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https://github.com/FFmpeg/FFmpeg.git
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ce467421dc
With explicit unrolling, we can skip half of the sign bit flips, and the compiler is then better able to optimise the scalar loop: predictor_c: 31376.0 (before) predictor_c: 23703.0 (after)
70 lines
1.8 KiB
C
70 lines
1.8 KiB
C
/*
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* This file is part of FFmpeg.
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*
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* Copyright (c) 2006 Industrial Light & Magic, a division of Lucas Digital Ltd. LLC
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdint.h>
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#include "libavutil/attributes.h"
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#include "exrdsp.h"
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#include "config.h"
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static void reorder_pixels_scalar(uint8_t *dst, const uint8_t *src, ptrdiff_t size)
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{
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const uint8_t *t1 = src;
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int half_size = size / 2;
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const uint8_t *t2 = src + half_size;
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uint8_t *s = dst;
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int i;
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for (i = 0; i < half_size; i++) {
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*(s++) = *(t1++);
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*(s++) = *(t2++);
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}
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}
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static void predictor_scalar(uint8_t *src, ptrdiff_t size)
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{
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/* Unrolled: `src[i + 1] += src[i] - 128;` */
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if ((size & 1) == 0) {
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src[1] += src[0] ^ 0x80;
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src++;
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size--;
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}
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for (ptrdiff_t i = 1; i < size; i += 2) {
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uint8_t a = src[i] + src[i - 1];
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src[i] = a;
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src[i + 1] += a;
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src[i] ^= 0x80;
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}
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}
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av_cold void ff_exrdsp_init(ExrDSPContext *c)
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{
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c->reorder_pixels = reorder_pixels_scalar;
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c->predictor = predictor_scalar;
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#if ARCH_RISCV
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ff_exrdsp_init_riscv(c);
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#elif ARCH_X86
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ff_exrdsp_init_x86(c);
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#endif
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}
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