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https://git.ffmpeg.org/ffmpeg.git
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1e519b9d40
this allows disabling and enabling it it also prevents crashes if vfpv3 and neon are disabled which previously would have enabled the flag And last but not least one can enable setend on cpus like cortex-a8 where its fast but disabled by default Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
157 lines
4.5 KiB
C
157 lines
4.5 KiB
C
/*
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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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#include "libavutil/cpu.h"
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#include "libavutil/cpu_internal.h"
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#include "config.h"
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#define CORE_FLAG(f) \
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(AV_CPU_FLAG_ ## f * (HAVE_ ## f ## _EXTERNAL || HAVE_ ## f ## _INLINE))
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#define CORE_CPU_FLAGS \
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(CORE_FLAG(ARMV5TE) | \
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CORE_FLAG(ARMV6) | \
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CORE_FLAG(ARMV6T2) | \
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CORE_FLAG(VFP) | \
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CORE_FLAG(VFPV3) | \
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CORE_FLAG(NEON))
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#if defined __linux__ || defined __ANDROID__
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include "libavutil/avstring.h"
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#define AT_HWCAP 16
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/* Relevant HWCAP values from kernel headers */
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#define HWCAP_VFP (1 << 6)
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#define HWCAP_EDSP (1 << 7)
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#define HWCAP_THUMBEE (1 << 11)
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#define HWCAP_NEON (1 << 12)
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#define HWCAP_VFPv3 (1 << 13)
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#define HWCAP_TLS (1 << 15)
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static int get_hwcap(uint32_t *hwcap)
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{
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struct { uint32_t a_type; uint32_t a_val; } auxv;
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FILE *f = fopen("/proc/self/auxv", "r");
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int err = -1;
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if (!f)
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return -1;
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while (fread(&auxv, sizeof(auxv), 1, f) > 0) {
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if (auxv.a_type == AT_HWCAP) {
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*hwcap = auxv.a_val;
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err = 0;
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break;
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}
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}
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fclose(f);
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return err;
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}
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static int get_cpuinfo(uint32_t *hwcap)
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{
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FILE *f = fopen("/proc/cpuinfo", "r");
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char buf[200];
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if (!f)
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return -1;
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*hwcap = 0;
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while (fgets(buf, sizeof(buf), f)) {
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if (av_strstart(buf, "Features", NULL)) {
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if (strstr(buf, " edsp "))
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*hwcap |= HWCAP_EDSP;
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if (strstr(buf, " tls "))
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*hwcap |= HWCAP_TLS;
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if (strstr(buf, " thumbee "))
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*hwcap |= HWCAP_THUMBEE;
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if (strstr(buf, " vfp "))
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*hwcap |= HWCAP_VFP;
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if (strstr(buf, " vfpv3 "))
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*hwcap |= HWCAP_VFPv3;
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if (strstr(buf, " neon ") || strstr(buf, " asimd "))
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*hwcap |= HWCAP_NEON;
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if (strstr(buf, " fp ")) // Listed on 64 bit ARMv8 kernels
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*hwcap |= HWCAP_VFP | HWCAP_VFPv3;
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break;
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}
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}
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fclose(f);
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return 0;
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}
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int ff_get_cpu_flags_arm(void)
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{
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int flags = CORE_CPU_FLAGS;
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uint32_t hwcap;
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if (get_hwcap(&hwcap) < 0)
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if (get_cpuinfo(&hwcap) < 0)
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return flags;
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#define check_cap(cap, flag) do { \
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if (hwcap & HWCAP_ ## cap) \
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flags |= AV_CPU_FLAG_ ## flag; \
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} while (0)
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/* No flags explicitly indicate v6 or v6T2 so check others which
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imply support. */
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check_cap(EDSP, ARMV5TE);
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check_cap(TLS, ARMV6);
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check_cap(THUMBEE, ARMV6T2);
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check_cap(VFP, VFP);
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check_cap(VFPv3, VFPV3);
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check_cap(NEON, NEON);
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/* The v6 checks above are not reliable so let higher flags
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trickle down. */
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if (flags & (AV_CPU_FLAG_VFPV3 | AV_CPU_FLAG_NEON))
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flags |= AV_CPU_FLAG_ARMV6T2;
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else
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/* Some functions use the 'setend' instruction which is deprecated on ARMv8
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* and serializing on some ARMv7 cores. This ensures such functions
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* are only enabled on ARMv6. */
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flags |= AV_CPU_FLAG_SETEND;
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if (flags & AV_CPU_FLAG_ARMV6T2)
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flags |= AV_CPU_FLAG_ARMV6;
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return flags;
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}
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#else
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int ff_get_cpu_flags_arm(void)
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{
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return AV_CPU_FLAG_ARMV5TE * HAVE_ARMV5TE |
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AV_CPU_FLAG_ARMV6 * HAVE_ARMV6 |
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AV_CPU_FLAG_ARMV6T2 * HAVE_ARMV6T2 |
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AV_CPU_FLAG_VFP * HAVE_VFP |
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AV_CPU_FLAG_VFPV3 * HAVE_VFPV3 |
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AV_CPU_FLAG_NEON * HAVE_NEON |
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AV_CPU_FLAG_SETEND * !(HAVE_NEON | HAVE_VFPV3);
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}
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#endif
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