			/* Pass 2: process columns. */
285
286			dataptr = data;
287			for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
288			tmp0 = dataptr[DCTSIZE0] + dataptr[DCTSIZE1];
289			tmp1 = dataptr[DCTSIZE2] + dataptr[DCTSIZE3];
290			tmp2 = dataptr[DCTSIZE4] + dataptr[DCTSIZE5];
291			tmp3 = dataptr[DCTSIZE6] + dataptr[DCTSIZE7];
292			tmp4 = dataptr[DCTSIZE0] - dataptr[DCTSIZE1];
293			tmp5 = dataptr[DCTSIZE2] - dataptr[DCTSIZE3];
294			tmp6 = dataptr[DCTSIZE4] - dataptr[DCTSIZE5];
295			tmp7 = dataptr[DCTSIZE6] - dataptr[DCTSIZE7];
296
297			/* Even part */
298
299			tmp10 = tmp0 + tmp3;
300			tmp11 = tmp1 + tmp2;
301			tmp12 = tmp1 - tmp2;
302			tmp13 = tmp0 - tmp3;
303
304			dataptr[DCTSIZE*0] = tmp10 + tmp11;
305			dataptr[DCTSIZE*4] = tmp10 - tmp11;
306
307			z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781);
308			dataptr[DCTSIZE*2] = tmp13 + z1;
309			dataptr[DCTSIZE*6] = tmp13 - z1;
310
311			tmp10 = tmp4 + tmp7;
312			tmp11 = tmp5 + tmp6;
313			tmp12 = tmp5 - tmp6;
314			tmp13 = tmp4 - tmp7;
315
316			dataptr[DCTSIZE*1] = tmp10 + tmp11;
317			dataptr[DCTSIZE*5] = tmp10 - tmp11;
318
319			z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781);
320			dataptr[DCTSIZE*3] = tmp13 + z1;
321			dataptr[DCTSIZE*7] = tmp13 - z1;
322
323			dataptr++; /* advance pointer to next column */
324			}
325			}
326
327
328			#undef GLOBAL
329			#undef CONST_BITS
330			#undef DESCALE
331			#undef FIX_0_541196100
332			#undef FIX_1_306562965