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ffmpeg/libavcodec/alpha/simple_idct_alpha.c

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/*
* Simple IDCT (Alpha optimized)
*
* Copyright (c) 2001 Michael Niedermayer <michaelni@gmx.at>
*
* based upon some outcommented C code from mpeg2dec (idct_mmx.c
* written by Aaron Holtzman <aholtzma@ess.engr.uvic.ca>)
*
* Alpha optimizations by Måns Rullgård <mans@mansr.com>
* and Falk Hueffner <falk@debian.org>
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavcodec/dsputil.h"
#include "dsputil_alpha.h"
#include "asm.h"
// cos(i * M_PI / 16) * sqrt(2) * (1 << 14)
// W4 is actually exactly 16384, but using 16383 works around
// accumulating rounding errors for some encoders
#define W1 22725
#define W2 21407
#define W3 19266
#define W4 16383
#define W5 12873
#define W6 8867
#define W7 4520
#define ROW_SHIFT 11
#define COL_SHIFT 20
/* 0: all entries 0, 1: only first entry nonzero, 2: otherwise */
static inline int idct_row(DCTELEM *row)
{
int a0, a1, a2, a3, b0, b1, b2, b3, t;
uint64_t l, r, t2;
l = ldq(row);
r = ldq(row + 4);
if (l == 0 && r == 0)
return 0;
a0 = W4 * sextw(l) + (1 << (ROW_SHIFT - 1));
if (((l & ~0xffffUL) | r) == 0) {
a0 >>= ROW_SHIFT;
t2 = (uint16_t) a0;
t2 |= t2 << 16;
t2 |= t2 << 32;
stq(t2, row);
stq(t2, row + 4);
return 1;
}
a1 = a0;
a2 = a0;
a3 = a0;
t = extwl(l, 4); /* row[2] */
if (t != 0) {
t = sextw(t);
a0 += W2 * t;
a1 += W6 * t;
a2 -= W6 * t;
a3 -= W2 * t;
}
t = extwl(r, 0); /* row[4] */
if (t != 0) {
t = sextw(t);
a0 += W4 * t;
a1 -= W4 * t;
a2 -= W4 * t;
a3 += W4 * t;
}
t = extwl(r, 4); /* row[6] */
if (t != 0) {
t = sextw(t);
a0 += W6 * t;
a1 -= W2 * t;
a2 += W2 * t;
a3 -= W6 * t;
}
t = extwl(l, 2); /* row[1] */
if (t != 0) {
t = sextw(t);
b0 = W1 * t;
b1 = W3 * t;
b2 = W5 * t;
b3 = W7 * t;
} else {
b0 = 0;
b1 = 0;
b2 = 0;
b3 = 0;
}
t = extwl(l, 6); /* row[3] */
if (t) {
t = sextw(t);
b0 += W3 * t;
b1 -= W7 * t;
b2 -= W1 * t;
b3 -= W5 * t;
}
t = extwl(r, 2); /* row[5] */
if (t) {
t = sextw(t);
b0 += W5 * t;
b1 -= W1 * t;
b2 += W7 * t;
b3 += W3 * t;
}
t = extwl(r, 6); /* row[7] */
if (t) {
t = sextw(t);
b0 += W7 * t;
b1 -= W5 * t;
b2 += W3 * t;
b3 -= W1 * t;
}
row[0] = (a0 + b0) >> ROW_SHIFT;
row[1] = (a1 + b1) >> ROW_SHIFT;
row[2] = (a2 + b2) >> ROW_SHIFT;
row[3] = (a3 + b3) >> ROW_SHIFT;
row[4] = (a3 - b3) >> ROW_SHIFT;
row[5] = (a2 - b2) >> ROW_SHIFT;
row[6] = (a1 - b1) >> ROW_SHIFT;
row[7] = (a0 - b0) >> ROW_SHIFT;
return 2;
}
static inline void idct_col(DCTELEM *col)
{
int a0, a1, a2, a3, b0, b1, b2, b3;
col[0] += (1 << (COL_SHIFT - 1)) / W4;
a0 = W4 * col[8 * 0];
a1 = W4 * col[8 * 0];
a2 = W4 * col[8 * 0];
a3 = W4 * col[8 * 0];
if (col[8 * 2]) {
a0 += W2 * col[8 * 2];
a1 += W6 * col[8 * 2];
a2 -= W6 * col[8 * 2];
a3 -= W2 * col[8 * 2];
}
if (col[8 * 4]) {
a0 += W4 * col[8 * 4];
a1 -= W4 * col[8 * 4];
a2 -= W4 * col[8 * 4];
a3 += W4 * col[8 * 4];
}
if (col[8 * 6]) {
a0 += W6 * col[8 * 6];
a1 -= W2 * col[8 * 6];
a2 += W2 * col[8 * 6];
a3 -= W6 * col[8 * 6];
}
if (col[8 * 1]) {
b0 = W1 * col[8 * 1];
b1 = W3 * col[8 * 1];
b2 = W5 * col[8 * 1];
b3 = W7 * col[8 * 1];
} else {
b0 = 0;
b1 = 0;
b2 = 0;
b3 = 0;
}
if (col[8 * 3]) {
b0 += W3 * col[8 * 3];
b1 -= W7 * col[8 * 3];
b2 -= W1 * col[8 * 3];
b3 -= W5 * col[8 * 3];
}
if (col[8 * 5]) {
b0 += W5 * col[8 * 5];
b1 -= W1 * col[8 * 5];
b2 += W7 * col[8 * 5];
b3 += W3 * col[8 * 5];
}
if (col[8 * 7]) {
b0 += W7 * col[8 * 7];
b1 -= W5 * col[8 * 7];
b2 += W3 * col[8 * 7];
b3 -= W1 * col[8 * 7];
}
col[8 * 0] = (a0 + b0) >> COL_SHIFT;
col[8 * 7] = (a0 - b0) >> COL_SHIFT;
col[8 * 1] = (a1 + b1) >> COL_SHIFT;
col[8 * 6] = (a1 - b1) >> COL_SHIFT;
col[8 * 2] = (a2 + b2) >> COL_SHIFT;
col[8 * 5] = (a2 - b2) >> COL_SHIFT;
col[8 * 3] = (a3 + b3) >> COL_SHIFT;
col[8 * 4] = (a3 - b3) >> COL_SHIFT;
}
/* If all rows but the first one are zero after row transformation,
all rows will be identical after column transformation. */
static inline void idct_col2(DCTELEM *col)
{
int i;
uint64_t l, r;
for (i = 0; i < 8; ++i) {
int a0 = col[i] + (1 << (COL_SHIFT - 1)) / W4;
a0 *= W4;
col[i] = a0 >> COL_SHIFT;
}
l = ldq(col + 0 * 4); r = ldq(col + 1 * 4);
stq(l, col + 2 * 4); stq(r, col + 3 * 4);
stq(l, col + 4 * 4); stq(r, col + 5 * 4);
stq(l, col + 6 * 4); stq(r, col + 7 * 4);
stq(l, col + 8 * 4); stq(r, col + 9 * 4);
stq(l, col + 10 * 4); stq(r, col + 11 * 4);
stq(l, col + 12 * 4); stq(r, col + 13 * 4);
stq(l, col + 14 * 4); stq(r, col + 15 * 4);
}
void ff_simple_idct_axp(DCTELEM *block)
{
int i;
int rowsZero = 1; /* all rows except row 0 zero */
int rowsConstant = 1; /* all rows consist of a constant value */
for (i = 0; i < 8; i++) {
int sparseness = idct_row(block + 8 * i);
if (i > 0 && sparseness > 0)
rowsZero = 0;
if (sparseness == 2)
rowsConstant = 0;
}
if (rowsZero) {
idct_col2(block);
} else if (rowsConstant) {
idct_col(block);
for (i = 0; i < 8; i += 2) {
uint64_t v = (uint16_t) block[0];
uint64_t w = (uint16_t) block[8];
v |= v << 16;
w |= w << 16;
v |= v << 32;
w |= w << 32;
stq(v, block + 0 * 4);
stq(v, block + 1 * 4);
stq(w, block + 2 * 4);
stq(w, block + 3 * 4);
block += 4 * 4;
}
} else {
for (i = 0; i < 8; i++)
idct_col(block + i);
}
}
void ff_simple_idct_put_axp(uint8_t *dest, int line_size, DCTELEM *block)
{
ff_simple_idct_axp(block);
put_pixels_clamped_axp_p(block, dest, line_size);
}
void ff_simple_idct_add_axp(uint8_t *dest, int line_size, DCTELEM *block)
{
ff_simple_idct_axp(block);
add_pixels_clamped_axp_p(block, dest, line_size);
}
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