ops_impl.h

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/*
 * Copyright (C) 2026 Ramiro Polla
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
 
#ifndef SWSCALE_AARCH64_OPS_IMPL_H
#define SWSCALE_AARCH64_OPS_IMPL_H
 
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
 
#include "libswscale/uops.h"
 
/* Each nibble in the mask corresponds to one component. */
#define NIBBLE_GET(mask, idx) (((mask) >> ((idx) << 2)) & 0xf)
#define NIBBLE_SET(mask, idx, val) do { (mask) |= (((val) & 0xf) << ((idx) << 2)); } while (0)
 
static inline uint16_t nibble_mask(SwsCompMask mask)
{
    uint16_t ret = 0;
    for (int i = 0; i < 4; i++)
        NIBBLE_SET(ret, i, !!(mask & SWS_COMP(i)));
    return ret;
}
 
/**
 * SwsAArch64OpImplParams describes the parameters for an SwsUOpType
 * operation. It consists of simplified parameters from the SwsUOp structure,
 * with the purpose of being straight-forward to implement and execute.
 */
typedef struct SwsAArch64OpImplParams {
    SwsUOpType          uop;
    SwsCompMask         mask;
    SwsPixelType        type;
    uint8_t block_size;
    SwsUOpParams par;
} SwsAArch64OpImplParams;
 
/* SwsCompMask-related helpers. */
#define LOOP(mask, idx)                 \
    for (int idx = 0; idx < 4; idx++)   \
        if (mask & SWS_COMP(idx))
#define LOOP_BWD(mask, idx)             \
    for (int idx = 3; idx >= 0; idx--)  \
        if (mask & SWS_COMP(idx))
 
#define LOOP_MASK(p, idx) LOOP(p->mask, idx)
#define LOOP_MASK_BWD(p, idx) LOOP_BWD(p->mask, idx)
 
/* Number of elements in each linear coefficient vector register. */
static inline int linear_vreg_nelems(SwsPixelType type)
{
    return 16 / ff_sws_pixel_type_size(type);
}
 
/* Compute number of vector registers needed to store all coefficients. */
static inline int linear_num_vregs(const SwsAArch64OpImplParams *params)
{
    int count = 0;
    for (int i = 0; i < 4 * 5; i++)
        if (!(params->par.lin.zero & (1ULL << i)))
            count++;
    const int nelems = linear_vreg_nelems(params->type);
    return (count + nelems - 1) / nelems;
}
 
/**
 * These values will be used by ops_asmgen to access fields inside of
 * SwsOpExec and SwsOpImpl. The sizes are checked in aarch64/ops.c when
 * compiling for AArch64 to make sure there is no mismatch.
 */
#define offsetof_exec_in         0
#define offsetof_exec_out       32
#define offsetof_exec_in_bump  128
#define offsetof_exec_out_bump 160
#define offsetof_impl_cont       0
#define offsetof_impl_priv      16
#define sizeof_impl             32
 
#endif /* SWSCALE_AARCH64_OPS_IMPL_H */