mirror of https://git.ffmpeg.org/ffmpeg.git
67 lines
1.9 KiB
C
67 lines
1.9 KiB
C
/*
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* Copyright © 2022 Rémi Denis-Courmont.
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*
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* This file is part of FFmpeg.
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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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#ifndef AVUTIL_RISCV_CPU_H
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#define AVUTIL_RISCV_CPU_H
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#include "config.h"
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#include <stdbool.h>
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#include <stddef.h>
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#include "libavutil/cpu.h"
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#if HAVE_RVV
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/**
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* Returns the vector size in bytes (always a power of two and at least 4).
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* This is undefined behaviour if vectors are not implemented.
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*/
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static inline size_t ff_get_rv_vlenb(void)
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{
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size_t vlenb;
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__asm__ (
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".option push\n"
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".option arch, +v\n"
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" csrr %0, vlenb\n"
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".option pop\n" : "=r" (vlenb));
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return vlenb;
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}
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#endif
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/**
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* Checks that the vector bit-size is at least the given value.
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* This is potentially undefined behaviour if vectors are not implemented.
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*/
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static inline bool ff_rv_vlen_least(unsigned int bits)
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{
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#ifdef __riscv_v_min_vlen
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if (bits <= __riscv_min_vlen)
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return true;
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#else
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/*
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* Vector lengths smaller than 128 bits are only possible in embedded cases
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* and cannot be run-time detected, so we can assume 128 bits at least.
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*/
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if (bits <= 128)
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return true;
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#endif
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return bits <= (8 * ff_get_rv_vlenb());
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}
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#endif
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