ffmpeg/libavutil/riscv/cpu.h

67 lines
1.9 KiB
C

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