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rockbox/apps/plugins/mpegplayer/idct.c
Michael Sevakis f4b5a723b0 mpeg2dec in mpegplayer: Do a little code slashing and organizing. Much more to come I think. 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@13159 a1c6a512-1295-4272-9138-f99709370657
2007-04-14 16:35:44 +00:00

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/*
* idct.c
* Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
*
* This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
* See http://libmpeg2.sourceforge.net/ for updates.
*
* mpeg2dec is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpeg2dec is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "plugin.h"
#include "mpeg2dec_config.h"
#include "mpeg2.h"
#include "attributes.h"
#include "mpeg2_internal.h"
#define W1 2841 /* 2048 * sqrt (2) * cos (1 * pi / 16) */
#define W2 2676 /* 2048 * sqrt (2) * cos (2 * pi / 16) */
#define W3 2408 /* 2048 * sqrt (2) * cos (3 * pi / 16) */
#define W5 1609 /* 2048 * sqrt (2) * cos (5 * pi / 16) */
#define W6 1108 /* 2048 * sqrt (2) * cos (6 * pi / 16) */
#define W7 565 /* 2048 * sqrt (2) * cos (7 * pi / 16) */
/* idct main entry point */
void (* mpeg2_idct_copy) (int16_t * block, uint8_t * dest, int stride);
void (* mpeg2_idct_add) (int last, int16_t * block,
uint8_t * dest, int stride);
/*
* In legal streams, the IDCT output should be between -384 and +384.
* In corrupted streams, it is possible to force the IDCT output to go
* to +-3826 - this is the worst case for a column IDCT where the
* column inputs are 16-bit values.
*/
#ifdef CPU_COLDFIRE
static inline unsigned CLIP(int value)
{
asm ( /* Note: Uses knowledge that only the low byte of the result is used */
"cmp.l #255,%[v] \n" /* overflow? */
"bls.b 1f \n" /* no: return value */
"spl.b %[v] \n" /* yes: set low byte to appropriate boundary */
"1: \n"
: /* outputs */
[v]"+d"(value)
);
return value;
}
#elif defined CPU_ARM
static inline unsigned CLIP(int value)
{
asm volatile ( /* Note: Uses knowledge that only the low byte of the result is used */
"cmp %[v], #255 \n"
"mvnhi %[v], %[v], asr #31 \n"
: /* outputs */
[v]"+r"(value)
);
return value;
}
#else
uint8_t mpeg2_clip[3840 * 2 + 256] IBSS_ATTR;
#define CLIP(i) ((mpeg2_clip + 3840)[i])
#endif
#if 0
#define BUTTERFLY(t0,t1,W0,W1,d0,d1) \
do { \
t0 = W0 * d0 + W1 * d1; \
t1 = W0 * d1 - W1 * d0; \
} while (0)
#else
#define BUTTERFLY(t0,t1,W0,W1,d0,d1) \
do { \
int tmp = W0 * (d0 + d1); \
t0 = tmp + (W1 - W0) * d1; \
t1 = tmp - (W1 + W0) * d0; \
} while (0)
#endif
static inline void idct_row (int16_t * const block)
{
int d0, d1, d2, d3;
int a0, a1, a2, a3, b0, b1, b2, b3;
int t0, t1, t2, t3;
/* shortcut */
if (likely (!(block[1] | ((int32_t *)block)[1] | ((int32_t *)block)[2] |
((int32_t *)block)[3]))) {
uint32_t tmp = (uint16_t) (block[0] >> 1);
tmp |= tmp << 16;
((int32_t *)block)[0] = tmp;
((int32_t *)block)[1] = tmp;
((int32_t *)block)[2] = tmp;
((int32_t *)block)[3] = tmp;
return;
}
d0 = (block[0] << 11) + 2048;
d1 = block[1];
d2 = block[2] << 11;
d3 = block[3];
t0 = d0 + d2;
t1 = d0 - d2;
BUTTERFLY (t2, t3, W6, W2, d3, d1);
a0 = t0 + t2;
a1 = t1 + t3;
a2 = t1 - t3;
a3 = t0 - t2;
d0 = block[4];
d1 = block[5];
d2 = block[6];
d3 = block[7];
BUTTERFLY (t0, t1, W7, W1, d3, d0);
BUTTERFLY (t2, t3, W3, W5, d1, d2);
b0 = t0 + t2;
b3 = t1 + t3;
t0 -= t2;
t1 -= t3;
b1 = ((t0 + t1) >> 8) * 181;
b2 = ((t0 - t1) >> 8) * 181;
block[0] = (a0 + b0) >> 12;
block[1] = (a1 + b1) >> 12;
block[2] = (a2 + b2) >> 12;
block[3] = (a3 + b3) >> 12;
block[4] = (a3 - b3) >> 12;
block[5] = (a2 - b2) >> 12;
block[6] = (a1 - b1) >> 12;
block[7] = (a0 - b0) >> 12;
}
static inline void idct_col (int16_t * const block)
{
int d0, d1, d2, d3;
int a0, a1, a2, a3, b0, b1, b2, b3;
int t0, t1, t2, t3;
d0 = (block[8*0] << 11) + 65536;
d1 = block[8*1];
d2 = block[8*2] << 11;
d3 = block[8*3];
t0 = d0 + d2;
t1 = d0 - d2;
BUTTERFLY (t2, t3, W6, W2, d3, d1);
a0 = t0 + t2;
a1 = t1 + t3;
a2 = t1 - t3;
a3 = t0 - t2;
d0 = block[8*4];
d1 = block[8*5];
d2 = block[8*6];
d3 = block[8*7];
BUTTERFLY (t0, t1, W7, W1, d3, d0);
BUTTERFLY (t2, t3, W3, W5, d1, d2);
b0 = t0 + t2;
b3 = t1 + t3;
t0 -= t2;
t1 -= t3;
b1 = ((t0 + t1) >> 8) * 181;
b2 = ((t0 - t1) >> 8) * 181;
block[8*0] = (a0 + b0) >> 17;
block[8*1] = (a1 + b1) >> 17;
block[8*2] = (a2 + b2) >> 17;
block[8*3] = (a3 + b3) >> 17;
block[8*4] = (a3 - b3) >> 17;
block[8*5] = (a2 - b2) >> 17;
block[8*6] = (a1 - b1) >> 17;
block[8*7] = (a0 - b0) >> 17;
}
static void mpeg2_idct_copy_c (int16_t * block, uint8_t * dest,
const int stride)
{
int i;
for (i = 0; i < 8; i++)
idct_row (block + 8 * i);
for (i = 0; i < 8; i++)
idct_col (block + i);
do {
dest[0] = CLIP (block[0]);
dest[1] = CLIP (block[1]);
dest[2] = CLIP (block[2]);
dest[3] = CLIP (block[3]);
dest[4] = CLIP (block[4]);
dest[5] = CLIP (block[5]);
dest[6] = CLIP (block[6]);
dest[7] = CLIP (block[7]);
((int32_t *)block)[0] = 0; ((int32_t *)block)[1] = 0;
((int32_t *)block)[2] = 0; ((int32_t *)block)[3] = 0;
dest += stride;
block += 8;
} while (--i);
}
static void mpeg2_idct_add_c (const int last, int16_t * block,
uint8_t * dest, const int stride)
{
int i;
if (last != 129 || (block[0] & (7 << 4)) == (4 << 4)) {
for (i = 0; i < 8; i++)
idct_row (block + 8 * i);
for (i = 0; i < 8; i++)
idct_col (block + i);
do {
dest[0] = CLIP (block[0] + dest[0]);
dest[1] = CLIP (block[1] + dest[1]);
dest[2] = CLIP (block[2] + dest[2]);
dest[3] = CLIP (block[3] + dest[3]);
dest[4] = CLIP (block[4] + dest[4]);
dest[5] = CLIP (block[5] + dest[5]);
dest[6] = CLIP (block[6] + dest[6]);
dest[7] = CLIP (block[7] + dest[7]);
((int32_t *)block)[0] = 0; ((int32_t *)block)[1] = 0;
((int32_t *)block)[2] = 0; ((int32_t *)block)[3] = 0;
dest += stride;
block += 8;
} while (--i);
} else {
int DC;
DC = (block[0] + 64) >> 7;
block[0] = block[63] = 0;
i = 8;
do {
dest[0] = CLIP (DC + dest[0]);
dest[1] = CLIP (DC + dest[1]);
dest[2] = CLIP (DC + dest[2]);
dest[3] = CLIP (DC + dest[3]);
dest[4] = CLIP (DC + dest[4]);
dest[5] = CLIP (DC + dest[5]);
dest[6] = CLIP (DC + dest[6]);
dest[7] = CLIP (DC + dest[7]);
dest += stride;
} while (--i);
}
}
void mpeg2_idct_init (void)
{
extern uint8_t mpeg2_scan_norm[64];
extern uint8_t mpeg2_scan_alt[64];
int i, j;
mpeg2_idct_copy = mpeg2_idct_copy_c;
mpeg2_idct_add = mpeg2_idct_add_c;
#if !defined(CPU_COLDFIRE) && !defined(CPU_ARM)
for (i = -3840; i < 3840 + 256; i++)
CLIP(i) = (i < 0) ? 0 : ((i > 255) ? 255 : i);
#endif
for (i = 0; i < 64; i++)
{
j = mpeg2_scan_norm[i];
mpeg2_scan_norm[i] = ((j & 0x36) >> 1) | ((j & 0x09) << 2);
j = mpeg2_scan_alt[i];
mpeg2_scan_alt[i] = ((j & 0x36) >> 1) | ((j & 0x09) << 2);
}
}
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