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FFmpeg/libavutil/riscv/cpu.c
Rémi Denis-Courmont 37d5ddc317 lavu/riscv: CPU flag for the Zbb extension
Unfortunately, it is common, and will remain so, that the Bit
manipulations are not enabled at compilation time. This is an official
policy for Debian ports in general (though they do not support RISC-V
officially as of yet) to stick to the minimal target baseline, which
does not include the B extension or even its Zbb subset.

For inline helpers (CPOP, REV8), compiler builtins (CTZ, CLZ) or
even plain C code (MIN, MAX, MINU, MAXU), run-time detection seems
impractical. But at least it can work for the byte-swap DSP functions.
2022-10-05 08:26:19 +02:00

82 lines
2.2 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
*/
#include "libavutil/cpu.h"
#include "libavutil/cpu_internal.h"
#include "libavutil/log.h"
#include "config.h"
#if HAVE_GETAUXVAL
#include <sys/auxv.h>
#define HWCAP_RV(letter) (1ul << ((letter) - 'A'))
#endif
int ff_get_cpu_flags_riscv(void)
{
int ret = 0;
#if HAVE_GETAUXVAL
const unsigned long hwcap = getauxval(AT_HWCAP);
if (hwcap & HWCAP_RV('I'))
ret |= AV_CPU_FLAG_RVI;
if (hwcap & HWCAP_RV('F'))
ret |= AV_CPU_FLAG_RVF;
if (hwcap & HWCAP_RV('D'))
ret |= AV_CPU_FLAG_RVD;
if (hwcap & HWCAP_RV('B'))
ret |= AV_CPU_FLAG_RVB_BASIC;
/* The V extension implies all Zve* functional subsets */
if (hwcap & HWCAP_RV('V'))
ret |= AV_CPU_FLAG_RVV_I32 | AV_CPU_FLAG_RVV_I64
| AV_CPU_FLAG_RVV_F32 | AV_CPU_FLAG_RVV_F64;
#endif
#ifdef __riscv_i
ret |= AV_CPU_FLAG_RVI;
#endif
#if defined (__riscv_flen) && (__riscv_flen >= 32)
ret |= AV_CPU_FLAG_RVF;
#if (__riscv_flen >= 64)
ret |= AV_CPU_FLAG_RVD;
#endif
#endif
#ifdef __riscv_zbb
ret |= AV_CPU_FLAG_RVB_BASIC;
#endif
/* If RV-V is enabled statically at compile-time, check the details. */
#ifdef __riscv_vectors
ret |= AV_CPU_FLAG_RVV_I32;
#if __riscv_v_elen >= 64
ret |= AV_CPU_FLAG_RVV_I64;
#endif
#if __riscv_v_elen_fp >= 32
ret |= AV_CPU_FLAG_RVV_F32;
#if __riscv_v_elen_fp >= 64
ret |= AV_CPU_FLAG_RVV_F64;
#endif
#endif
#endif
return ret;
}