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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>
*
* This library 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 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* based upon some outcommented c code from mpeg2dec (idct_mmx.c
* written by Aaron Holtzman <aholtzma@ess.engr.uvic.ca>)
*
* Alpha optimiziations by Måns Rullgård <mru@users.sourceforge.net>
* and Falk Hueffner <falk@debian.org>
*/
#include "asm.h"
#include "../dsputil.h"
extern void (*put_pixels_clamped_axp_p)(const DCTELEM *block, uint8_t *pixels,
int line_size);
extern void (*add_pixels_clamped_axp_p)(const DCTELEM *block, uint8_t *pixels,
int line_size);
// 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 ((int_fast32_t) 22725)
#define W2 ((int_fast32_t) 21407)
#define W3 ((int_fast32_t) 19266)
#define W4 ((int_fast32_t) 16383)
#define W5 ((int_fast32_t) 12873)
#define W6 ((int_fast32_t) 8867)
#define W7 ((int_fast32_t) 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_fast32_t a0, a1, a2, a3, b0, b1, b2, b3, t;
uint64_t l, r;
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;
a0 = (uint16_t) a0;
a0 |= a0 << 16;
a0 |= a0 << 32;
stq(a0, row);
stq(a0, 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_fast32_t 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;
uint64_t *lcol = (uint64_t *) col;
for (i = 0; i < 8; ++i) {
int_fast32_t a0 = col[0] + (1 << (COL_SHIFT - 1)) / W4;
a0 *= W4;
col[0] = a0 >> COL_SHIFT;
++col;
}
l = lcol[0];
r = lcol[1];
lcol[ 2] = l; lcol[ 3] = r;
lcol[ 4] = l; lcol[ 5] = r;
lcol[ 6] = l; lcol[ 7] = r;
lcol[ 8] = l; lcol[ 9] = r;
lcol[10] = l; lcol[11] = r;
lcol[12] = l; lcol[13] = r;
lcol[14] = l; lcol[15] = r;
}
void 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) {
uint64_t *lblock = (uint64_t *) block;
idct_col(block);
for (i = 0; i < 8; i += 2) {
uint64_t v = (uint16_t) block[i * 8];
uint64_t w = (uint16_t) block[i * 8 + 8];
v |= v << 16;
w |= w << 16;
v |= v << 32;
w |= w << 32;
lblock[0] = v;
lblock[1] = v;
lblock[2] = w;
lblock[3] = w;
lblock += 4;
}
} else {
for (i = 0; i < 8; i++)
idct_col(block + i);
}
}
void simple_idct_put_axp(uint8_t *dest, int line_size, DCTELEM *block)
{
simple_idct_axp(block);
put_pixels_clamped_axp_p(block, dest, line_size);
}
void simple_idct_add_axp(uint8_t *dest, int line_size, DCTELEM *block)
{
simple_idct_axp(block);
add_pixels_clamped_axp_p(block, dest, line_size);
}
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