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diff --git a/libmpeg2/idct.c b/libmpeg2/idct.c
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+/*
+ * idct.c
+ * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
+ *
+ * Portions of this code are from the MPEG software simulation group
+ * idct implementation. This code will be replaced with a new
+ * implementation soon.
+ *
+ * This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
+ *
+ * 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
+ */
+
+/**********************************************************/
+/* inverse two dimensional DCT, Chen-Wang algorithm */
+/* (cf. IEEE ASSP-32, pp. 803-816, Aug. 1984) */
+/* 32-bit integer arithmetic (8 bit coefficients) */
+/* 11 mults, 29 adds per DCT */
+/* sE, 18.8.91 */
+/**********************************************************/
+/* coefficients extended to 12 bit for IEEE1180-1990 */
+/* compliance sE, 2.1.94 */
+/**********************************************************/
+
+/* this code assumes >> to be a two's-complement arithmetic */
+/* right shift: (-2)>>1 == -1 , (-3)>>1 == -2 */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <inttypes.h>
+
+#include "mpeg2_internal.h"
+#include "mm_accel.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 (*idct_block_copy) (int16_t * block, uint8_t * dest, int stride);
+void (*idct_block_add) (int16_t * block, uint8_t * dest, int stride);
+
+static void idct_block_copy_c (int16_t *block, uint8_t * dest, int stride);
+static void idct_block_add_c (int16_t *block, uint8_t * dest, int stride);
+
+static uint8_t clip_lut[1024];
+#define CLIP(i) ((clip_lut+384)[ (i)])
+
+void idct_init (void)
+{
+#ifdef ARCH_X86
+ if (config.flags & MM_ACCEL_X86_MMXEXT) {
+ fprintf (stderr, "Using MMXEXT for IDCT transform\n");
+ idct_block_copy = idct_block_copy_mmxext;
+ idct_block_add = idct_block_add_mmxext;
+ idct_mmx_init ();
+ } else if (config.flags & MM_ACCEL_X86_MMX) {
+ fprintf (stderr, "Using MMX for IDCT transform\n");
+ idct_block_copy = idct_block_copy_mmx;
+ idct_block_add = idct_block_add_mmx;
+ idct_mmx_init ();
+ } else
+#endif
+#ifdef LIBMPEG2_MLIB
+ if (config.flags & MM_ACCEL_MLIB) {
+ fprintf (stderr, "Using mlib for IDCT transform\n");
+ idct_block_copy = idct_block_copy_mlib;
+ idct_block_add = idct_block_add_mlib;
+ } else
+#endif
+ {
+ int i;
+
+ fprintf (stderr, "No accelerated IDCT transform found\n");
+ idct_block_copy = idct_block_copy_c;
+ idct_block_add = idct_block_add_c;
+ for (i = -384; i < 640; i++)
+ clip_lut[i+384] = (i < 0) ? 0 : ((i > 255) ? 255 : i);
+ }
+}
+
+/* row (horizontal) IDCT
+ *
+ * 7 pi 1
+ * dst[k] = sum c[l] * src[l] * cos ( -- * ( k + - ) * l )
+ * l=0 8 2
+ *
+ * where: c[0] = 128
+ * c[1..7] = 128*sqrt (2)
+ */
+
+static void inline idct_row (int16_t * block)
+{
+ int x0, x1, x2, x3, x4, x5, x6, x7, x8;
+
+ x1 = block[4] << 11;
+ x2 = block[6];
+ x3 = block[2];
+ x4 = block[1];
+ x5 = block[7];
+ x6 = block[5];
+ x7 = block[3];
+
+ /* shortcut */
+ if (! (x1 | x2 | x3 | x4 | x5 | x6 | x7 )) {
+ block[0] = block[1] = block[2] = block[3] = block[4] =
+ block[5] = block[6] = block[7] = block[0]<<3;
+ return;
+ }
+
+ x0 = (block[0] << 11) + 128; /* for proper rounding in the fourth stage */
+
+ /* first stage */
+ x8 = W7 * (x4 + x5);
+ x4 = x8 + (W1 - W7) * x4;
+ x5 = x8 - (W1 + W7) * x5;
+ x8 = W3 * (x6 + x7);
+ x6 = x8 - (W3 - W5) * x6;
+ x7 = x8 - (W3 + W5) * x7;
+
+ /* second stage */
+ x8 = x0 + x1;
+ x0 -= x1;
+ x1 = W6 * (x3 + x2);
+ x2 = x1 - (W2 + W6) * x2;
+ x3 = x1 + (W2 - W6) * x3;
+ x1 = x4 + x6;
+ x4 -= x6;
+ x6 = x5 + x7;
+ x5 -= x7;
+
+ /* third stage */
+ x7 = x8 + x3;
+ x8 -= x3;
+ x3 = x0 + x2;
+ x0 -= x2;
+ x2 = (181 * (x4 + x5) + 128) >> 8;
+ x4 = (181 * (x4 - x5) + 128) >> 8;
+
+ /* fourth stage */
+ block[0] = (x7 + x1) >> 8;
+ block[1] = (x3 + x2) >> 8;
+ block[2] = (x0 + x4) >> 8;
+ block[3] = (x8 + x6) >> 8;
+ block[4] = (x8 - x6) >> 8;
+ block[5] = (x0 - x4) >> 8;
+ block[6] = (x3 - x2) >> 8;
+ block[7] = (x7 - x1) >> 8;
+}
+
+/* column (vertical) IDCT
+ *
+ * 7 pi 1
+ * dst[8*k] = sum c[l] * src[8*l] * cos ( -- * ( k + - ) * l )
+ * l=0 8 2
+ *
+ * where: c[0] = 1/1024
+ * c[1..7] = (1/1024)*sqrt (2)
+ */
+
+static void inline idct_col (int16_t *block)
+{
+ int x0, x1, x2, x3, x4, x5, x6, x7, x8;
+
+ /* shortcut */
+ x1 = block [8*4] << 8;
+ x2 = block [8*6];
+ x3 = block [8*2];
+ x4 = block [8*1];
+ x5 = block [8*7];
+ x6 = block [8*5];
+ x7 = block [8*3];
+
+#if 0
+ if (! (x1 | x2 | x3 | x4 | x5 | x6 | x7 )) {
+ block[8*0] = block[8*1] = block[8*2] = block[8*3] = block[8*4] =
+ block[8*5] = block[8*6] = block[8*7] = (block[8*0] + 32) >> 6;
+ return;
+ }
+#endif
+
+ x0 = (block[8*0] << 8) + 8192;
+
+ /* first stage */
+ x8 = W7 * (x4 + x5) + 4;
+ x4 = (x8 + (W1 - W7) * x4) >> 3;
+ x5 = (x8 - (W1 + W7) * x5) >> 3;
+ x8 = W3 * (x6 + x7) + 4;
+ x6 = (x8 - (W3 - W5) * x6) >> 3;
+ x7 = (x8 - (W3 + W5) * x7) >> 3;
+
+ /* second stage */
+ x8 = x0 + x1;
+ x0 -= x1;
+ x1 = W6 * (x3 + x2) + 4;
+ x2 = (x1 - (W2 + W6) * x2) >> 3;
+ x3 = (x1 + (W2 - W6) * x3) >> 3;
+ x1 = x4 + x6;
+ x4 -= x6;
+ x6 = x5 + x7;
+ x5 -= x7;
+
+ /* third stage */
+ x7 = x8 + x3;
+ x8 -= x3;
+ x3 = x0 + x2;
+ x0 -= x2;
+ x2 = (181 * (x4 + x5) + 128) >> 8;
+ x4 = (181 * (x4 - x5) + 128) >> 8;
+
+ /* fourth stage */
+ block[8*0] = (x7 + x1) >> 14;
+ block[8*1] = (x3 + x2) >> 14;
+ block[8*2] = (x0 + x4) >> 14;
+ block[8*3] = (x8 + x6) >> 14;
+ block[8*4] = (x8 - x6) >> 14;
+ block[8*5] = (x0 - x4) >> 14;
+ block[8*6] = (x3 - x2) >> 14;
+ block[8*7] = (x7 - x1) >> 14;
+}
+
+void idct_block_copy_c (int16_t * block, uint8_t * dest, 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);
+
+ i = 8;
+ 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]);
+
+ dest += stride;
+ block += 8;
+ } while (--i);
+}
+
+void idct_block_add_c (int16_t * block, uint8_t * dest, 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);
+
+ i = 8;
+ 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]);
+
+ dest += stride;
+ block += 8;
+ } while (--i);
+}
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